{"url_path":"/sec/ati/proxy/2026-03-24/000119312526121340","section_key":"body","section_title":"DEF 14A body","topic":"sec","document":{"doc_type":"DEF 14A","doc_date":"2026-03-24","source_url":"https://www.sec.gov/Archives/edgar/data/1018963/0001193125-26-121340-index.html","accession_number":"0001193125-26-121340","cik":"0001018963","ticker":"ATI","issuer_name":"ATI INC","edgar_url":"https://www.sec.gov/Archives/edgar/data/1018963/0001193125-26-121340-index.html","primary_entity_key":"0001018963","primary_entity_name":"ATI INC"},"word_count":41523,"has_tables":true,"body_markdown":"DEF 14A\n\n##### Table of Contents\n\nDEF 14Afalse0001018963 0001018963 2024-12-30 2025-12-28 0001018963 2022-01-03 2023-01-01 0001018963 2023-01-02 2023-12-31 0001018963 2021-01-04 2022-01-02 0001018963 2024-01-01 2024-12-29 0001018963 ati:RobertSWetherbeeMember 2021-01-04 2022-01-02 0001018963 ecd:FrValAsOfPrrYrEndOfEqtyAwrdsGrntdInPrrYrsFldVstngCondsDrngCvrdYrMember ecd:NonPeoNeoMember 2021-01-04 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ati:KimberlyAFieldsMember 2024-12-30 2025-12-28 0001018963 ati:PensionValueMember ecd:PeoMember ati:KimberlyAFieldsMember 2024-12-30 2025-12-28 0001018963 1 2024-12-30 2025-12-28 0001018963 2 2024-12-30 2025-12-28 0001018963 3 2024-12-30 2025-12-28 0001018963 4 2024-12-30 2025-12-28 0001018963 5 2024-12-30 2025-12-28 0001018963 6 2024-12-30 2025-12-28 0001018963 ati:RobertSWetherbeeMember 2024-12-30 2025-12-28 iso4217:USD\n\n \n\n \n\nUNITED STATES\n\nSECURITIES AND EXCHANGE COMMISSION\n\nWashington, D.C. 20549\n\nSCHEDULE 14A\n\n(Rule\n14a-101)\n\nINFORMATION REQUIRED IN PROXY STATEMENT\n\nSCHEDULE 14A INFORMATION\n\nProxy Statement Pursuant To Section 14(a) of the\n\nSecurities Exchange Act of 1934\n\nFiled by the Registrant ☒        Filed by a Party other than the Registrant ☐\n\nCheck the appropriate box:\n\n \n\n☐\n\n  \nPreliminary Proxy Statement\n\n☐\n\n  \n\nConfidential, for Use of the Commission Only (as permitted by Rule\n14a-6(e)(2))\n\n☒\n\n  \nDefinitive Proxy Statement\n\n☐\n\n  \nDefinitive Additional Materials\n\n☐\n\n  \nSoliciting Material Pursuant to\n§240.14a-12\n\n  \n\nATI Inc.\n\n  \n\n(Name of Registrant as Specified In Its Charter)\n\n  \n\n  \n\n  \n\n(Name of Person(s) Filing Proxy Statement, if other than the Registrant)\n\nPayment of Filing Fee (Check all boxes that apply):\n\n☒\n\n  \nNo fee required.\n\n☐\n\n  \nFee paid previously with preliminary materials.\n\n☐\n\n  \n\nFee computed on table in exhibit required by Item 25(b) per Exchange Act Rules 14a-6(i)(1) and 0-11.\n\n \n\n \n\n \n\n##### Table of Contents\n\nAND NOTICE OF ANNUAL MEETING OF STOCKHOLDERS\nanywhere.\nProven to perform\n2026 proxy statement\n\n##### Table of Contents\n\nWho we are.\nATI is a global producer of high performance materials and solutions for\nthe aerospace and defense markets, with emerging opportunities for\nspecialty energy.\nBuilt on the strong foundation of our legacy companies, we are a global\nmarket-driven powerhouse: advanced, innovative, highly sophisticated\nand quality driven.\nWhen you need materials to go further and faster, in the most\nextreme conditions, ATI is Proven to Perform.\nCore Markets\nDEFENSE\nOur materials power and protect the\narmed services in the air, sea and on\nthe ground, and help to push the\nlimits of space.\nAEROSPACE\nYou can’t fly without ATI — our\nmaterials are on virtually every\ncommercial aircraft flying\ntoday — engines and air frames.\nSPECIALTY ENERGY\nOur alloys fuel electrical energy in\nnuclear reactors, renewables, and\nland-based turbines. Our oil and gas\nmaterials fight heat and corrosion\ndeep in the sea.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n1 \n\n \n\n \n\n  \n\n \n\nATI Inc.\n\n2021 McKinney Avenue\n\nDallas, TX 75201\n\n \n\nDear Stockholders\n\n \n\nI am pleased to invite you to attend ATI’s 2026 Annual Meeting of Stockholders.\n\nAs I approach two years as ATI’s President and CEO, I am confident in ATI’s direction and the progress we are making. Over the past several years, we have sharpened our strategic focus, strengthened our financial profile and positioned ATI to deliver sustained long-term value. \n\nIn 2025, ATI delivered $4.6 billion in revenue—our highest level in 14 years. We have transformed tremendously over that time. Today, we are a fundamentally different and significantly more profitable business. Most importantly, through disciplined execution, we have exceeded profit and cash flow expectations, improved operational reliability, and strengthened customer relationships, gaining share in our highest value markets. These results reflect a clear strategy and a team committed to execution and accountability.\n\nOur evolution into a focused aerospace and defense leader continues to gain momentum. Aerospace and defense represented 68% of full-year sales in 2025, surpassing our prior 65% target. We participate in every major commercial airframe and engine program and continue to expand our presence across critical defense platforms. Demand for mission-critical materials remains robust, and our differentiated capabilities position ATI as a strategic supplier across long-cycle programs and next-generation technologies.\n\nTo meet demand responsibly, we are maintaining a return-focused approach to capital allocation. Beginning in 2024, we expanded titanium melt capacity, supported by customer commitments. We are now advancing disciplined growth plans in highly differentiated nickel melt capacity. Each investment is evaluated through a rigorous return framework designed to enhance competitive advantage while preserving balance sheet strength and financial flexibility.\n\nBeyond aerospace and defense, we are selectively pursuing opportunities in other high-value markets where ATI’s capabilities create clear differentiation. Nuclear and specialty energy markets represent promising areas for growth. While a smaller portion of our portfolio today, this business is scaling quickly as demand for AI-driven infrastructure accelerates. Our capabilities in zirconium, hafnium and other specialty alloys position ATI as a trusted and technically advantaged supplier in these applications.\n\nAcross all of our growing markets, one thing is clear: our customers value the execution, quality and reliability we deliver. Our commitment is to deliver mission-critical materials safely, consistently and efficiently, while continuously improving how we operate. \n\nWe are equally committed to disciplined shareholder stewardship. In 2025, while continuing to invest in high-return growth initiatives, we repurchased $470 million of our outstanding shares. Our capital allocation strategy balances reinvestment for growth with prudent returns to stockholders and continued financial strength. \n\nATI’s stock performance over the past several years reflects sustained operational progress across multiple performance cycles. As illustrated in this Proxy Statement, we are outpacing markets and peers in driving standout returns over time. A $100 investment in ATI at the outset of 2022 is worth over $900 as of the record date for the Annual Meeting and has grown by more than 160% just since the beginning of 2025.\n\nOur team, guided by our culture and core values, is committed to continued success. With each goal met, they strive to set the bar higher. We do what we say we’re going to do, when we say we’re going to do it, in the right way. These values permeate our culture, driving shareholder value creation, a commitment to investor outreach, robust corporate governance and my commitment to developing and supporting our team.\n\nAt the conclusion of the Annual Meeting, I will assume the role of Board Chair. I appreciate Bob Wetherbee’s service during his tenure and his role in supporting ATI’s strategic repositioning. We will continue building on that progress with disciplined execution and a clear focus on long-term value creation. On behalf of the ATI team, thank you for your trust and support of ATI.\n\n \n\n  \n\n \n\nSincerely,\n\n \n\n \n\nKimberly A. Fields\n\nPresident and CEO; Chair-Elect\n\nMarch 24, 2026\n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n2\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nNotice of Annual Meeting\n\nof Stockholders\n\n \n \n\n \n\nAnnual Meeting Information\n\n \n\n \n\n \n\n \n\nDATE & TIME:\n\nThursday, May 14, 2026\n\n11:30 a.m. Central Time\n\n \n\n \n\n \n\nVIRTUAL MEETING SITE:\n\nwww.meetnow.global/MSSZRJ5\n\n \n\n \n\nRECORD DATE:\n\nMarch 16, 2026\n\n \n\n \n\nAgenda\n\n \n\n1.\n\nElect three directors;\n\n \n\n2.\n\nApprove, by advisory vote, the\n\n \n\ncompensation of our named\n\n \n\nexecutive officers; and\n\n \n\n3.\n\nRatify the selection of Ernst &\n\n \n\nYoung LLP as our independent\n\n \n\nauditors for 2026.\n\n \n\nYour vote is important\n\nPlease vote as soon as possible.\n\n \n\nYou can help us reduce expenses and obtain a quorum to conduct business at the Annual Meeting by voting your shares in advance by telephone or internet.\n\n \n\nHow to vote\n\n \n\n \n\n  \n\nVia the internet Visit the\nwebsite listed on our\nproxy card\n\n \n\n \n\n \n\n  \n\n \n\nBy mail Sign, date and return\nyour proxy card in the\nenclosed envelope\n\n \n\n \n\n \n\n  \n\n \n\nBy telephone Call the\ntelephone number on your\nproxy card\n\n \n\n \n\n \n\n  \n\n \n\nDuring the Virtual Meeting Attend the Annual Meeting\nwhich is being presented\nvirtually via webcast and vote\nonline during the meeting\n\nAdmission to the Meeting\n\nYou are entitled to participate, vote and submit questions at ATI Inc.’s virtual 2026 Annual Meeting if you were a stockholder of record as of the close of business on March 16, 2026 or you hold a legal proxy for the meeting provided by your bank, broker or nominee.\n\nStockholders of Record. You will be able to participate, vote electronically and submit questions during the live webcast of the 2026 Annual Meeting without advance registration. To access the live webcast of the meeting, you will need the 15-digit control number on the proxy card or the “Notice Regarding the Availability of Proxy Materials” (the “Notice”) you previously received.\n\nBeneficial Owners. If you are a beneficial owner and hold your shares through an intermediary, such as a bank, broker, or nominee, you must register in advance to participate in, vote electronically at, or submit questions during the live webcast of the 2026 Annual Meeting. To register in advance, you must obtain a legal proxy from the bank, broker or other nominee that holds your shares giving you the right to vote the shares. Please forward a copy of the legal proxy, along with your email address, to Computershare Trust Company, N.A. (“Computershare”) by email at legalproxy@computershare.com no later than 4:00 p.m. Central Time, on Monday, May 11, 2026. You will receive confirmation of your registration and instructions on how to attend the meeting by email after Computershare receives your registration materials.\n\nBeneficial owners that are unable to register in advance may still attend the 2026 Annual Meeting by visiting www.meetnow.global/MSSZRJ5 as a “guest” but will not have the option to vote shares electronically or submit questions during the live webcast of the meeting. However, you may submit questions in advance of the meeting by emailing your question, along with proof of ownership, to investors@ATlmaterials.com.\n\nOur Proxy Statement and 2025 Annual Report are available for review by stockholders of record at envisionreports.com/ATI and by beneficial owners at edocumentreview.com/ATI. For further information about ATI, please visit our website at atimaterials.com. This Proxy Statement is first being provided to our stockholders on or about March 24, 2026.\n\nOn behalf of the Board of Directors:\n\n \n\nAmanda J. Skov\n\nCorporate Secretary\n\nMarch 24, 2026\n\nImportant notice regarding the availability of proxy materials for the ATI Annual Meeting of Stockholders to be held on Thursday, May 14, 2026.\n\nAs permitted under applicable Securities and Exchange Commission (“SEC”) rules, we are mailing our stockholders a Notice of Internet Availability of Proxy Materials containing instructions on how to access our proxy materials and submit proxy votes online. Our Proxy Statement, proxy card and 2025 Annual Report are available for review at: envisionreports.com/ATI.\n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n3 \n\n \n\nTable of Contents\n\n \n\n[Proxy Statement Summary](#txa932857_1)\n  \n \n4\n \n\n[Proposal 1: Election of Directors](#txa932857_2)\n  \n \n11\n \n\n[Director Terms](#txa932857_3)\n  \n \n11\n \n\n[Our Director Nomination Process](#txa932857_4)\n  \n \n11\n \n\n[Our 2026 Director Nominees and Continuing Directors](#txa932857_5)\n  \n \n13\n \n\n[Our Corporate Governance](#txa932857_6)\n  \n \n20\n \n\n[Our Commitment to Integrity, Corporate Governance and Sustainability](#txa932857_7)\n  \n \n20\n \n\n[ATI Corporate Governance at a Glance](#txa932857_8)\n  \n \n21\n \n\n[Our Board and Its Role](#txa932857_9)\n  \n \n22\n \n\n[Our Board Leadership Structure](#txa932857_10)\n\n  \n \n22\n \n\n[The Role of Our Board](#txa932857_11)\n\n  \n \n23\n \n\n[Board Committees](#txa932857_12)\n\n  \n \n27\n \n\n[Governance Policies and Practices](#txa932857_13)\n  \n \n30\n \n\n[Corporate Governance Guidelines](#txa932857_14)\n\n  \n \n30\n \n\n[Board Independence](#txa932857_15)\n\n  \n \n30\n \n\n[Board Self-Assessment](#txa932857_16)\n\n  \n \n30\n \n\n[Director Attendance at Meetings](#txa932857_17)\n\n  \n \n30\n \n\n[Code of Conduct](#txa932857_18)\n\n  \n \n31\n \n\n[Employee Training](#txa932857_19)\n\n  \n \n31\n \n\n[Related Party Transactions](#txa932857_20)\n\n  \n \n31\n \n\n[Compensation Committee Interlocks and Insider Participation](#txa932857_21)\n\n  \n \n31\n \n\n[Section 16 Filings](#txa932857_22)\n\n  \n \n31\n \n\n[Investor Outreach and Stockholder Engagement](#txa932857_23)\n  \n \n32\n \n\n[Director Compensation](#txa932857_25)\n  \n \n33\n \n\n[Our Approach to Corporate Responsibility](#txa932857_26)\n  \n \n34\n \n\n[Our Core Values](#txa932857_27)\n\n  \n \n34\n \n\n[Environmental Stewardship](#txa932857_28)\n\n  \n \n35\n \n\n[Talent and Culture](#txa932857_29)\n\n  \n \n36\n \n\n[Corporate Responsibility Reporting](#txa932857_30)\n\n  \n \n36\n \n\n[ATI’s Executive Management](#txa932857_31)\n  \n \n37\n \n\n[Proposal 2: Advisory Vote to Approve the Compensation of the Company’s Named Executive Officers](#txa932857_32)\n  \n \n38\n \n\n[Executive Compensation](#txa932857_33)\n  \n \n40\n \n\n[Compensation Discussion and Analysis (See separate Table of Contents)](#txa932857_34)\n\n  \n \n40\n \n\n[2025 Compensation Tables](#txa932857_34a)\n\n  \n \n61\n \n\n[CEO Pay Ratio](#txa932857_35)\n\n  \n \n73\n \n\n[Pay Versus Performance](#txa932857_36)\n\n  \n \n74\n \n\n[Proposal 3: Ratification of the Selection of Independent Auditors](#txa932857_37)\n  \n \n78\n \n\n[Audit and Risk Committee Report](#txa932857_38)\n  \n \n79\n \n\n[Stock Ownership Information](#txa932857_39)\n  \n \n80\n \n\n[Five Percent Owners of Common Stock](#txa932857_40)\n\n  \n \n80\n \n\n[Stock Ownership of Directors, Board Nominees and Executive Management](#txa932857_41)\n\n  \n \n81\n \n\n[Annual Meeting Information](#txa932857_42)\n  \n \n82\n \n\n[2026 Annual Meeting of Stockholders—Questions & Answers](#txa932857_43)\n\n  \n \n82\n \n\n[2027 Annual Meeting and Stockholder Proposals](#txa932857_44)\n\n  \n \n87\n \n\n[Other Business and Information](#txa932857_45)\n\n  \n \n87\n \n\n##### Table of Contents\n\n \n\n \n\n \n \n  \n\n \n\n4\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n \n\n  \n\n \n\nProxy Statement Summary\n\nThis summary highlights information that is contained elsewhere in this Proxy Statement. You should carefully read this Proxy Statement in its entirety before voting, as this summary does not contain all of the information that you should consider. For more complete information regarding our business and its recent financial performance, you should review our Annual Report on Form 10-K for the fiscal year ended December 28, 2025, including the sections titled “Forward Looking Statements” and “Risk Factors”, which describe the risks and uncertainties related to any forward-looking statements included in this Proxy Statement.\n\n \n\n \n\nANNUAL MEETING OF STOCKHOLDERS\n\n \n \n \n\n  \n\n \n\nDATE & TIME:\n\nThursday, May 14, 2026\n\n11:30 a.m. Central Time\n\n  \n\nVIRTUAL MEETING SITE:\n\nwww.meetnow.global/MSSZRJ5\n\n \n\nRECORD DATE AND VOTING:\n\nMarch 16, 2026\n\nATI stockholders as of the record date are entitled to vote on the matters presented at the meeting. Each share of ATI common stock is entitled to one vote for each director nominee and one vote on each other matter presented.\n\n \n\n  \n\n \n\nMEETING AGENDA\n\n \n\n Proposal\n \n\n \n\nBoard’s voting\nrecommendation     \n\n \nPage reference\n \n  \n\n \n\n 1. Election of three directors\n\n \n\n \n\n \n\n FOR EACH NOMINEE\n\n \n\n \n\n \n\n11\n\n \n\n \n \n\n \n\n 2. Advisory vote to approve the compensation of our named executive officers\n\n \n\n \n\n \n\n FOR\n\n \n\n \n\n \n\n38\n\n \n\n \n \n\n \n\n 3. Ratification of Ernst & Young LLP as our independent auditors for 2026\n\n \n\n \n\n \n\n FOR\n\n \n\n \n\n \n\n78\n\n \n\n \n \n\n##### Table of Contents\n\n \n\n \n \n \n\n \n\n \n\nProxy Statement Summary\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n\n \n \n \n\n \n\n5 \n\n \n\nABOUT ATI\n\nATI is a global producer of high-performance materials and solutions for the global aerospace and defense markets, with emerging opportunities for specialty energy. We’re solving the world’s most difficult challenges through materials science. We partner with our customers to deliver extraordinary materials that enable their greatest achievements: their products fly higher and faster, burn hotter, dive deeper, stand stronger and last longer. Our proprietary process technologies, unique customer partnerships, and commitment to innovation deliver materials and solutions for today and the evermore challenging environments of tomorrow.\n\n2025 PERFORMANCE\n\n \n\nWe believe that the strategic and operational milestones we have achieved in recent years, and the targets we continue to pursue, are driving shareholder value creation and positioning our business for success in 2026 and beyond. The following charts illustrate ATI’s relative total shareholder return (“TSR”) compared to the S&P 500 in 2025 and since the beginning of 2023:\n\n \n\n \n\n \n\n \n\n \n\nWHAT’S NEW\n\n \n \n \n\n \n \nDuring 2025:\n \n\n◆\n\nKimberly A. Fields, ATI’s President and Chief Executive Officer, was appointed to succeed Robert S. Wetherbee as Board Chair\n\n \n\n◆\n\nTwo new independent directors with deep aerospace experience, Elizabeth H. Lund and Jean Lydon-Rodgers, joined our Board\n\n \n\n◆\n\nLeroy M. Ball was appointed to succeed J. Brett Harvey as Lead Independent Director\n\n \n\n◆\n\nJames Robert Foster was appointed to succeed Donald P. Newman as Chief Financial Officer, effective January 1, 2026\n\n \n\n◆\n\nAerospace and defense accounted for 68% of full-year sales\n\n \n\n◆\n\nWe returned $470 million to stockholders through our share repurchase program and saw our stock price more than double\n\n \n\n##### Table of Contents\n\n \n\n \n\n \n \n  \n\n \n\n6\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n \n\n  \n\n \n\nProxy Statement Summary\n\n \n\nPROPOSAL 1: ELECTION OF OUR DIRECTOR NOMINEES\n\nAt the Annual Meeting, Class III directors Kimberly A. Fields, Elizabeth H. Lund and David J. Morehouse each will stand for re-election to a three-year term. J. Brett Harvey and Robert S. Wetherbee will retire from our Board effective at the conclusion of the Annual Meeting.\n\nATI has a diverse, highly credentialed and highly experienced Board. Our directors, with their variety of tenure, qualifications, backgrounds, skills and experience contribute to a Board that is well-rounded and well-positioned to effectively oversee our business and promote the interests of our stakeholders.\n\n \n\n \n \n\n  \n \n \n\n  \n \n \n\n  \n \n \n\n  \n \n \n\n \nCommittees*\n \n \n \n\n \n \n \n\n  \n  \nName\n  \nAge\n  \nIndependent\n  \nPrincipal occupation\n \n  \n \nAudit &\nRisk\n  \nCLDC\n  \nNom\nGov\n \n  \n \nOther public\nboards\n \nDirector\nsince\n\n \n\n \n\n  \nKimberly A. Fields\n  \n56\n  \n \n  \nATI President and Chief Executive Officer; Board Chair-elect\n \n \n \n \n  \n \n  \n \n \n \n \n0\n \n2024\n\n  \nElizabeth H. Lund\n  \n61\n  \n\n \n\n \n\n  \nRetired executive at The Boeing Company\n \n \n \n∎\n  \n \n  \n \n \n \n \n0\n \n2025\n\n  \nDavid J. Morehouse\n  \n65\n  \n\n \n\n \n\n  \nSenior Advisor to the President at the Pittsburgh Steelers and retired President and Chief Executive Officer at the Pittsburgh Penguins\n \n \n \n \n  \n \n  \n∎\n \n \n \n0\n \n2015\n\n \n\n  \n\nLeroy M. Ball, Jr.\n\n \n\n  \n57\n  \n\n \n\n \n\n  \nBoard Chair and Chief Executive Officer of Koppers Holdings Inc.\n \n \n \n∎\n  \n \n  \n∎\n \n \n \n1\n \n2019\n\n  \nHerbert J. Carlisle\n  \n70\n  \n\n \n\n \n\n \n\n \n\n  \nRetired President and Chief Executive Officer of the National Defense Industrial Association and United States Air Force four-star general\n \n \n \n\n \n∎\n  \n∎\n  \n \n \n\n \n \n \n\n \n0\n \n2018\n\n  \nCarolyn Corvi\n  \n74\n  \n\n \n\n \n\n  \nRetired executive at The Boeing Company\n \n \n \n \n  \n∎\n  \n∎\n \n \n \n1\n \n2012\n\n  \nDavid P. Hess\n  \n70\n  \n\n \n\n \n\n  \nRetired Chief Executive Officer of Arconic Corporation and executive at United Technologies Corporation\n \n \n \n \n  \n∎\n  \n∎\n \n \n \n2\n \n2019\n\n  \nMarianne Kah\n  \n72\n  \n\n \n\n \n\n  \nRetired executive at ConocoPhillips\n \n \n \n∎\n  \n∎\n  \n \n \n \n \n0\n \n2019\n\n  \nJean Lydon-Rodgers\n  \n62\n  \n\n \n\n \n\n  \nRetired GE Aviation Services executive\n \n \n \n∎\n  \n \n  \n \n \n \n \n0\n \n2025\n\n  \n\nRuby Sharma\n\n \n\n  \n59\n  \n\n \n\n \n\n  \nRetired Partner at Ernst & Young LLP\n \n \n \n∎\n  \n \n  \n \n \n \n \n2\n \n2023\n\n \n\nAudit Committee Finacial Expert\n  \n∎ Chair\n \n∎ Member\n  \n\n  \n\n  \n\n  \n\n  \n\n  \n\n*  CLDC = Compensation and Leadership Development\n\n \n\n   Nom Gov = Nominating and Corporate Governance\n\n##### Table of Contents\n\n \n\n \n \n \n\n \n\n \n\nProxy Statement Summary\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n\n \n \n \n\n \n\n7 \n\n \n\nHighly Engaged Board Oversees Risk and Guides the Strategic Direction of Our Company\n\nThe ATI Board:\n\n \n\n◆\n \n\nactively oversees long-term strategic planning and capital allocation decisions\n\n \n\n◆\n \n\nregularly assesses and oversees management and mitigation of known and emergent risks to our business\n\n \n\n◆\n \n\nengages in thoughtful Board and senior management succession planning\n\n \n\n◆\n \n\nconducts annual self-assessment and adheres to robust stock ownership guidelines and a mandatory retirement age.\n\n \n\n \n\n*Excludes Brett Harvey and Robert Wetherbee, both of whom will retire from the Board at the conclusion of the Annual Meeting.\n\n##### Table of Contents\n\n \n\n \n\n \n \n  \n\n \n\n8\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n \n\n  \n\n \n\nProxy Statement Summary\n\n \n\nContinuing Director Skills and Experience Matrix\n\n \n\nExperience/ Skill\n \n%   \n \nRepresentation on current Board\n \n\nCybersecurity\n \n30%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nFinance/Accounting-focused Role\n \n30%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nLabor Relations\n \n30%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nEnvironmental/ Safety\n \n40%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nM&A/Activism\n \n50%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nInvestor Relations\n \n50%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nCorporate Responsibility/ESG\n \n50%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nTalent Development\n \n50%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nMarketing/Communications\n \n60%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nTechnology/lnnovation/R&D\n \n60%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nSitting/Past CEO\n \n60%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nPublic Company Governance\n \n60%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nEnterprise Risk Management\n \n70%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nIndustry Knowledge\n \n70%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nGovernment Relations\n \n70%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nOther Public Company Board(s)\n \n70%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nOther Sr. Exec. (e.g. CFO, COO)\n \n80%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nManufacturing/Ops/Logistics/Sales\n \n80%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nInternational\n \n100%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nFinancial Literacy\n \n100%  \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\n \n\n \n\n \n\n##### Table of Contents\n\n \n\n \n \n \n\n \n\n \n\nProxy Statement Summary\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n\n \n \n \n\n \n\n9 \n\n \n\nPROPOSAL 2: APPROVAL OF OUR EXECUTIVE OFFICER COMPENSATION\n\nAt the Annual Meeting, our stockholders will be asked to approve the compensation of our named executive officers (our “NEOs”) on a non-binding advisory basis. ATI’s executive compensation program is designed to support our long-term strategic vision and to align with our pay-for-performance philosophy. Our Compensation and Leadership Development Committee believes our executive compensation program should:\n\n \n\n◆\n \n\npay competitively by setting target compensation in line with peers and others with which ATI competes for talent;\n\n \n\n◆\n \n\nretain executives who are essential to driving ATI’s strategies and future growth;\n\n \n\n◆\n \n\nsupport ATI’s business strategy by tying incentive compensation to specific performance goals and strategic objectives; and\n\n \n\n◆\n \n\nalign with stockholder interests by putting substantial portions of compensation at risk.\n\nWe believe that our compensation program is easy to understand, performance-driven and appropriately aligned with stockholders’ interests. Our program:\n\n \n\n \n\nPLACES SIGNIFICANT\n\nEMPHASIS ON FINANCIAL\n\nRESULTS\n\n \n\n \n\n \n\nALIGNS WITH OUR\n\nBUSINESS STRATEGIES\n\nAND PERFORMANCE\n\n \n\n \n\n \n\nREFLECTS COMPETITIVE\n\nMARKET DATA AND\n\nPRACTICES\n\n \n\n◆  Executive officer short-term cash incentive awards are 90% contingent on ATI’s financial performance.\n\n \n\n◆  For 2025, 70% of each executive officer’s regular annual equity award was contingent on our relative total shareholder return\n\n \n\n \n\n \n\n◆  Long-term equity incentive awards incorporate 3-year and 4-year equity performance-based incentives that align with our strategies.\n\n \n\n◆  Executive officer equity awards are heavily weighted in favor of performance stock units.\n\n \n\n \n\n \n\n \n\n◆  Executive officer compensation levels are benchmarked/reviewed annually\n\n \n\n◆  Equity incentive awards use double-trigger change in control vesting\n\n \n\n◆  We maintain robust stock ownership guidelines\n\nAs the following charts illustrate, significant portion of the target compensation of our CEO and each of our other NEOs is subject to the achievement of rigorous performance goals and is therefore “at risk.”\n\n2025 Target Pay Mix\n\n \n\n \n\n \n\n    \n\nReflecting this clear commitment to paying for performance, our executive compensation programs garner strong stockholder support. Our Say on Pay proposals were overwhelmingly approved by more than 98% of the shares voted at our 2023, 2024 and 2025 Annual Meetings.\n\n \n\n##### Table of Contents\n\n \n\n \n\n \n \n  \n\n \n\n10\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n \n\n  \n\n \n\nProxy Statement Summary\n\n \n\nPROPOSAL 3: AUDITOR RATIFICATION\n\nAt the Annual Meeting, our stockholders will be asked to ratify the appointment of Ernst & Young LLP as our independent auditor for 2026. Our Audit and Risk Committee actively monitors our independent audit firm’s work and relationships to confirm their ongoing independence and to limit their services to audit and audit-related matters.\n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nProposal 1: Election of Directors Director Terms\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n11 \n\n \n\nProposal 1: Election of Directors\n\nOur Board of Directors has nominated Kimberly A. Fields, Elizabeth H. Lund and David J. Morehouse for re-election to the Board as Class III directors for three-year terms expiring in 2029.\n\nPlurality Voting: Directors are elected by a plurality of the votes cast. This means that the three nominees for election to the Board who receive the most “FOR” votes (among votes properly cast in person, electronically, telephonically or by proxy) will be elected.\n\nDirector Resignation Policy: While directors are elected by a plurality of the votes cast, our Bylaws require that, in an uncontested election, if any director nominee receives a greater number of votes “WITHHELD” from his or her election than votes “FOR” such election, that nominee must tender a resignation. The Nominating and Governance Committee of the Board is required to make recommendations to the Board regarding any such tendered resignation. The Board will act on the tendered resignation within 90 days from the certification of the vote and will publicly disclose its decision, including its rationale.\n\nOnly votes “FOR” or “WITHHELD” are counted in determining whether a plurality of votes have been cast in favor of a director nominee; abstentions are not counted for purposes of the election of directors. If you do not grant authority to vote with respect to the election of any one or more of the nominees, your shares will not be voted with respect to the applicable nominees. If you indicated you wish to WITHHOLD your vote for a particular nominee, your shares will be counted for purposes of determining whether there is a quorum and against that director nominee for purposes of our director resignation policy.\n\nIf a nominee becomes unable or unwilling to serve, the individuals designated as proxies will vote for a Board-designated substitute nominee, or the Board may reduce the number of directors. The Company has no reason to believe that any of the nominees for election will be unable or unwilling to serve.\n\nDIRECTOR TERMS\n\nOur directors are divided into three classes, and the directors in each class generally serve for three-year terms unless they retire or are unable to serve due to death or disability. The term of one class of directors expires each year at our annual meeting of stockholders. The Board may fill a current or anticipated vacancy by electing a new director to the same class as the director being replaced or by reassigning a director from another class. The Board also may create a new director position in any class and elect a director to hold the newly created position.\n\nMandatory Retirement Policy: Our Corporate Governance Guidelines mandate that ATI directors retire from the Board no later than the conclusion of the first Annual Meeting of Stockholders that occurs after their 75th birthday. If a director will reach the age of 75 during his or her next upcoming term, the Nominating and Governance Committee takes that fact into account in determining whether to recommend nomination of the director for re-election.\n\nOUR DIRECTOR NOMINATION PROCESS\n\nThe Board is responsible for recommending director nominees to the stockholders and for selecting directors to fill vacancies between stockholder meetings. The Nominating and Governance Committee recommends candidates to the Board.\n\nThe Nominating and Governance Committee considers director candidates identified by external search firms engaged by the Committee, sitting directors, senior management and stockholders, among other sources. The Committee will evaluate stockholder-recommended candidates on the same basis as candidates identified through other sources. Stockholder recommendations should be sent to ATI’s Corporate Secretary, who will forward the information to the Nominating and Governance Committee.\n\nThe Board has, at times, engaged an external search firm to facilitate nationwide candidate searches as part of its refreshment efforts. The Committee believes that a wide-ranging and robust search is the best way to identify those candidates who most closely meet the experience, skill and other criteria established by the Committee as necessary or desirable additions to the Board. Elizabeth Lund and Jean Lydon-Rodgers joined our Board following a national search facilitated by an external search firm.\n\nWe allow a stockholder or group of up to 20 stockholders owning an aggregate of 3% or more of our outstanding common stock for at least three years to nominate and include in our proxy materials director nominees constituting up to 20% of the number of directors then in office or two nominees, whichever is greater, provided the stockholders and nominees otherwise satisfy the requirements of our Bylaws.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n12\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nProposal 1: Election of Directors Our Director Nomination Process\n\n \n\nCriteria for Director Nominees\n\nOur Board engages, as appropriate, in refreshment efforts that focus on the significant characteristics and skill sets it considers most relevant to its continued effective and efficient oversight of our business and the risks that ATI faces.\n\nIn evaluating the needs of the Board, the Nominating and Governance Committee considers the qualifications and past contributions to the Board of sitting directors and consults with our Board Chair, Chief Executive Officer, and other members of the Board (including as part of the Board’s annual self-evaluation) and executive management. Director candidates generally are selected on the basis of the following criteria:\n\n \n\n◆\n \nbusiness or professional experience;\n\n \n\n◆\n \nrecognized achievement in their respective fields;\n\n \n\n◆\n \nhigh standards of integrity, judgment and independence;\n\n◆\n \nability to devote sufficient time to the affairs of ATI;\n\n \n\n◆\n \nability to represent the interests of all stockholders; and\n\n \n\n◆\n \nthe skills and experience they add to the Board’s overall competencies.\n\n \n\n \n\nBoard Diversity is one of many criteria considered by the Board when evaluating candidates. A key factor in identifying director nominees is our interest in building a cognitively diverse board representing a wide breadth of experience and perspectives. Our Board’s diversity of expertise and experience positions it well to effectively oversee our business in the context of the complex and rapidly evolving markets and geopolitical climate in which ATI operates. Additionally, ATI has long been recognized for the consistently strong representation of women on our Board.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nProposal 1: Election of Directors Our 2026 Director Nominees and Continuing Directors\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n13 \n\n \n\nOUR 2026 DIRECTOR NOMINEES AND CONTINUING DIRECTORS\n\nWe introduce our 2026 nominees and continuing directors below. All of our directors bring a wealth of executive leadership, board service and other experience to our Board.\n\nOur Board determined that each of the three director nominees meets our criteria for directors and that Ms. Lund and Mr. Morehouse qualify as independent directors under applicable rules and regulations. Mr. Wetherbee, who currently serves as Executive Chair and is a Class II Director, and Mr. Harvey, who is currently serves as our Lead Independent Director and is a Class III Director, will retire from our Board at the conclusion of the Annual Meeting.\n\n \n\nNominees – Class III – Term to Expire at the 2029 Annual Meeting\n\n \n\n  \n\nKimberly A. Fields\n\n \n\n \n\n  \n\n  \n\n \n\nDirector since 2024\n\n \n\nAge 56; Board Chair effective May 14, 2026\n\n \n\n  \n \n\n \n\nMs. Fields became ATI’s President and Chief Executive Officer on July 1, 2024, and has been appointed Board Chair effective at the conclusion of the Annual Meeting. She became President and Chief Operating Officer in June 2023, having served as Executive Vice President and Chief Operating Officer from January 2022 to June 2023, as Executive Vice President, AA&S and HPMC throughout 2021, and as Executive Vice President, Advanced Alloys & Solutions from April 2019 to December 2020. She joined ATI in April 2019 after serving as Group President at IDEX Corporation since 2015. Previously, Ms. Fields served as Executive Vice President for the integrated global steel producer EVRAZ, where she had full responsibility for all activities for the $2 billion North American Flat Products business. Prior to that, Ms. Fields was General Manager of Industrials for GE Energy, with global responsibility for growing GE’s penetration in metals, petrochemicals and mining segments, after holding a series of leadership positions with Alcoa, Inc., The Boston Consulting Group and Owens Corning Fiberglass.\n \n\n \n\n \n\nSkills and Qualifications\n\nMs. Fields’s qualifications include her extensive senior leadership experience, operational and industry-specific knowledge, and strategic planning expertise.\n\n \n\nPast Directorships:\n\n◆\n\nSilgan Holdings, Inc.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n14\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\n \n\nProposal 1: Election of Directors Our 2026 Director Nominees and Continuing Directors\n\n \n\n  \n\nElizabeth H. Lund\n\n \n\n \n\n  \n\n  \n\n \n\nDirector since 2025\n\n \n\nAge 61\n\n \n\n  \n \n\n \n\nMs. Lund retired from The Boeing Company in March 2025 following a 34-year career, having most recently served as Senior Vice President of Quality for Boeing Commercial Airplanes and as Chair of Boeing’s Enterprise Quality Operations Council. From 2021 to 2024, she was Senior Vice President, Airplane Programs, with responsibility for production and delivery across all commercial aircraft, and from 2019 to 2021, served as Vice President and General Manager, Supply Chain. overseeing 3,000 suppliers in 41 countries. Earlier in her career, Ms. Lund held numerous executive leadership positions in engineering, program management, manufacturing and supplier management across Boeing’s Commercial Airplanes business. At Boeing, she drove major turnarounds and implemented enterprise-wide safety and quality reforms with the Federal Aviation Administration. Ms. Lund received the Women in Aerospace Outstanding Achievement Award in 2015.\n \n\n \n\n \n\nBoard Committees:\n\n◆\n\nAudit and Risk\n\n \n\nSkills and Qualifications:\n\nMs. Lund’s qualifications include her extensive senior leadership experience and operational and aerospace industry-specific knowledge.\n\n \n\n  \n\nDavid J. Morehouse\n\n \n\n \n\n  \n\n  \n\n \n\nDirector since 2015\n\n \n\nAge 65\n\n \n\n  \n \n\n \n\nMr. Morehouse was appointed Senior Advisor to the President of the Pittsburgh Steelers in August 2022, following his retirement from his prior role as Chief Executive Officer and President of Pittsburgh Penguins LLC, which owns and operates the Pittsburgh Penguins National Hockey League team. He served as President of the Pittsburgh Penguins from 2007 to 2010 and as Chief Executive Officer from 2010 to April 2022. Mr. Morehouse joined the Pittsburgh Penguins in 2004 as a consultant for special projects, including the construction of the team’s current arena. He holds a master’s degree from Harvard’s John F. Kennedy School of Government and has extensive government relations experience, having previously worked in the Clinton administration, at the Pentagon, and on four presidential campaigns.\n \n\n \n\n \n\nBoard Committees:\n\n◆\n\nNominating and Governance\n\n \n\nSkills and Qualifications:\n\nMr. Morehouse’s qualifications include his leadership, strategic planning and development, operations, branding and marketing, and extensive government relations experience.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\n \n\nProposal 1: Election of Directors Our 2026 Director Nominees and Continuing Directors\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n15 \n\n \n\nContinuing Directors – Class I – Term to Expire at the 2027 Annual Meeting\n\n \n\n  \n\nHerbert J. Carlisle\n\n \n\n \n\n  \n\n  \n\n \n\nDirector since 2018\n\n \n\nAge 70\n\n \n\n  \n \n\n \n\nGeneral Carlisle served as President and Chief Executive Officer of the National Defense Industrial Association (NDIA) from March 2017 to April 2022, following a 39-year career in the United States Air Force, from which he retired as a four-star general. His last Air Force assignment was as Commander, Air Company Command at Langley Air Force Base in Virginia. Prior to that, he was the Commander of the Pacific Air Forces, the air component Commander for the U.S. Pacific Command, and served as executive director of Pacific Air Combat Operations staff, Joint Base Harbor in Hawaii, following various operational and staff assignments throughout the Air Force, including as chief of air operations, U.S. Central Command Forward in Riyadh, Saudi Arabia. During that time, General Carlisle participated in Operation Restore Hope in Somalia. He also served as deputy director and, later, as director of legislative liaison at the Office of the Secretary of the Air Force.\n\n \n\n \n\n \n\n \n\nBoard Committees:\n\n◆\n\nAudit and Risk\n\n◆\n\nCompensation and Leadership Development\n\n \n\nSkills and Qualifications:\n\nGeneral Carlisle’s qualifications include his executive leadership experience as a senior military official, his legislative and government experience, and his experience and knowledge in the aerospace and defense fields.\n\n \n\nCurrent Directorships:\n\n◆\n\nElbit Systems of America\n\n◆\n\nThe Entwistle Company\n\n◆\n\nCrew Training International\n\n \n\n  \n\nDavid P. Hess\n\n \n\n \n\n  \n\n  \n\n \n\nDirector since 2019\n\n \n\nAge 70\n\n \n\n  \n \n\n \n\nMr. Hess has 40 years of experience in the aerospace industry, including 38 at United Technologies Corporation, where he served as Executive Vice President and Chief Customer Officer for UTC Aerospace from January 2016 until his retirement in January 2017. From 2009 to 2014 he was President of Pratt & Whitney, a subsidiary of UTC, responsible for the company’s global operations in the design, manufacture and service of engines for commercial and military aircraft. Most recently, Mr. Hess served as a board member for Arconic Corporation from March 2017 to May 2019, and as Arconic’s Chief Executive Officer from April 2017 to January 2018. Mr. Hess was a 10-year member of the Aerospace Industries Association Board of Governors Executive Committee and is a fellow of the Royal Aeronautical Society.\n \n \n \n  \n \n\nBoard Committees:\n\n◆\n\nNominating and Governance\n\n◆\n\nCompensation and Leadership Development\n\n \n\nSkills and Qualifications:\n\nMr. Hess’s qualifications include his extensive aerospace background and executive leadership experience, including as a former Chief Executive Officer.\n\n \n\nCurrent Directorships:\n\n◆\n\nWoodward, Inc.\n\n◆\n\nSouthwest Airlines Co.\n\n \n\nPast Directorships:\n\n◆\n\nArconic Corporation\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n16\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\n \n\nProposal 1: Election of Directors Our 2026 Director Nominees and Continuing Directors\n\n \n\n \n\n  \n\nMarianne Kah\n\n \n\n \n\n  \n\n  \n\n \n\nDirector since 2019\n\n \n\nAge 72\n\n \n\n  \n \n\n \n\nMs. Kah is a global energy and raw materials markets expert with extensive experience in board-level strategic planning and risk analysis. She served as Chief Economist for ConocoPhillips, an oil and gas exploration and production company, for more than 20 years until her retirement in 2017, developing market outlooks, risk assessments and scenario plans that drove corporate strategy. She currently serves as an adjunct senior research scholar and Advisory Board member of Columbia University’s Center on Global Energy Policy. In 2021, she received certification by Ceres and University of California Berkeley School of Law in “ESG: Navigating the Board’s Role,” and in 2024 received certification in Cybersecurity Oversight from the Software Engineering Institute at Carnegie Mellon University and the National Association of Corporate Directors. She is Past President of the U.S. Association for Energy Economics and previously co-led the Energy Roundtable for the National Association for Business Economics.\n\n \n\n \n\n \n\n \n\nBoard Committees:\n\n◆\n\nAudit and Risk\n\n◆\n\nCompensation and Leadership Development\n\n \n\nSkills and Qualifications:\n\nMs. Kah’s qualifications include her energy markets experience and expertise, her leadership skills and past role as a senior leader of a global public company, and her extensive strategic planning background.\n\n \n\nPast Directorships:\n\n◆\n\nPGS ASA\n\n \n\n  \n\nRuby Sharma\n\n \n\n \n\n  \n\n  \n\n \n\nDirector since 2023\n\n \n\nAge 59\n\n \n\n  \n \n\n \n\nMs. Sharma was Managing Partner of RNB Strategic Advisors, a strategic advisory firm, from September 2018 to August 2022. She previously served as a Partner at Ernst & Young LLP from 2002 until her retirement in December 2017. Prior to that, Ms. Sharma was Senior Manager of Forensic and Litigation Services at Arthur Anderson. She previously served as a board trustee for the National Ascend Organization and as a member of the Asia Society Business Council.\n \n \n \n  \n \n\nBoard Committees:\n\n◆\n\nAudit and Risk (Chair)\n\n \n\nSkills and Qualifications:\n\n◆\n\nMs. Sharma’s qualifications include her experience in senior leadership positions and her financial and public company accounting expertise.\n\n◆\n\nAudit Committee Financial Expert\n\n \n\nCurrent Directorships:\n\n◆\n\nSoundThinking, Inc.\n\n◆\n\nS&C Electric Company\n\n◆\n\nSouthwest Gas Holdings, Inc.\n\n \n\nPast Directorships:\n\n◆\n\nBowflex, Inc.\n\n◆\n\nAspira Women’s Health\n\n◆\n\nPenn Medicine Princeton Health\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\n \n\nProposal 1: Election of Directors Our 2026 Director Nominees and Continuing Directors\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n17 \n\n \n\nContinuing Directors – Class II – Term to Expire at the 2028 Annual Meeting\n\n \n\n  \n\nLeroy M. Ball, Jr.\n\n \n\n \n\n  \n\n  \n\n \n\nDirector since 2019; Lead Independent Director, effective May 14, 2026\n\n \n\nAge 57\n\n \n\n  \n \n\n \n\nMr. Ball has been the Board Chair and Chief Executive Officer of Koppers Holdings Inc., a leading integrated global provider of treated wood products, wood treatment chemicals and carbon compounds, since May 2025, having served as its Chief Executive Officer from January 2024 to May 2025 and as President and Chief Executive Officer from January 2015 through December 2023. Prior to that, he held other executive leadership roles at Koppers, serving as both Chief Operating Officer and Chief Financial Officer. Before joining Koppers, Mr. Ball served as the Senior Vice President and Chief Financial Officer of Calgon Carbon, Inc., a provider of services, products and solutions for purifying water and air, from 2002 to 2010.\n\n \n\n \n\n \n\n \n\nBoard Committees:\n\n◆\n\nAudit and Risk\n\n◆\n\nNominating and Governance (Chair)\n\n \n\nSkills and Qualifications:\n\n◆\n\nMr. Ball’s qualifications include his experience in senior leadership positions, including his current role as a sitting CEO, and his operational, financial, and public company accounting expertise.\n\n◆\n\nAudit Committee Financial Expert\n\n \n\nCurrent Directorships:\n\n◆\n\nKoppers Holdings Inc.\n\n◆\n\nKoppers, Inc. (a subsidiary of Koppers Holdings Inc.)\n\n \n\n  \n\nCarolyn Corvi\n\n \n\n \n\n  \n\n  \n\n \n\nDirector since 2012\n\n \n\nAge 74\n\n \n\n  \n \n\n \n\nMs. Corvi led a 34-year career with The Boeing Company. She most recently served as Vice President, General Manager of Airplane Programs, Boeing Commercial Airplanes, a position she held from 2005 until her retirement in 2008.\n \n \n \n  \n \n\nBoard Committees:\n\n◆\n\nCompensation and Leadership Development (Chair)\n\n◆\n\nNominating and Governance\n\n \n\nSkills and Qualifications:\n\nMs. Corvi’s qualifications include her extensive senior leadership experience in the aerospace industry and her knowledge of and experience in manufacturing.\n\n \n\nCurrent Directorships:\n\n◆\n\nHyster-Yale Materials Handling, Inc.\n\n \n\nPast Directorships:\n\n◆\n\nUnited Continental Holdings, Inc.\n\n◆\n\nGoodrich Corporation\n\n◆\n\nContinental Airlines, Inc.\n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n18\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\n \n\nProposal 1: Election of Directors Our 2026 Director Nominees and Continuing Directors\n\n \n\n \n\n  \n\nJean Lydon-Rodgers\n\n \n\n \n\n  \n\n  \n\n \n\nDirector since 2025\n\n \n\nAge 62\n\n \n\n  \n \n\n \n\nMs. Lydon-Rodgers retired in 2021 following a 34-year career with GE Aviation, having most recently served as President and Chief Executive Officer of GE Aviation Services, the company’s global aftermarket services division, from 2016 until 2021. From 2009 to 2016, she was President and Chief Executive Officer of GE Aviation Military Systems, with responsibility for the development, production, and aftermarket support of 24,000 fixed-wing, helicopter and marine engines for the U.S. Department of Defense and international military customers. Earlier in her career, Ms. Lydon-Rodgers held a series of executive leadership positions with GE Aviation, including as Vice President of the F136 Engine Program at GE Aviation and President and Chair of the Board of the GE Rolls-Royce Fighter Engine Team, leading a joint venture between GE and Rolls-Royce responsible for the development of the Joint Strike Fighter F136 Propulsion System. Ms. Lydon-Rodgers has been recognized for her industry leadership, including through her service on the FAA/DOT Women in Aviation Advisory Board and as a recipient of the Distinguished Stateswoman of Aviation Award from the National Aeronautic Association in 2021.\n \n\n \n\n \n\nBoard Committees:\n\n◆\n\nAudit and Risk\n\n \n\nSkills and Qualifications\n\nMs. Lydon-Rodgers’ qualifications include her extensive senior leadership and operational and aerospace industry-specific knowledge.\n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nProposal 1: Election Of Directors Director Skills and Experience\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n19 \n\n \n\nContinuing Director Skills and Experience*\n\n  \n \n\n \n \n\n \n \n\n \n \n\n \n \n\n \n \n\n \n \n\n \n \n\n \n \n\n \n \n\n \n\nCEO EXPERIENCE gives our Board strong leadership and experience across a range of corporate governance, strategic planning, finance, operational, and management and succession planning matters.\n \n∎\n\n \n \n∎\n \n\n \n\n \n \n\n \n \n \n \n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n \n \n \n \n \n \n \n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n \n \n \n\nINDUSTRY KNOWLEDGE provides valuable, in-depth knowledge of our industry and/or the end markets we serve, with a detailed understanding of our business challenges and opportunities.\n \n \n \n \n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n \n \n \n \n \n \n \n\nMANUFACTURING/OPERATIONAL experience gives our Board a practical understanding of the development and implementation of our business plan and the risks and opportunities that can impact our operations and strategies.\n \n∎\n \n\n \n\n \n \n\n \n \n \n \n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n \n \n \n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\nFINANCIAL LITERACY provides our Board with the financial acumen necessary to inform its oversight of our financial performance and reporting, internal controls and long-term strategic planning.\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\nTECHNOLOGY/INNOVATION/R&D experience brings important perspectives that support our development of innovative products and technologies and the Board’s risk oversight function.\n \n \n \n \n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n \n \n \n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n \n \n \n\nTALENT DEVELOPMENT experience enables directors to make important contributions to our efforts to engage in robust succession planning; attract, motivate and retain high-performing employees; and interact effectively with our workforce.\n \n \n \n \n \n \n \n \n \n \n \n \n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n \n \n \n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\nMARKETING/COMMUNICATIONS/INVESTOR RELATIONS experience helps guide our strategic efforts to develop new and existing markets and to communicate effectively with our stakeholders.\n \n∎\n \n\n \n\n \n \n\n \n \n \n \n \n \n \n \n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n \n \n \n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\nGOVERNMENT RELATIONS experience gives directors a deep understanding of the regulatory environment in which we operate.\n \n \n \n \n \n∎\n\n \n \n \n \n \n \n \n \n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nM&A experience is relevant to our long-term strategic planning and assessment of strategic growth opportunities.\n \n∎\n\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n∎\n\n \n \n \n \n \n \n \n \n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nINTERNATIONAL experience is relevant to the global nature of our business and contributes to our Board’s ability to assess business risks and opportunities in the context of rapidly evolving geopolitical conditions.\n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n \n \n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nENTERPRISE RISK MANAGEMENT expertise adds depth and structure to the Board’s exercise of its risk oversight function.\n \n∎\n\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n \n∎\n\n \n\nENVIRONMENTAL/SAFETY experience enhances the Board’s risk oversight capabilities.\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n∎\n\n \n \n \n \n \n \n∎\n\n \n \n \n \n \n \n∎\n\n \n \n∎\n\n \n\nCYBERSECURITY experience is relevant to the global nature of our business and to our long-term strategic planning.\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n \n \n \n \n \n \n \n \n \n \n \n \n∎\n \n\n \n\n \n \n\nCORPORATE GOVERNANCE/CORPORATE RESPONSIBILITY experience supports our emphasis on strong Board and management accountability, transparency, protection of stockholder interests, and long-term value creation.\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n \n∎\n \n\n \n\n \n \n\n* Based on skills self-identified by each member of our Board.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n20\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nOur Corporate Governance Our Commitment to Integrity, Corporate Governance and Sustainability\n\n \n\nOur Corporate Governance\n\nOur Board of Directors oversees management of our business for the long-term benefit of our stockholders and other stakeholders. Our corporate governance practices are designed to maintain high standards of oversight, compliance, integrity and ethics, while promoting growth in long-term stockholder value.\n\nWe are committed to a strong self-governance program. Each year, we review our corporate governance and compensation policies and practices and engage with our stockholders. In our ongoing effort to consistently align our corporate governance with best practices, we consider suggestions from our stockholders, along with developments and evolving trends reflected in the standards established by proxy advisory firms and in the policies, practices and disclosures of other public companies.\n\nOUR COMMITMENT TO INTEGRITY, CORPORATE GOVERNANCE AND SUSTAINABILITY\n\n \n\n \n\n \n\nATI is committed to conducting its business in an honest, ethical and lawful manner. We do the right things, the right way, every day.\n\n \n\n \n\n \n\nWe are on a relentless pursuit to protect the health and safety of our employees, the environment, and our communities. We support sustainable development and consistently work to improve our operations to the benefit of our stockholders, employees, customers and local communities.\n\n \n\n \n\n \n\nWe are committed to maintaining a collaborative workplace where employees are supported and respected, free of harassment abusive conduct and bullying, and where all employees can do their best work.\n\n \n\n \n\n \n\nWe value our reputation. We strive to create value for our stakeholders while operating as a good corporate citizen.\n\n \n\n \n\n \n\nWe are also committed to providing information in our financial reporting that is accurate, complete, objective, and auditable and reflects a true picture of our business. We have a robust system of internal controls.\n\n \n\n \n\n \nWe take these commitments seriously. Our management and our Board have instilled an enterprise culture that supports and honors the policies we undertake to further our commitments.\n\n \n\n \n\nCorporate Governance Information on Our Website\n\n \n\n \n\nThe following governance documents are available on our website atimaterials.com, at “Investors – Corporate Governance”:\n\n \n\n◆\n \n\nCorporate Governance Guidelines\n\n \n\n◆\n \n\nATI Code of Conduct\n\n \n\n◆\n \n\nBoard Committee Charters\n\n \n\n◆\n \n\nCertificate of Incorporation and Bylaws\n\nPaper copies can be obtained by writing to the Corporate Secretary, ATI Inc., 2021 McKinney Avenue, Dallas, TX 75201.\n\nAdditionally, our current Corporate Responsibility Report and TCFD Report are available at ATImaterials.com/aboutati/Pages/safety-sustainability. For more information, see page 36 of this Proxy Statement.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nOur Corporate Governance ATI Corporate Governance at a Glance\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n21 \n\n \n\nATI CORPORATE GOVERNANCE AT A GLANCE\n\nPresented below are some highlights of the ATI corporate governance program. You can find details about these and other corporate governance policies and practices within this Proxy Statement.\n\n \n\n \n\nBoard Independence\n\n◆\n\nNine out of ten continuing directors are independent\n\n \n\n◆\n\nIndependent directors meet in regularly scheduled executive sessions without management present.\n\n \n\n◆\n\nStockholders can communicate with our independent directors through our Lead Independent Director.\n\n \n\n \n\n  \n\n \n\n \n\nAccountability to Stockholders\n\n◆\n\nEngagement with Stockholders. We actively reach out to our stockholders through our annual engagement program and communicate with them on important compensation, governance and sustainability Issues.\n\n \n\n◆\n\nProxy Access. We allow a stockholder or group of up to 20 stockholders owning an aggregate of 3% or more of our outstanding common stock for at least three years to nominate and include in our proxy materials director nominees constituting up to 20% of the number of directors then in office or two nominees, whichever is greater, provided the stockholders and nominees otherwise satisfy the requirements of our Bylaws.\n\n \n\n◆\n\nMajority Voting/Director Resignation Policy. Any nominee for director in an uncontested election who receives a greater number of votes “withheld” than votes “for” his or her election must promptly tender a resignation for the Board’s consideration.\n\n \n\n \n\nBoard Composition\n\n◆\n\nOur Board has a diverse mix of skills, experience and background. Six of our continuing directors are women and one is a person of color.\n\n \n\n◆\n\nOur Board regularly assesses its performance and can adjust the number of directors according to need or as the opportunity arises to enhance the overall mix of skills and experience represented on our Board.\n\n \n\n◆\n\nWe have a mandatory retirement age of 75.\n\n \n\n \n \n\n \n\n \n\n \n\n \n\nIndependent Board Committees\n\n◆\n\nAll of the Board’s standing committees are composed entirely of independent directors, and each has a written charter that is reviewed and reassessed annually and is posted on our website.\n\n \n\n \n\n \n\n \n\n \n\nSelf-Evaluations\n\n◆\n\nWe have an annual self-evaluation process for the Board and for each standing committee of the Board.\n\n \n \n\n \n\n \n\n \n\n \n\nRisk Oversight\n\n◆\n\nOur full Board is ultimately responsible for risk oversight and has designated committees to assist in the oversight of certain key risks.\n\n \n\n◆\n\nOur Board oversees management as it fulfills its responsibilities for assessing and mitigating risks and for taking appropriate risks.\n\n \n\n \n\n \n\n \n\nDirector and NEO Stock Ownership\n\n◆\n\nEach director is expected to own ATI common stock with a value equivalent to at least four times the amount of their annual cash retainer.\n\n \n\n◆\n\nExecutives are expected to own a substantial amount of ATI common stock, including a threshold of six times base salary for the President and CEO.\n\n \n\n \n \n\n \n\n \n\n \n\n \n\nSuccession Planning\n\n◆\n\nThe Board actively monitors our management succession plans and receives regular updates on employee recruitment, engagement, culture and retention matters. At least annually, the Board reviews senior management succession and development plans.\n\n \n\n◆\n\nThe Board evaluates matters related to Board succession and the processes by which we identify additional directors with strong and diverse experience.\n\n \n\n \n\n \n\n \n\nEthics/Corporate Responsibility\n\n◆\n\nOur Corporate Governance Guidelines, Code of Conduct, Supplier Expectations and Supply Chain Policies, TCFD Report and annual Corporate Responsibility Report are all available on our website.\n\n \n\n◆\n\nOur Code of Conduct applies to all of our directors, officers and employees, and our active ethics and compliance program requires each of them to participate in training and make annual certifications.\n\n \n\n◆\n\nWe expect each of our suppliers to comply with our Supplier Expectations and Supply Chain Policies, including policies with respect to business conduct and ethics, the sourcing of conflict minerals, and policies to combat bribery, corruption and human trafficking.\n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n22\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\n \n\nOur Corporate Governance Our Board and its Role\n\n \n\nOUR BOARD AND ITS ROLE\n\nOur Board Leadership Structure\n\nOur Board has the flexibility to determine whether it is in the best interests of ATI and its stockholders to separate or combine the roles of Board Chair and Chief Executive Officer at any given time. In making that determination, the Board assesses whether the roles should be separated or combined based on its evaluation of the existing composition of the Board and the circumstances at the time.\n\nMs. Fields joined our Board in February 2024 and became ATI’s President and Chief Executive Officer in July 2024, after serving in various executive leadership roles since 2019, including as President and Chief Operating Officer since June 2023. She has been appointed to succeed Mr. Wetherbee, our current Executive Chairman, as Board Chair, effective at the conclusion of the 2026 Annual Meeting, when Mr. Wetherbee will retire from our Board. Mr. Harvey has served as Lead Independent Director since 2021. Mr. Ball has been appointed to succeed Mr. Harvey as Lead Independent Director, effective at the conclusion of the 2026 Annual Meeting, when Mr. Harvey is retiring from our Board.\n\nWhy We Transitioned to a Combined Chair and CEO role\n\n \n\n \n\nOur Board believes that combining the roles of Board Chair and Chief Executive Officer will promote unified leadership and direction for the Company and will facilitate the efficient implementation of our strategies to create shareholder value over the long term. Additionally, the Board believes that Ms. Fields, serving in both capacities, will effectively bridge communication between the Board and our management.\n\nOur Board’s ability to maintain appropriate independent oversight of our business strategies and activities is enhanced by ATI’s existing strong governance structures and policies, such as:\n\n \n\n◆\n \n\nmaintaining a Lead Independent Director with significant responsibilities;\n\n \n\n◆\n \n\nappointing only independent directors to the standing committees of the Board; and\n\n \n\n◆\n \n\nregularly scheduling executive sessions of the independent directors.\n\n \n\n \n\n \n\n \n\n \n \n\n \n\n OUR LEAD INDEPENDENT DIRECTOR\n\n \n\n \n\n \n\n \n \n\n \n\n \n\nLeroy M. Ball has been appointed to serve as our Lead Independent Director effective at the conclusion of the Annual Meeting, succeeding J. Brett Harvey who is retiring. The Lead Independent Director is the principal liaison between the independent directors and the senior management on Board-wide issues.\n\n \n\nRole and Responsibilities:\n\n \n\n \n\n \n\n \n\n◆\n\nPreside, in the absence of the Chair, at Board meetings, including executive sessions of the independent directors;\n\n \n\n◆\n\nCall meetings of the independent directors as appropriate;\n\n \n\n◆\n\nFacilitate communication among independent directors between meetings, when appropriate;\n\n \n\n◆\n\nAdvise the Chair and CEO regarding schedules, agendas and the quantity, quality and timeliness of information for the Board;\n\n \n\n \n\n◆\n\nServe as a contact for stockholders wishing to communicate with the Board other than through the Chair, when appropriate;\n\n \n\n◆\n\nCommunicate with other external constituencies, as needed;\n\n \n\n◆\n\nAdvise and consult with the Chair and CEO on governance matters and Board performance; and\n\n \n\n◆\n\nGenerally serve as a resource for the Chair and CEO.\n\n \n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nOur Corporate Governance Our Board and its Role\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n23 \n\n \n\nIndependent Committees\n\n \n\n \n\nOur Board has three standing committees, its: Audit and Risk Committee; Nominating and Governance Committee; and Compensation and Leadership Development Committee. Each committee is composed entirely of independent directors, and each has a written charter that describes its responsibilities. These charters, which are reviewed annually and updated as needed, are available on the “Investors—Corporate Governance” pages of our website. For more information, see “The Role of Our Board” and “Board Committees” below.\n\nThe Role of Our Board\n\nOur Board is elected by our stockholders to safeguard their interests through oversight of management and the good faith exercise of its members’ business judgment. At the same time, our Board believes that the long-term interests of ATI are advanced by recognizing the concerns of other constituencies, including employees, customers, suppliers and the communities in which we operate. Accordingly, while not involved in our day-to-day operations, our Board actively oversees matters of key importance to the overall conduct of our business, including our financial performance and expectations, development and implementation of our strategic plans, capital structure and allocation, matters impacting our corporate governance and culture, and the identification and mitigation of known and emergent enterprise risks and opportunities, including those pertaining to environmental, workforce and community safety and sustainability.\n\nKey Oversight Responsibilities of the Board\n\n \n\n \n\n \n\nStrategy\n\n \n\n◆ The Board oversees and lends perspective to management’s development and execution of near, medium and longer-term strategy\n\n \n\n◆ Strategic considerations are an integral part of every Board meeting and foundational to deliberations and decision-making processes of our Board and its committees\n\n \n\n \n\n \n\n  \n\n \n\nLeadership\n\n \n\n◆ The Board oversees succession planning and talent development for senior executive positions\n\n \n\n◆ The Board’s Compensation and Leadership Development Committee has primary responsibility for overseeing succession planning for the CEO position\n\n \n\n  \n\n \n\nRisk\n\n \n\n◆ The Board oversees risk management\n\n \n\n◆ The Board’s standing committees regularly meet, report to the full Board and play key roles, as defined in their respective charters, in the Board’s exercise of its oversight function\n\n \n\nStrategy Oversight\n\n \n\n \n\nOur directors oversee and, leveraging their broad array of backgrounds, experience and expertise, lend perspective and insight to, management’s development and execution of near, medium and longer-term strategy.\n\n \n\nLeadership Development and Succession Oversight\n\n \n\n \n\nWith the support of the Compensation and Leadership Development Committee and its independent compensation consultants, our Board actively monitors our comprehensive senior leadership development and succession plans to support the team’s ongoing performance, resilience and diversity of background, skills and experience. Leadership development, engagement, retention and succession matters are regularly addressed during Board meetings throughout the year and during the Board’s annual strategy meeting. Additionally, the Board conducts an in-depth review of senior management development and succession plans at least annually.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n24\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nOur Corporate Governance Our Board and its Role\n\n \n\nRisk Oversight\n\n \n\n \n\nUnderstanding the risks and opportunities facing the Company is fundamental to the Board’s ability to effectively exercise its oversight function and promote stakeholder interests. We view the consideration of enterprise risk — the specific financial, operational, business and strategic risks that the Company faces — as integral to our decision-making processes at both the Board and management level. We consistently seek to identify potential risks and to balance risk mitigation with a level of risk tolerance that enables us to pursue opportunities to grow stockholder value as they arise. We implemented an Enterprise Risk Management program that serves as a key vehicle for informing our Board’s understanding of the most significant risks facing our business and the steps management is taking to mitigate those risks. The ERM further enables the Board to assess the effectiveness of our risk mitigation strategies on an ongoing basis and to identify emerging risks that may impact our business in the future.\n\n \n\nThis approach is intended to foster open dialogue and to assist our Board in understanding critical risks to our business and strategy, appropriately allocating oversight responsibility among its standing committees, and evaluating the operation of the Company’s enterprise risk management processes.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nOur Corporate Governance Our Board and its Role\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n25 \n\n \n\nCybersecurity Risk Management and Oversight\n\nOur Board is actively engaged in the oversight of our digital technology risk management and cybersecurity programs. As part of its regular oversight, the Audit and Risk Committee assists the Board in overseeing ATI’s digital technology and cybersecurity risks. Our Chief Digital and Information Officer leads development and execution of our digital technology strategy, as well as our efforts to address and mitigate digital technology risks. Our Chief Information Security Officer oversees our cybersecurity program. The Audit and Risk Committee receives quarterly reports from our Chief Digital and Information Officer on ATI’s cybersecurity risk profile, enterprise cybersecurity program, and other digital technology risks. For additional information, see page 16 of ATI’s 2025 Annual Report on Form 10-K for the fiscal year ended December 28, 2025, filed with the SEC.\n\nOur digital technology risk and cybersecurity programs focus on key areas, including:\n\n \n\n \n \n\nGovernance\n \n\nSenior management aligns procedures and guidelines to the broader business strategy. Policies are reviewed and updated regularly. New policies are developed and launched as appropriate to address new and emerging risks.\n\n \n\nWe leverage third-party subject matter experts across several areas in a manner that aligns with leading industry recommendations.\n\n \n\nThe Company’s Chief Digital and Information Officer reports to the Audit and Risk Committee quarterly.\n\nSecurity Awareness / Training\n \n\nAll employees are asked to certify that they understand and adhere to our Code of Conduct, which emphasizes employee responsibility for information security and the protection of ATI digital systems and equipment from unauthorized use.\n\n \n\nWe provide annual cybersecurity training for all employees, as well as role-specific information security training.\n\n \n\nSecurity awareness communications are distributed regularly to address new and emerging risks and other topics of immediate concern.\n\n \n\nWe sponsor a “Cyber Security Month” in October each year and conduct regular phishing exercises.\n\nTechnical Safeguards\n \n\nWe deploy measures to protect our operational technology environments, on-premises and cloud computing environments, network perimeter, and internal digital technology platforms.\n\n \n\nProtection measures include:\n\n \n\n◆\n\ninternal and external firewalls;\n\n \n\n◆\n\nnetwork intrusion detection;\n\n \n\n◆\n\npenetration testing;\n\n \n\n◆\n\nvulnerability assessments;\n\n \n\n◆\n\nthreat intelligence; and\n\n \n\n◆\n\nanti-malware and access controls.\n\nIncident Response\nPlans\n \n\nWe maintain and update incident response plans that address the life cycle of a cyber incident. We routinely evaluate the effectiveness of such plans.\n\n \n\nIncident response plans focus on:\n\n \n\n◆\n\ntechnical issues, including detection, response and recovery;\n\n \n\n◆\n\nincident reporting and escalation;\n\n \n\n◆\n\nexternal communication and legal compliance; and\n\n \n\n◆\n\nbreach simulations and penetration testing through internal and external exercises.\n\nInsurance\n \nWe maintain a cybersecurity risk policy.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n26\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nOur Corporate Governance Our Board and its Role\n\n \n\nCorporate Responsibility Risk Oversight\n\n \n\n \n \n\nClimate Change/ Environmental Sustainability\n \nThe Audit and Risk Committee is broadly responsible for assisting the Board in overseeing risks associated with climate change and other environmental compliance and sustainability matters. The Committee regularly discusses with management the Company’s significant risk exposures and the steps management has taken to monitor and control such exposures, including our risk assessment and risk management guidelines and policies.\n\nTalent Development/ Social Responsibility\n \nThe Compensation and Leadership Development Committee assists the Board in its responsibility for oversight of executive compensation and management organization matters generally. It monitors and encourages the development of intellectual capital and oversees the Company’s talent development policies and procedures, including its workforce and professional development initiatives; the impact to the Company of current or anticipated political, legislative or regulatory trends or developments regarding human capital management; and management’s efforts to mitigate any resulting risks to the Company and its culture.\n\nGovernance\n \nThe Nominating and Governance Committee assists the Board in overseeing our corporate governance practices and profile, including, as appropriate, the legal standards, prevailing recommended practices, investor views, and potential benefits and risks associated with or impacting our governance practices and profile. It leads the Board’s director succession planning and recruitment efforts and makes recommendations to the Board concerning its committee structure, committee membership and committee leadership. The Nominating and Governance Committee also helps the Board establish and determine whether individual directors satisfy the pertinent qualifications for the Board’s various committees and to identify which responsibilities to delegate to its various committees.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nOur Corporate Governance Our Board and its Role\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n27 \n\n \n\nBoard Committees\n\nThe Board has three standing committees, its: Audit and Risk Committee; Nominating and Governance Committee; and Compensation and Leadership Development Committee. Each of these committees is composed entirely of independent directors.\n\nEach committee has a written charter that describes its responsibilities, and each has the authority to independently engage outside legal, accounting or other advisors or consultants. In addition, each committee annually conducts a review and evaluation of its performance and reviews and reassesses its charter.\n\n \n\n Director(1)\n\n \nAudit and Risk   \n \n\nNominating   \n\nand Governance   \n\n \n\nCompensation   \n\nand Leadership   \n\nDevelopment   \n\n \n\n \n \n \n\n L. M. Ball\n \n∎  \n \nCHAIR  \n \n\n \n\n \n\n \n \n \n\n H. J. Carlisle\n \n∎  \n \n\n \n\n \n∎  \n\n \n\n \n \n \n\n C. Corvi\n \n\n \n\n \n∎  \n \nCHAIR  \n\n \n\n \n \n \n\n J. B. Harvey\n \n\n \n\n \n∎  \n \n∎  \n\n \n\n \n \n \n\n D. P. Hess\n \n\n \n\n \n∎  \n \n∎  \n\n \n\n \n \n \n\n M. Kah\n \n∎  \n \n\n \n\n \n∎  \n\n \n\n \n \n \n\n E. Lund\n \n∎  \n \n\n \n\n \n\n \n\n \n\n \n \n \n\n J. Lydon-Rodgers\n \n∎  \n \n\n \n\n \n\n \n\n \n\n \n \n \n\n D. J. Morehouse\n \n\n \n\n \n∎  \n \n\n \n\n \n\n \n \n \n\n R. Sharma\n \nCHAIR  \n \n\n \n\n \n\n \n\n \n\n \n \n \n\n Number of Meetings held in 2025\n \n8  \n \n5  \n \n5  \n\n \n\n \n\n(1)\n\nMr. Wetherbee and Ms. Fields are not members of any of the Board’s standing committees. However, either may attend any committee meeting, except to the extent that a committee requests to meet without them.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n28\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nOur Corporate Governance Our Board and its Role\n\n \n\nAudit and Risk Committee\n\n \n\n \n\n \n\n Number of 2025 Meetings: 8\n\n \n\n \n\n  \n \n\n \n\nChair:\n\nRuby Sharma\n\n \n\nMembers:\n\nLeroy M. Ball, Jr.\n\nHerbert J. Carlisle\n\nMarianne Kah\n\nElizabeth H. Lund\n\nJean Lydon-Rodgers\n\n \n\nMr.Ball and Ms. Sharma each meet the SEC criteria for an “audit committee financial expert” and related NYSE requirements for accounting or related financial management expertise.\n\n \n\nRole and Primary Responsibilities:\n\nAssists the Board in its oversight of the integrity of the Company’s financial statements, compliance with legal and regulatory requirements, the qualifications, independence and performance of the Company’s independent auditors, and the performance of the Company’s internal audit function, as well as the Company’s major financial policies and actions, including with regard to the following items.\n\n \n\n◆\n\nRetention, compensation, evaluation and oversight of ATI’s independent auditors, including:\n\n \n\n–\n\npre-approval of engagement fees and all audit and non-audit services to be performed by the independent auditors;\n\n \n\n–\n\nreview and approval of the annual audit plan;\n\n \n\n–\n\noversight of auditor independence and internal quality and control procedures; and\n\n \n\n–\n\nperiodic review of the experience and qualifications of the independent auditors’ lead partner and evaluation of compliance with applicable partner rotation requirements.\n\n \n\n◆\n\nOversight of the Company’s internal audit function, including staffing levels and the annual internal audit plan.\n\n \n\n◆\n\nThe Company’s quarterly and annual financial statements and earnings releases and related SEC reports, including:\n\n \n\n–\n\ncritical accounting policies and practices, new accounting pronouncements and related disclosures;\n\n \n\n–\n\nsignificant financial reporting issues and judgments and the treatment of complex or unusual transactions;\n\n \n\n–\n\nsignificant internal control matters, including recommendations as to the adequacy of the Company’s system of internal controls; and\n\n \n\n–\n\ncritical audit matters and related disclosures.\n\n \n\n◆\n\nThe Company’s various compliance programs.\n\n \n\n◆\n\nGenerally, the identification, evaluation and mitigation, as appropriate, of significant risks to the Company and its business, operations and results, including without limitation risks associated with climate change and other environmental compliance and sustainability matters and cybersecurity risk.\n\n \n\n◆\n\nThe review and approval of any related party transaction.\n\n \n\n◆\n\nThe Company’s debt and equity structure, dividends, authorized capital stock, and credit agreements.\n\n \n\nBoth the independent auditors and the internal auditors have full access to and meet with the Committee on a routine basis without management being present. Additionally, the Audit and Risk Committee serves as named fiduciary of certain employee benefit plans maintained by the Company.\n\nNominating and Governance Committee\n\n \n\n \n\n Number of 2025 Meetings: 5\n\n \n\n \n\n  \n \n\n \n\nChair:\n\nLeroy M. Ball, Jr.\n\n \n\nMembers:\n\nCarolyn Corvi\n\nJ. Brett Harvey\n\nDavid P. Hess\n\nDavid J. Morehouse\n\n \n\nRole and Primary Responsibilities:\n\nAssists the Board in its oversight of the Company’s corporate governance matters, including through recommendations regarding:\n\n \n\n◆\n\nThe annual evaluation of the Board and its committees;\n\n \n\n◆\n\nThe Board’s director succession planning and recruitment efforts;\n\n \n\n◆\n\nThe Board’s committee structure, membership and leadership and appropriate delegations of authority to its various committees;\n\n \n\n◆\n\nOversight of sustainability matters through the operation of its committees;\n\n \n\n◆\n\nDirector nominees to the Board, including evaluation of new candidates and current directors who are being considered for re-election; and\n\n \n\n◆\n\nThe Company’s director compensation program.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nOur Corporate Governance Our Board and its Role\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n29 \n\n \n\nCompensation and Leadership Development Committee\n\n \n\n \n\n \n\n Number of 2025 Meetings: 5\n\n \n\n \n\n  \n \n\n \n\nChair:\n\nCarolyn Corvi\n\n \n\nMembers:\n\nHerbert J. Carlisle\n\nJ. Brett Harvey\n\nDavid P. Hess\n\nMarianne Kah\n\n \n\nEach member of the Compensation and Leadership Development Committee is a “non-employee director” of the Company as defined under Rule 16b-3 of the Securities Exchange Act of 1934 (the “Exchange Act”).\n\n \n\nRole and Primary Responsibilities:\n\nAssists the Board in its oversight of the Company’s executive compensation programs, including through recommendations regarding:\n\n \n\n◆\n\nCEO and other executive officer compensation, based on reviews, with outside compensation consultants and other advisors, of best practices, policies and practices at peer companies and other information and recommendations;\n\n \n\n◆\n\nGoals and objectives for CEO and other executive officer compensation, the CEO’s performance in light of those goals and objectives, and the CEO’s compensation level based on this evaluation;\n\n \n\n◆\n\nNon-CEO executive officer compensation;\n\n \n\n◆\n\nIncentive compensation plans and equity-based plans that require Board approval and administration of those plans;\n\n \n\n◆\n\nThe development of the Company’s talent and culture, including as they relate to succession planning and professional development, retention and recruitment of key talent, cultivation of workplace respect and culture, prevention of workplace violence, and encouragement of employee engagement and wellness; and\n\n \n\n◆\n\nCurrent or anticipated political, legislative or regulatory trends or developments regarding human capital management, their impact on the Company’s labor and employment policies and practices, and management’s efforts to mitigate any resulting risks to the Company.\n\n \n\nThe Compensation and Leadership Development Committee has the sole authority to retain, approve fees and other terms for, and terminate any compensation consultant used to assist the Committee in the evaluation of CEO or other executive compensation. The Committee also may obtain advice and assistance from internal or external legal, accounting or other advisors. Currently, the Committee has retained an independent compensation consultant, Meridian Compensation Partners, LLC, and utilizes external legal advisors.\n\n \n\nPlease see the “Executive Compensation — Compensation Discussion and Analysis” section of this Proxy Statement for more discussion about the Committee’s role in setting executive officer compensation.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n30\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nOur Corporate Governance Governance Policies and Practices\n\n \n\nGOVERNANCE POLICIES AND PRACTICES\n\nCorporate Governance Guidelines\n\nOur Board of Directors has adopted Corporate Governance Guidelines designed to assist the Board in the exercise of its duties and responsibilities to the Company. The Guidelines, which are available on our website atimaterials.com, at “Investors – Corporate Governance,” reflect the Board’s commitment to monitoring the effectiveness of decision making at the Board and management levels, with a view to achieving ATI’s strategic objectives. The Guidelines are subject to modification by the Board at any time.\n\nBoard Independence\n\nThe Board does not consider Mr. Wetherbee, our Executive Chairman, or Ms. Fields, our President and Chief Executive Officer, to be independent. At its February 2026 meeting, the Board determined that the remaining directors are independent in accordance with NYSE listing standards, our own Board independence standards and applicable SEC rules. Our own Board independence standards are included within our Corporate Governance Guidelines.\n\nBoard Self-Assessment\n\nAnnually, our Lead Independent Director facilitates the Board’s own self-assessment process, the results of which help to inform Board-level discussions regarding Board and committee composition, Board succession planning and potential director candidates, corporate governance practices and other matters.\n\n \n\nDirector Attendance at Meetings\n\nDuring 2025, our Board held six meetings, including a multi-day strategy meeting. In 2025, our current directors attended 96% of all Board meetings and meetings of Board committees of which they were members.\n\nOur independent, non-management directors meet separately in regularly scheduled executive sessions without members of management, except to the extent that the non-management directors request the attendance of a member of management. Our Lead Independent Director presides over such meetings. We generally schedule a Board meeting in conjunction with our Annual Meeting of Stockholders, and it is expected that our directors will attend the Annual Meeting absent good reason. In 2025, all directors attended our Annual Meeting.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nOur Corporate Governance Governance Policies and Practices\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n31 \n\n \n\nCode of Conduct\n\nOur Code of Conduct applies to all directors, officers and employees, including our principal executive officer, our principal financial officer and our principal accounting officer and controller. We require all directors, officers and employees to adhere to our Code of Conduct in addressing legal and ethical issues encountered in their work.\n\nOur Code of Conduct requires that our directors, officers and employees avoid conflicts of interest, comply with applicable laws, conduct business in an honest and ethical manner, and otherwise act with integrity and honesty in all of their actions by or on behalf of the Company. The Code includes provisions intended to promote honest and ethical conduct, full and accurate reporting, and compliance with laws, as well as other matters.\n\nOnly the Audit and Risk Committee of the Board can amend or grant waivers from the provisions of the Code of Conduct relating to the Company’s executive officers and directors, and any such amendments or waivers will be promptly posted on our website at ATImaterials.com. To date, no such amendments have been made or waivers granted.\n\nEmployee Training\n\nAll employees annually receive a copy of the Code of Conduct. Each year, we require all officers and managers to certify as to their understanding of and compliance with the Code of Conduct. In addition, all directors, officers and other employees are asked annually to complete an interactive online ethics course addressing the Code of Conduct. This online ethics training administered by a third party is part of ATI’s broader ethics and compliance program. In 2025, ATI’s online ethics and compliance courses addressed:\n\n \n\n◆\n \n\nATI’s Code of Conduct;\n\n \n\n◆\n \n\npreventing fraud, waste and abuse;\n\n \n\n◆\n \n\nconflicts of interest;\n\n \n\n◆\n \n\nprofessional behavior and workplace respect; and\n\n \n\n◆\n \n\nspeaking up and reporting concerns/ no retaliation.\n\nWe encourage employees to communicate concerns before they become problems. We believe that building and maintaining trust, respect and communication between employees and management and among employees is critical to the overarching goal of efficiently producing high quality products, providing the maximum level of customer satisfaction, and ultimately fueling profitability and growth.\n\nThe ATI Speak Up Line provides for confidential, secure, and anonymous reporting and is available 24 hours a day. Additionally, our Chief Compliance Officer and ethics officers at our operating companies also provide confidential methods for employees to surface their concerns without fear of reprisal.\n\nRelated Party Transactions\n\nThe Board has adopted a written Statement of Policy with respect to Related Party Transactions. The Policy applies to transactions or arrangements between ATI and a related person (namely directors, executive officers, and their immediate family members, and 5% stockholders) with a direct or indirect material interest in the transaction, including transactions requiring disclosure under Item 404(a) of Regulation S-K.\n\nUnder the Policy, no related party transaction may occur unless it is approved or ratified by the Audit and Risk Committee or approved by the disinterested members of the Board. The Audit and Risk Committee is primarily responsible for approving and ratifying related party transactions, and in doing so, will consider all matters it deems appropriate, including the dollar value of the proposed transaction, the relative benefits to be obtained and obligations to be incurred by the Company, and whether the terms of the transaction are comparable to those available to third parties. In 2025, ATI did not enter into any related party transactions that would require disclosure in this Proxy Statement.\n\nCompensation Committee Interlocks and Insider Participation\n\nNo member of the Compensation and Leadership Development Committee is an officer or employee of the Company. No member of the Committee has a current or prior relationship, and none of our executive officers have a relationship, to any other company that is required to be described under the SEC rules relating to disclosure of executive compensation.\n\nDelinquent Section 16(a) Reports\n\nSection 16(a) of the 1934 Act requires the Company’s directors and certain officers, as well as persons who beneficially own more than 10% of ATI’s outstanding shares of common stock, to file reports regarding their initial stock ownership and subsequent changes to their ownership with the SEC. Based solely on a review of the reports filed for fiscal year 2025 and related written representations, we believe that all Section 16(a) reports were filed on a timely basis, except for one Form 4 that, due to administrative error, was filed on March 21, 2025, for Michael B. Miller to report the withholding of shares in connection with an award vesting that occurred on March 3, 2025.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n32\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nOur Corporate Governance Investor Outreach and Stockholder Engagement\n\n \n\nINVESTOR OUTREACH AND STOCKHOLDER ENGAGEMENT\n\nWe value the input we receive from our stockholders. As part of our investor relations program, we engage in a structured communication program with certain investors, actively engaging with them throughout the year. We solicit their feedback on a variety of relevant matters, which may include corporate governance topics, our executive compensation program and sustainability initiatives, among other matters. Our goal is to be responsive to our stockholders and to appropriately understand and effectively address their concerns and observations.\n\nStockholder Engagement Cycle\n\n \n\n \n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nOur Corporate Governance Director Compensation\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n33 \n\n \n\nProcess for Communicating With Directors\n\n \n\n \n\n \n\nATI stockholders or interested parties who want to communicate with the Board, the Executive Chairman or Lead Independent Director, or any individual director can write to:\n\n \n\n \n\nExecutive Chairman/Lead Director\n\nc/o Corporate Secretary\n\nATI Inc.\n\n2021 McKinney Avenue\n\nDallas, TX 75201\n\n \n\nYour letter or message should indicate whether you are an ATI stockholder.\n\nDepending on the subject matter, the Executive Chairman or Lead Independent Director and/or Corporate Secretary will:\n\n \n\n◆\n \nforward the communication to the director or directors to whom it is addressed;\n\n \n\n◆\n \nattempt to handle the inquiry directly when, for example, it is a request for information about the Company or it is a stock-related matter; or\n\n \n\n◆\n \nnot forward the communication if it is primarily commercial in nature or it relates to an improper or irrelevant topic.\n\nAt each Board meeting, the Corporate Secretary presents a summary of all communications received since the last meeting that were not forwarded and makes those communications available to the directors on request.\n\n \n\n \n\n \n\nDIRECTOR COMPENSATION\n\nNon-employee directors receive competitive, market-based compensation for their service that is designed to fairly compensate them for their Board responsibilities and align their interests with those of our stockholders. The Nominating and Governance Committee periodically evaluates our non-employee director compensation program compared to industry peers and best practices and uses an independent consultant, Meridian Compensation Partners, LLC, to provide market and comparison data and information on current developments in director compensation.\n\nElements of Director Compensation\n\n \n\nPay Component\n  \n2025 Compensation\n\nAnnual Retainer\n  \n\n$250,000\n\n– $125,000 Cash\n\n– $125,000 Restricted Stock Value\n\n \n\nLead Independent Director Retainer\n\n \n\n  \n\n$40,000\n\n \n\nCommittee Chair Retainers\n\n \n\n \n\n  \n\nAudit and Risk $25,000\n\nCompensation and Leadership Development $20,000\n\nNominating and Governance $15,000\n\n \n\nBoard service travel expenses are also paid by the Company\n\n \n\nDirector Stock Ownership Guidelines\n\nThe Board encourages directors to obtain a meaningful stock ownership interest in ATI. Under our stock ownership guidelines, each non-employee director is expected to own, within five years of his or her initial election to the Board, ATI common stock having an aggregate value at least equal to four times the amount of the annual cash retainer that we pay to our directors. Furthermore, directors are required to retain one-third of any awarded stock until compliance with the guidelines is achieved. Our directors may opt to receive all or a portion of their cash retainer in shares of ATI stock. Each of our directors complied with the guidelines as of December 31, 2025, or is on track to comply by the five-year anniversary of their initial election to the Board.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n34\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nOur Corporate Governance Our Approach to Corporate Responsibility\n\n \n\n2025 Non-Employee Director Compensation\n\n \n\nName(1)\n  \nFees Earned Or\nPaid In Cash\n($)(2)\n \n  \nStock\nAwards\n($)(3)\n \n  \n\nAll Other\n\nCompensation\n\n  \nTotal\n($)\n \n\nL. M. Ball\n  \n \n150,000\n \n  \n \n124,953\n \n  \n–\n  \n \n274,953\n \n\nH. J. Carlisle\n  \n \n125,000\n \n  \n \n124,953\n \n  \n–\n  \n \n249,953\n \n\nC. Corvi\n  \n \n145,000\n \n  \n \n124,953\n \n  \n–\n  \n \n269,953\n \n\nJ. B. Harvey\n  \n \n0\n \n  \n \n304,945\n \n  \n–\n  \n \n304,945\n \n\nD. P. Hess\n  \n \n0\n \n  \n \n264,930\n \n  \n–\n  \n \n264,930\n \n\nM. Kah\n  \n \n125,000\n \n  \n \n124,953\n \n  \n–\n  \n \n249,953\n \n\nE. Lund(4)\n  \n \n20,720\n \n  \n \n20,790\n \n  \n–\n  \n \n41,060\n \n\nJ. Lydon-Rodgers(4)\n  \n \n20,720\n \n  \n \n20,790\n \n  \n–\n  \n \n41,060\n \n\nD. J. Morehouse\n  \n \n0\n \n  \n \n249,981\n \n  \n–\n  \n \n249,981\n \n\nR. Sharma\n  \n \n125,000\n \n  \n \n124,953\n \n  \n–\n  \n \n249,953\n \n\nNon-employee directors are not granted option awards or non-equity incentive plan awards, and do not have ATI pensions or non-qualified deferred compensation earnings.\n\n \n\n(1)\n\nMr. Wetherbee and Ms. Fields do not receive any compensation for their service on the Board.\n\n \n\n(2)\n\nThis column reflects annual retainer fees, including committee Chair fees. During 2025, our non-employee directors had the option to receive all or a specified portion of their annual retainer fees in restricted shares of our common stock. Messrs. Harvey, Hess and Morehouse each elected to receive ATI stock in lieu of the portion of the 2025 director compensation that they would otherwise have been paid in cash.\n\n \n\n(3)\n\nThis column reflects the aggregate grant date fair value, determined in accordance with FASB ASC Topic 718, of the restricted stock awards granted to directors under the Company’s Non-Employee Director Restricted Stock Program. Shares granted in 2025 vest on the first anniversary of the date of grant, or earlier upon retirement, death or change of control, and expense is recognized over the vesting period. The fair value of nonvested stock awards is measured based on the average of the high and low trading prices for a share of the Company’s stock price on the date of grant.\n\n \n\n(4)\n\nRepresents a pro-rated award for each of Ms. Lund and Ms. Lydon-Rodgers, who both were appointed to the Board as of November 1, 2025.\n\nOUR APPROACH TO CORPORATE RESPONSIBILITY\n\nOur Core Values\n\nAt ATI, we recognize that long-term excellence and profitability require that we operate in ways that promote environmental and social sustainability, supported by appropriate governance structures and enterprise risk oversight practices. At the center of our commitment to excellence are our core values, which drive how we succeed:\n\n \n\nAligned with these core values, we are committed to ensuring the quality, diversity and sustainability of our workforce, enhancing the communities we impact, and protecting our people and our planet through our products and the way we operate. Under our short-term incentive program, the Compensation and Leadership Development Committee of our Board has expressly reserved the broad discretion to reduce or eliminate any annual\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nOur Corporate Governance Our Approach to Corporate Responsibility\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n35 \n\n \n\ncash incentive award that may otherwise be payable to one or more participants, including our NEOs, if the Committee believes any facet of our financial or operational performance, especially in relation to workplace safety, the environmental impact of our business, or any other aspect of our annual performance with the potential to impact the sustainability of our business is substandard.\n\nEnvironmental Stewardship\n\nAll ATI operations are committed to:\n\n \n\n◆\n \n\nReducing their energy intensity through conservation efforts and energy efficiency;\n\n \n\n◆\n \n\nReducing greenhouse gas emissions through operational efforts, energy conservation and procurement strategies;\n\n \n\n◆\n \n\nReducing water withdrawal through conservation, reuse, and equipment modification; and\n\n \n\n◆\n \n\nIncreasing the amount of recycled materials we use to eliminate waste in all phases of our manufacturing processes. Approximately 81% of the raw materials that ATI used in 2024 to manufacture specialty metals started from recycled materials.\n\nSolving the World’s Climate Challenges\n\n \n\n \n\nATI’s innovative and exacting products and processes are helping to solve the world’s climate challenges by supporting the transition to a lower-carbon economy. Customers rely on ATI for materials with enhanced corrosion and/or heat resistance, strength and other properties for a wide array of applications that promote greenhouse gas reduction and environmental sustainability, including alloys and components that:\n\n \n\nGoals for Reducing Our Environmental Impact\n\n \n\n \n\nWe established the following 2030 goals related to reductions in GHG emissions and water intake, as well as targets for increases in our already extensive use of recycled materials, in each case compared to our 2018 baseline.\n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n36\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nOur Corporate Governance Our Approach to Corporate Responsibility\n\n \n\nTalent and Culture\n\nWe believe that our people and culture are competitive differentiators. Our long tradition of innovation and operational excellence demands the contributions of leaders and team members with a wide array of characteristics, experience, knowledge and skills. We attract, develop and retain purpose and performance-driven leaders to build teams with diverse views and empowered and fulfilled employees who want to stay and grow with the Company.\n\nAttract\n\n \n\n \n\n \n\n◆\n \n\nWe believe in providing a welcoming, engaging and inclusive assessment and interviewing process that encourages people from all backgrounds to consider ATI.\n\n \n\n◆\n \n\nWe partner with top academic institutions that have programs relevant to our business, external professional organizations, trade schools and high schools to enhance our workforce and identify materials science, STEM and other relevant expertise.\n\n \n\n◆\n \n\nOur #ProvenPerformers brand campaign focuses on storytelling by a wide array of employees, tying innovative solutions and technologies back to our talent and their work at ATI.\n\nDevelop\n\n \n\n \n\n \n\n◆\n \n\nDeveloping leaders and talent at all levels of the organization is critical to our long-term success. We have early career, technical, leadership and management development programs, as well as skill building in manufacturing and frontline leader development to support career growth.\n\n \n\n◆\n \n\nFocused individual development and succession planning for critical roles helps us develop talent and build strong feeder pipelines.\n\nEngage\n\n \n\n \n\n \n\n◆\n \n\nWe continuously strive to cultivate and support a highly engaged and productive workforce. We actively seek opportunities for our employees to interact and share their perspectives with our CEO and other senior executive leaders.\n\n \n\n◆\n \n\nWe conduct confidential company-wide engagement surveys that offer our employees the ability to provide feedback.\n\n \n\n◆\n \n\nEmployee Resource Groups (“ERGs”) foster professional development, social connectivity, and community involvement, and celebrate diversity throughout our company. Currently, we have two ERGs, the AWN (ATI Women’s Network), with five chapters and enterprise business executive sponsorship and our employee-led IDEA (Inclusion, Diversity, Equity and Accessibility) Council.\n\nRetain\n\n \n\n \n\n \n\n◆\n \n\nOur pay for performance philosophy is reflected in our annual employee performance assessment process. We believe ongoing feedback is necessary to maintain our high-performance culture, and managers regularly meet with employees to support development and performance improvement. Managers review the annual assessment results, including performance ratings and associated short-term incentive compensation outcomes, with employees.\n\n \n\n◆\n \n\nWe maintain a formal succession planning process that works in connection with performance management for systematic career development at both the individual employee and enterprise levels. We believe that the robust and systematic nature of these programs is critical to optimizing our talent management and providing for sustainably high-quality leadership of our business over the long term.\n\nCorporate Responsibility Reporting\n\nATI published its most recent Corporate Responsibility Report in April 2025, addressing our environmental sustainability, social responsibility and corporate governance efforts during 2024 consistent with the Sustainability Accounting Standards Board (“SASB”) framework. The report provides an overview of environmental, workforce health, and safety and community sustainability efforts and achievements across our business. We also report on specific environmental sustainability goals that ATI will pursue through 2030. We intend to publish our report and update our stakeholders on our progress toward these goals annually. We anticipate publishing an updated Corporate Responsibility Report addressing these matters prior to our 2026 Annual Meeting.\n\nAdditionally, we report on the impact of climate change on our business, consistent with the Taskforce on Climate-related Financial Disclosures (“TCFD”) framework. Our most recent Reports are available at ATImaterials.com/aboutati/Pages/safety-sustainability.aspx.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nATI’s Executive Management  \n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n37 \n\n \n\nATI’s Executive Management\n\nAs of March 24, 2026, our executive officers include:\n\n \n\nName\n  \nBiographical information\n\nRobert S. Wetherbee, 66\nExecutive Chairman\nsince July 2024\n\n \n\n \n\n  \nMr. Wetherbee became Executive Chairman in July 2024, after serving as ATI’s Chief Executive Officer from January 2019 to July 2024. He has been a member of the Board since January 2019 and was appointed Board Chair in May 2021. Additionally, he served as President from January 2019 until June 2023. Previously, Mr. Wetherbee was Executive Vice President, ATI Flat Rolled Products Group, from January 2015 to December 2018, and prior to that, was the President of ATI Flat Rolled Products from April 2014 to January 2015. Mr. Wetherbee joined ATI in 2010 following a 29-year career with Alcoa Inc. and served as President of ATI’s tungsten business from 2010 through 2012. From March 2013 to February 2014, Mr. Wetherbee was President and Chief Executive Officer of Minerals Technologies, Inc. Currently, Mr. Wetherbee also serves on the board of directors of Commercial Metals Company, which offers products and technologies to meet the critical reinforcement needs of the global construction sector, and GATX Corporation, which leases transportation assets and provides related services to customers worldwide.\n\nKimberly A. Fields, 56\n\nDirector; President and CEO\nsince July 2024\n\nBoard Chair-Elect\n\n \n\n \n\n  \nMs. Fields became ATI’s President and Chief Executive Officer on July 1, 2024 and has been appointed Board Chair effective at the conclusion of the Annual Meeting. She became President and Chief Operating Officer in June 2023, having served as Executive Vice President and Chief Operating Officer from January 2022 to June 2023, as Executive Vice President, AA&S and HPMC throughout 2021, and as Executive Vice President, Advanced Alloys & Solutions from April 2019 to December 2020. She joined ATI in April 2019 after serving as Group President at IDEX Corporation since 2015. Previously, Ms. Fields served as Executive Vice President for the integrated global steel producer EVRAZ, where she had full responsibility for all activities for the $2 billion North American Flat Products business. Prior to that, Ms. Fields was General Manager of Industrials for GE Energy, with global responsibility for growing GE’s penetration in metals, petrochemicals and mining segments, after holding a series of leadership positions with Alcoa, Inc., The Boston Consulting Group and Owens Corning Fiberglass. Ms. Fields also served on the board of directors of Silgan Holdings Inc. from July 2019 to July 2024.\n\nJames R. Foster, 45\n\nSenior Vice President,\nFinance and Chief Financial\nOfficer since January 2026\n\n \n\n  \nMr. Foster became Senior Vice President, Finance and Chief Financial Officer on January 1, 2026, after serving as Vice President, ATI Financial and Operating Strategies since July 2025 and as a President of the Company’s Specialty Alloys & Components business unit from August 2023 to July 2025. He was Vice President, Finance overseeing the finance function for both of ATI’s segments from December 2019 to August 2023, following a series of other leadership roles at ATI from 2012 to 2019. Mr. Foster previously held senior finance roles at API Technologies Corp. and Spectrum Control Inc. and worked at Ernst & Young.\n\nVaishali S. Bhatia, 43\n\nSenior Vice President, General\nCounsel and Chief Compliance\nOfficer since March 2024\n\n \n\n \n\n  \nMs. Bhatia joined ATI in her current role after serving as Executive Vice President, General Counsel and Secretary of HF Sinclair Corporation, an independent energy company that produces and markets high-value light products such as gasoline, diesel fuel, jet fuel, renewable diesel and other specialty products, since March 2023. Previously, she served in a series of senior roles with HF Sinclair and its predecessor company, HollyFrontier, since 2011, including Senior Vice President, General Counsel and Secretary from November 2019 to March 2023, Acting General Counsel and Secretary from August 2019 to November 2019 and Assistant General Counsel and Assistant Secretary from May 2017 to August 2019. Prior to joining HF Sinclair, Ms. Bhatia was an associate at Jones Day, a global law firm.\n\nTimothy J. Harris, 51\n\nSenior Vice President,\nChief Digital and Information\nOfficer since May 2019\n\n \n\n \n\n  \nMr. Harris joined ATI as Senior Vice President, Chief Digital and Information Officer after serving as Chief Information Officer at Andeavor from November 2016 to April 2019. Prior to that, he held a series of senior positions at Mylan N.V., including most recently Chief Technology Officer and head of Global Technology Services from June 2013 to March 2016. Before joining Mylan, Mr. Harris held several global technology roles for Aviva PLC, following over ten years in leadership positions at Rockwell Collins.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n38\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nProposal 2: Advisory Vote to Approve Compensation of the Company’s Named Executive Officers\n\n \n\nProposal 2: Advisory Vote to Approve Compensation of the Company’s Named Executive Officers\n\nPursuant to Section 14A of the Exchange Act, each year we ask our stockholders to approve the compensation of ATI’s named executive officers. This proposal, commonly known as a “Say on Pay” proposal, gives our stockholders the opportunity to express their views on our NEOs’ compensation. This vote is not intended to address any specific item of compensation, but rather the overall compensation of our NEOs and the philosophy, policies and practices described in this Proxy Statement.\n\nWhile this vote is advisory, and not binding on our Company, it provides valuable information to our Compensation and Leadership Development Committee regarding investor sentiment about our executive compensation philosophy, policies and practices. The Committee will consider the outcome of this vote when determining executive compensation for the remainder of 2026 and in future years.\n\nWE USE EXECUTIVE COMPENSATION TO CREATE LONG-TERM STOCKHOLDER VALUE\n\nThe Committee periodically reviews our executive compensation program, considering whether it achieves the desired goal of offering total compensation consisting of base salary that is competitive with an identified peer group of companies and incentive opportunities that are performance-oriented and linked to the interests of stockholders. When casting your Say on Pay vote, we urge you to read the Compensation Discussion and Analysis section to learn more about our executive compensation program and to consider the following highlights:\n\nWe link compensation to ATI performance\n\n \n\n◆\n \n\nApproximately 91% of our CEO’s 2025 compensation opportunity was tied to performance and, therefore, “at risk.” Performance drives pay.\n\n \n\n◆\n \n\nOur short-term cash incentive and long-term equity incentive plans are based on the achievement of business plan performance targets, such as targets for operating profit, EBITDA, free cash flow, strategic goals, and relative total stockholder return.\n\n \n\n◆\n \n\nPayments with regard to the Company performance-vested components of both our annual and long-term incentive programs are made only when at least threshold performance targets are achieved.\n\nWe align compensation with stockholder interests\n\n \n\n◆\n \n\nAll of the long-term incentive compensation opportunities for our NEOs are equity-based.\n\n \n\n◆\n \n\nWe believe the metrics that drive our performance-vested compensation programs correlate with the achievement of sustained profitable growth in our business and reflect our commitment to growing shareholder value.\n\n \n\n◆\n \n\nOur stock ownership guidelines for senior executives denote ownership as a multiple of base salary, prescribing 6X ownership for our CEO, and require each of our executive officers retain at least 50% of the equity they are awarded until ownership guidelines are met.\n\nOUR MOST RECENT SAY ON PAY RESULTS\n\nATI consistently demonstrates its firm commitment to pay for performance, and in recent years, our executive compensation programs generally have garnered strong stockholder support. In each of 2023, 2024 and 2025, our Say on Pay proposal received the support of more than 98% of the shares voted at our Annual Meeting.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nProposal 2: Advisory Vote to Approve Compensation of the Company’s Named Executive Officers \n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n39 \n\n \n\nADVISORY VOTE ON EXECUTIVE COMPENSATION\n\nBefore voting, we encourage you to read the “Compensation Discussion and Analysis” section to learn more about our executive compensation program. We ask our stockholders to vote “FOR” the following resolution at the Annual Meeting:\n\n“RESOLVED, that the stockholders of ATI Inc. approve, on an advisory basis, the compensation of the named executive officers, as disclosed in the Company’s Proxy Statement for the 2026 Annual Meeting of Stockholders, pursuant to the compensation disclosure rules of the Securities and Exchange Commission, including the compensation discussion and analysis, the compensation tables and any related material disclosed in the Company’s Proxy Statement for the 2026 Annual Meeting of Stockholders.”\n\nBased on the recommendation of our stockholders at our 2023 Annual Meeting of Stockholders, and the Board’s consideration of that recommendation, we hold an advisory vote to approve the compensation of the Company’s named executive officers annually.\n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n40\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nCompensation Discussion and Analysis\n\n \n\nExecutive Compensation\n\nCOMPENSATION DISCUSSION AND ANALYSIS\n\n \n\nThis section discusses our executive compensation program and plans for our Named Executive Officers, or “NEOs”:\n\nKimberly A. Fields\n\nPresident and Chief Executive Officer\n\nDonald P. Newman\n\nRetired Executive Vice President, Finance and Chief Financial Officer\n\nVaishali S. Bhatia\n\nSenior Vice President, General Counsel and Chief Compliance Officer\n\nTimothy J. Harris\n\nSenior Vice President and Chief Digital and Information Officer\n\nRobert S. Wetherbee\n\nExecutive Chairman\n\n \n\n \n\n \n\n \n\n TABLE OF CONTENTS\n\n \n\n \n\n \n \n\n \n\n[1. Our Compensation Framework and Philosophy](#txa932857_101)\n  \n \n41\n \n\n[2. How We Determine Executive Compensation](#txa932857_102)\n  \n \n44\n \n\n[Compensation Setting Process](#txa932857_103)\n  \n \n44\n \n\n[Monitoring Performance and Progress](#txa932857_104)\n  \n \n45\n \n\n[Benchmarking Peer Group](#txa932857_105)\n  \n \n45\n \n\n[3. 2025 Executive Compensation Program Overview](#txa932857_106)\n  \n \n47\n \n\n[4. Details of 2025 Executive Compensation Program](#txa932857_107)\n  \n \n49\n \n\n[Base Salary](#txa932857_108)\n  \n \n49\n \n\n[Short-Term Incentive Program](#txa932857_109)\n  \n \n49\n \n\n[Long-Term Incentive Plan](#txa932857_110)\n  \n \n51\n \n\n[5. 2025 Business and Incentive Compensation Results](#txa932857_111)\n  \n \n54\n \n\n[6. Other Compensation Practices and Policies](#txa932857_112)\n  \n \n59\n \n\n[Compensation Committee Report](#txa932857_113)\n  \n \n60\n \n\n[2025 Compensation Tables](#txa932857_114)\n  \n \n \n \n\n[Summary Compensation Table](#txa932857_115)\n  \n \n61\n \n\n[Grants of Plan-Based Awards](#txa932857_116)\n  \n \n63\n \n\n[Outstanding Equity Awards at Fiscal Year-End](#txa932857_117)\n  \n \n64\n \n\n[Option Exercises and Stock Vested](#txa932857_118)\n  \n \n65\n \n\n[Pension Benefits](#txa932857_119)\n  \n \n65\n \n\n[Non-Qualified Deferred Compensation](#txa932857_120)\n  \n \n66\n \n\n[Employment and Change in Control Agreements](#txa932857_121)\n  \n \n67\n \n\n[Potential Payments Upon Termination](#txa932857_122)\n  \n \n69\n \n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nCompensation Discussion and Analysis 1. Our Compensation Framework and Philosophy\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n41 \n\n \n\n1.\n \nOUR COMPENSATION FRAMEWORK AND PHILOSOPHY\n\nOur Compensation Philosophy\n\nThe Compensation and Leadership Development Committee’s approach to compensation is to offer a base salary that is competitive with an identified benchmarking peer group of companies and incentive opportunities that are performance-oriented and linked to the interests of stockholders. The Committee has developed a balance of annual and long-term programs using diverse criteria to provide incentives while discouraging inappropriate risk taking. For the NEOs, the program consists of base salary, an annual performance-based cash incentive, longer-term performance-based equity compensation opportunities, and a time-based equity component that is intended to support retention.\n\nThe Committee views the executive compensation program as a management tool that, through a detailed and quantitative target-setting process, establishes challenging financial performance goals that encourage the management team to achieve or surpass ATI’s business objectives.\n\nThe Committee has determined that the executive compensation program should:\n\n \n\n◆\n \n\npay competitively by setting overall target compensation, which can be realized when performance targets are met, in line with target compensation at peer companies and other companies and industries with which ATI competes for executive talent;\n\n \n\n◆\n \n\nretain executives who are essential to driving ATI’s strategies and future growth;\n\n \n\n◆\n \n\nsupport ATI’s business strategy by tying incentive compensation to achievement of specific performance goals and strategic objectives; and\n\n \n\n◆\n \n\nalign with stockholder interests by putting substantial portions of compensation at risk through performance-oriented incentive pay opportunities.\n\nCompetitive Compensation\n\nThe Committee reviews, with outside compensation consultants and other advisors, the compensation policies and practices at peer companies that are in our industry and serving our end markets or with which ATI competes for talent. We use this information to help establish base compensation levels throughout the management organization within ranges around the approximate median of these groups. The variable components of our incentive awards provide opportunities to earn additional amounts if performance goals are met or exceeded, but do not pay out if performance goals are not met.\n\nAttract and Retain Talent\n\nWe designed our compensation program to attract and retain a deep pool of managerial talent, the members of which share ATI’s commitment to enhancing stockholder value in the short and longer terms. The Committee believes that the plans and performance goals included in our program will attract, challenge, and retain superior managers experienced in ATI’s businesses and direct their efforts toward specific achievements that the Board and senior management determine to be necessary for profitable growth through business cycles.\n\nSupport Achievement of Our Business Strategy\n\nThe Company uses performance measurement periods of three or more years for incentive programs other than our annual cash incentive plan to drive consistently strong performance over a longer period of time and to mitigate compensation risk. In this way, our programs both reward actual performance and are effective in driving achievement of the Company’s underlying near and longer-term goals.\n\nPay for Performance: Linking Executive Compensation to the Interests of Stockholders\n\nATI’s compensation framework emphasizes long-term value creation over short-term volatility. Performance metrics include EBITDA, free cash flow, and relative total shareholder return. Each metric was selected for its direct connection to sustainable earnings growth, capital efficiency, and stockholder returns. The Committee retains negative discretion to reduce awards if performance in areas such as safety, environmental stewardship, compliance, or risk management does not meet expectations. We believe this balanced structure supports strong governance and responsible compensation practices.\n\nIn 2025, performance goals focused on EBITDA, free cash flow and TSR, as well as individual strategic goals. The Committee considered the results of our most recent Say on Pay proposal, which was approved by more than 98% of the shares voted at our 2025 Annual Meeting, in designing the current executive compensation program.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n42\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nCompensation Discussion and Analysis 1. Our Compensation Framework and Philosophy\n\n \n\nWe believe that our compensation program is transparent and easy to understand, performance-driven and appropriately aligned with stockholders’ interests. Our program:\n\n \n\n \n\n \n\n \n\nPLACES SIGNIFICANT EMPHASIS ON FINANCIAL RESULTS\n\n \n\n \n\n \n\nALIGNS WITH OUR BUSINESS STRATEGIES AND PERFORMANCE\n\n \n\n \n\n \n\nREFLECTS COMPETITIVE MARKET DATA AND\nPRACTICES\n\n \n\n◆  Executive officer short-term cash incentive awards are 90% contingent on ATI’s financial performance.\n\n \n\n◆  For 2025, 70% of each executive officer’s regular annual equity award is contingent on our relative total shareholder return\n\n \n\n \n\n \n\n◆  Long-term equity incentive awards incorporate 3-year and 4-year equity performance-based incentives that align with our strategies.\n\n \n\n◆  Executive officer equity awards are heavily weighted in favor of performance stock units.\n\n \n\n \n\n \n\n \n\n◆  Executive officer compensation levels are benchmarked and reviewed annually\n\n \n\n◆  Equity incentive awards use double-trigger change in control vesting\n\n \n\n◆  We maintain robust stock ownership guidelines.\n\nRole of the Compensation and Leadership Development Committee\n\nThe Committee’s primary responsibility is to design compensation plans that support the Board’s and management’s long-term strategic vision for ATI and stockholder value creation over the long term. Over the last several years, the Committee has emphasized design clarity and transparency to better communicate with our stockholders and to align our compensation programs with evolving best practices.\n\nThe Committee is composed of five independent, non-employee directors. The Committee has the sole responsibility to carry out ATI’s overarching policy of linking our executive compensation program to the interests of our stockholders. To that end, the Committee is responsible for determining compensation for the NEOs and other executive officers and has the responsibility for oversight of the Company’s equity plans, variable compensation plans for executive officers and management’s implementation of those plans.\n\nRole of Independent Compensation Consultants\n\nThe Committee, under its charter, has the sole authority to retain and terminate any compensation consultant used in the evaluation of executive compensation and has the sole authority to approve the retention terms of the consultant, including fees. The compensation consultant retained by the Committee is responsible only to the Committee. The Committee reviews the consultant’s qualifications, including independence. The Committee may, at any time, contact the consultant without involving management.\n\nFor 2025, the Committee retained Meridian Compensation Partners, LLC, a nationally-recognized executive compensation consultant, for benchmarking compensation and program design and to provide advice on a variety of compensation related matters, including director compensation in cooperation with the Nominating and Governance Committee. Meridian, which the Committee determined is independent, provides no other services to ATI. Further, because Meridian is involved only in the business of executive compensation consulting, Meridian does not attempt to sell other services to the Company.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nCompensation Discussion and Analysis 1. Our Compensation Framework and Philosophy\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n43 \n\n \n\nExecutive Compensation Highlights\n\n \n\n \n\n WHAT WE DO\n\n \n\n \n\n \n\n \n\n \n\n \n\nCompensation linked to ATI performance.\n\nPerformance drives pay. A significant portion of our NEOs’ compensation opportunity is variable, meaning it is tied to performance. Payouts under cash and equity incentive plans are based on the attainment of performance metrics and are made only when at least threshold performance targets are achieved.\n\n \n\n \n\n \n\nBalanced compensation program.\n\nThe compensation program includes complementary but diverse performance goals, a balance of types of compensation, and caps on the amount of compensation that can be awarded.\n\n \n\n \n\n \n\nCompensation aligned with stockholder interests.\n\nLong-term incentive compensation opportunities for our NEOs are equity-based and tied to total shareholder return.\n\n \n\n \n\n \n\nDouble trigger change in control.\n\nATI’s equity incentive plan includes double trigger change in control provisions that apply to equity awards under the plan.\n\n \n\n \n\n \n\nIndependent compensation consultant.\n\nOur Compensation and Leadership Development Committee works closely with an independent compensation consultant.\n\n \n\n \n\nClawback policy.\n\nWe maintain robust executive compensation recovery arrangements that require the return of compensation under appropriate circumstances. These arrangements include, among others, our Executive Compensation Recovery Policy, which complies with SEC and NYSE rules, as well as additional recovery provisions that provide broader clawback discretion under certain circumstances.\n\n \n\n \n\n \n\nRobust stock ownership guidelines for directors and executive management.\n\nOur stock ownership guidelines for management include 6X base salary ownership for the CEO and require NEOs to retain 50% of the equity awarded to them until they meet the ownership guidelines.\n\n \n\n \n\n \n\nLimits on severance arrangements.\n\nSeverance arrangements are limited to 2.99X base salary.\n\n \n\n \n\n \n\nBoard compensation risk oversight.\n\nOur board regularly reviews various risks associated with our compensation program, which includes review of an annual risk analysis performed by our independent compensation consultant.\n\n \n\n \n\n \n\n \n\n WHAT WE DON’T DO\n\n \n\n \n\n \n\n \n\n \n\n \n\nNo employment agreements for executive officers.\n\n \n\n \n\n \n\nNo excise tax gross-ups in change in control agreements.\n\n \n\n \n\n \n\nNo executive perquisites such as significant unreimbursed personal air travel, club dues or tax gross-ups.\n\n \n\n \n\n \n\nNo hedging transactions or pledging of ATI stock by officers and directors.\n\n \n\n \n\n \nNo previously-granted awards can be repriced or surrendered in exchange for new awards.\n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n44\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nCompensation Discussion and Analysis 2. How We Determine Executive Compensation\n\n \n\n2.\n \nHOW WE DETERMINE EXECUTIVE COMPENSATION\n\nCompensation Setting Process\n\nThe Committee maintains a multi-step process for setting compensation levels and opportunities and validating our pay targets. The table below, and description that follows, explains this process.\n\n \n\n \n \n \n  \nResponsibility:\n  \nPurpose:\n  \nUsed to:\n\n \nReview of Annual and Long-Term Business Plans\n  \nBoard and management\n  \nAlign incentive compensation with business objectives\n  \nSupport determination of performance targets in incentive plans\n\n \n\n \n\nIndividual Performance Assessments\n\n  \n\n \n\nCLDC and CEO\n\n  \n\n \n\nEvaluate individual performance of CEO and, based on CEO input, our other executive officers\n\n  \n\n \n\n◆\n\nDetermine each executive officer’s personal performance relative to the individual goals that comprise the 10% component of his or her short-term incentive award and payments for the award period that recently ended\n\n \n\n◆\n\nAssist in setting individual award opportunities for the next year/ award cycle\n\n \nCompany Achievement of Performance Goals\n  \nCLDC and management\n  \nDetermine award payments based on Company performance in completed performance periods\n  \n\n◆\n\nDetermine award payouts\n\n \n\n◆\n\nAssist in determining appropriate performance goals for upcoming periods\n\n \nMarket and Peer Analysis\n  \nCompensation consultants\n  \nBenchmark and make compensation recommendations for our executives\n  \nSet competitive base pay and short-term and long-term incentive targets and compensation opportunities for the next year/ award cycle\n\n \nPay and Performance Analysis\n  \nCLDC and management\n  \nEvaluate pay and performance relative to publicly available financial and compensation information to validate individual compensation plans\n  \nAssess achievement under the incentive plans relative to Company and peer performance\n\n \n\n \n\nStockholder Outreach\n\n  \n\n \n\nManagement\n\n  \n\n \n\nUnderstand expectations of investors and monitor trends in executive compensation from the perspective of stockholders.\n\n  \n\n \n\nEvaluate compensation policies, practices and plans.\n\n \n\nNear the end of each year, the Board (including members of the Committee) reviews ATI’s annual and long-term business and strategic plans with management. The Committee reviews the Company’s year-end financial results and, based on its assessment of ATI’s achievement of the predefined financial goals and objectives, determines the extent to which awards with performance measurement periods that concluded at the end of the previous year are payable. The Committee authorizes compensation programs for the year and establishes specific financial performance goals for the performance period or periods applicable to awards under such programs in light of the Board-approved business and strategic plans.\n\nThe Committee considers which incentive plans, award levels and performance goals would optimize the achievement of ATI’s future business objectives without introducing systemic risk driven by the executive compensation program. The Committee solicits the views of its advisors as to whether the plans under consideration reflect and support achievement of the Company’s short-term and long-term business objectives and strategies. The Committee also approves individual participation levels in the compensation plans for the CEO and, with input from the CEO, our other executive officers and delegates to the CEO the authority to establish participation levels in the plans for other eligible employees within guidelines the Committee prescribes. Generally, prospective compensation opportunities under the long-term compensation plans are awarded during the first quarter.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nCompensation Discussion and Analysis 2. How We Determine Executive Compensation\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n45 \n\n \n\nMonitoring Performance and Progress\n\nThe Committee meets regularly during the year to monitor the Company’s performance, as well as the individual performance of our CEO and other executive officers, relative to the incentive plan goals. At these meetings, management provides the Committee with current financial data and with internal status reports on key performance measures. The Committee uses this information to:\n\n \n\n◆\n \n\nassess management’s interim progress toward achieving the predetermined performance goals and the potential payouts under the various executive compensation plans; and\n\n \n\n◆\n \n\nassist in the evaluation of whether the compensation plans continue to support and direct performance as required to achieve the Company’s business goals.\n\nMembers of management attend portions of these meetings. The Committee also meets with its outside compensation consultant and other advisors during non-management executive sessions to seek independent feedback on compensation-related matters.\n\nBenchmarking Peer Group\n\nThe Committee considers, with information provided by the compensation consultant, compensation practices across a peer group that the Committee uses as a reference in developing ATI’s executive compensation program and in determining the competitiveness of our executive compensation levels. The Committee also uses information regarding compensation practices across a broader survey of manufacturing companies as a check against the peer group information. Annually, the Committee reviews the composition of the peer group to confirm that the constituent companies remain relevant and provide meaningful comparisons for compensation and business purposes. ATI believes that there are no other public companies that engage in the full range of the Company’s specialty materials and components manufacturing and other related business. Therefore, the Committee’s independent compensation consultant developed the following criteria to guide the selection of peer companies for benchmarking compensation:\n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n46\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nCompensation Discussion and Analysis 2. How We Determine Executive Compensation\n\n \n\n2025 Benchmarking Peer Group\n\n \n\nFor 2025, the Committee retained the same peer group that was updated for 2024 to reflect the Company’s business transformation and leadership in aerospace and defense. For performance measurement periods under the executive compensation plans beginning on January 1, 2025, ATI performed against its peer group as follows:\n\n \n\nSource: Standard & Poor’s Capital IQ Database (Compustat financials)\n\nData represents each company’s fiscal year, which may not align with ATI’s fiscal year-end\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nCompensation Discussion and Analysis 3. 2025 Executive Compensation Program Overview\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n47 \n\n \n\n3.\n  \n2025 EXECUTIVE COMPENSATION PROGRAM OVERVIEW\n\nRegular Annual Executive Compensation Program\n\nOur regular executive compensation program for 2025 consists of the following elements for our NEOs:\n\n \n\n  \n  \nPlan\n  \nPurpose\n  \n\nRelevant Performance\n\nMetric and Description\n\n \n  \n\n ANNUAL/SHORT- \n\n TERM INCENTIVE \n\n  \nBase Salary\n  \nTo provide fair and competitive compensation for individual performance and level of responsibility of position held.\n  \nIndividual performance\n \n\n \n\nFIXED\n\n  \n2025 Annual Performance Plan\n  \nTo provide performance-based annual cash awards to motivate and reward key employees for achieving our short-term business objectives and to drive performance.\n  \n\nMix of metrics, including:\n\n \n\n◆\n\nEBITDA (60%)\n\n \n\n◆\n\nFree Cash Flow (30%)\n\n \n\n◆\n\nStrategic/Individual goals (10%)\n\n \n\n \n\n VARIABLE \n\nLONG- TERM INCENTIVE\n  \nLong-Term Incentive Plan: Performance Stock Units (“PSUs”) (70%)\n  \nTo provide performance-based equity compensation designed to drive ATI’s earnings and motivate key managers.\n  \n\nAwards vest at the end of a three-year performance period based on achievement of specified goals. Awards granted in 2025 vest based on the Company’s TSR relative to that of a predetermined peer group.\n\n  \nLong-Term Incentive Plan: Restricted Stock Units (“RSUs”) (30%)\n  \nTo enhance the program’s ability to retain participants and align executives’ and stockholders’ interests in share price appreciation.\n  \n\nTime-vested awards generally vest in equal annual installments on the first three anniversaries of the applicable grant date, subject to the award recipient’s continued employment by the Company.\n\nThe pie charts below show the mix of NEO compensation by type, form and length, at target for 2025 under our regular, annual compensation program, excluding the impact of our highly performance-contingent Enterprise Value Acceleration program, which is discussed on the following page.\n\n2025 Target Pay Mix\n\n \n\n \n\n \n\n    \n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n48\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nCompensation Discussion and Analysis 3. 2025 Executive Compensation Program Overview\n\n \n\nEnterprise Value Acceleration Program\n\nIn late 2025, we made incremental, one-time grants to our NEOs (other than Messrs. Newman and Wetherbee, who announced their planned retirements) and certain other members of our management team, primarily those in business unit-specific operational roles deemed critical to the execution of our strategies, under a new “Enterprise Value Acceleration” (“EVA”) program.\n\nThe EVA program was designed as a highly performance-contingent, multi-year incentive vehicle intended to reward only extraordinary and sustained stock price appreciation. The Committee carefully evaluated retention risks, competitive market dynamics, and stockholder alignment before approving these one-time awards. Importantly, no value will be realized under the program unless significant stock price hurdles are achieved and sustained over time. The Committee believes this structure appropriately balances retention objectives with strong performance safeguards and stockholder alignment.\n\nAwards under this program will vest, if at all, based on the Company’s stock price performance relative to pre-determined benchmarks over the course of a four-year performance period extending from January 1, 2026 through December 31, 2029. This four-year performance period creates a longer incentive and retention horizon than other components of our existing incentive programs, and the pre-determined stock price performance targets established for the program are significantly higher than the prevailing market price for our stock at the time the awards were granted. This means that EVA award recipients will only earn target or greater payouts under the program if our business delivers significant growth in shareholder value during the four-year performance period. Shares earned under the Enterprise Value Acceleration program, if any, will be payable to award recipients who remain employed by the Company in two equal installments in early 2030 and early 2031. For more discussion of the terms of our Enterprise Value Acceleration Awards see page 52.\n\nWhile we believe that, given their distinct and non-routine nature, these awards should be considered independently of our regular executive compensation program, 2025 target pay including these awards is more heavily weighted in favor of performance-contingent compensation, as illustrated by the following:\n\n2025 Target Pay Mix With Enterprise Value Acceleration Awards\n\n \n\n \n\n \n\n    \n\nPreview: PSU Changes for 2026\n\n \n\nFor 2026, we changed the design of our customary PSU awards to incorporate an additional performance metric. Specifically, PSU awards granted in early 2026 vest at the end of a three-year performance period based (a) 50% on the Company’s TSR relative to that of the Company’s compensation peer group, and (b) 50% based on year-over-year growth in EBITDA margin relative to pre-determined growth targets.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nCompensation Discussion and Analysis 4. Details of 2025 Executive Compensation Program\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n49 \n\n \n\n \n\n4.\n\n \nDETAILS OF 2025 EXECUTIVE COMPENSATION PROGRAM\n\nBase Salary\n\nThe Committee’s approach to compensation is to offer a base salary that is competitive with an identified benchmarking peer group of companies. Base salary is determined by market median data for each NEO’s respective position, individual performance and competitive pay positioning.\n\nFor 2025 and 2024, annual base salaries for our NEOs were as follows:\n\n \n\nNamed Executive Officer\n  \n2025 Base Salary Rate ($)1\n \n  \n2024 Base Salary Rate ($)2\n \n\nFields\n  \n \n950,000\n \n  \n \n862,500\n \n\nNewman\n  \n \n675,000\n \n  \n \n675,000\n \n\nBhatia\n  \n \n620,000\n \n  \n \n620,000\n \n\nWetherbee\n  \n \n500,000\n \n  \n \n895,000\n \n\nHarris\n  \n \n520,000\n \n  \n \n520,000\n \n\n \n\n1 \n\nMr. Wetherbee’s base salary rate decreased effective January 1, 2025, reflecting our 2024 CEO transition and the evolution of his continuing role.\n\n \n\n2 \n\nFor Ms. Fields and Mr. Wetherbee, represents weighted average base salary rate for 2024. For the first six months of 2024, Mr. Wetherbee had a base salary rate of $1,040,000 and Ms. Fields had a base salary rate of $800,000. In connection with our CEO transition effective July 1, 2024, Ms. Fields’s base salary rate increased to $900,000 and Mr. Wetherbee’s base salary rate decreased to $750,000. Effective October 1, 2024, Ms. Fields’s base salary rate increased to $950,000.\n\nShort-Term Incentive Program\n\nATI’s Annual Performance Plan (“APP”) is a short-term cash incentive plan in which approximately 400 key employees (including the NEOs) participate. For executive officers, 90% of the performance goals are based on financial metrics, and 10% are based on strategic/individual goals, as described below.\n\nAPP Performance Metrics\n\n \n\n \n\nPerformance Criteria. The performance goals for the 2025 APP were set in early 2025 based on ATI’s business and operations plans for 2025. Corporate-wide goals are established in a bottom-up process through which each business unit’s business plan and business conditions are separately reviewed, as are the expectations for other performance factors at each business unit.\n\nOur short-term incentive targets for 2025 exceeded our actual 2024 performance, reflecting our commitment to using our compensation structure to reward continued improvement. Targets set in early 2026 for our 2026 APP exceed 2025 results.\n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n50\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nCompensation Discussion and Analysis 4. Details of 2025 Executive Compensation Program\n\n \n\nLevel of Difficulty. The Committee sets the APP performance goals so that the relative difficulty of achieving the target level is consistent from year to year. The objective is to establish target goals that are challenging yet achievable, with a much higher level of difficulty to achieve performance that generates the maximum payout.\n\nAward Opportunities. Opportunities for the NEOs under the APP are expressed as a percentage of base salary. The Committee sets the potential award ranges for each NEO using comparative market data provided by our compensation consultant. In general, our short-term incentive program is designed so that the payout associated with achieving threshold performance for each performance goal is equal to 25% of target, while the payout associated with achieving the maximum performance level is capped at 200% of target. No payout with respect to the financial performance component is earned for performance below the threshold level.\n\nIndividual NEO Goals. 90% of each NEO’s annual award opportunity under the APP is determined based on performance criteria relating to the financial and/or operational performance of our business, as described above, and the remaining 10% of each NEO’s award is determined based on his or her personal performance relative to specific individual strategic goals. These goals are established early in the year and reviewed and approved by the Committee. Each NEO’s performance relative to his or her individual goals is evaluated at the end of the year, through a process that includes personal self-assessments, as well as input and recommendations from our CEO. These evaluations are reviewed by the Committee, which performs its own assessment of the personal performance of our Executive Chairman and of our CEO and determines the amount of each NEO award.\n\nFor 2025, half of each NEO’s 10% component focused on improving inventory management. The remainder of our NEOs’ goals focused on, among other strategic matters: growing the Company’s core business, particularly in aerospace and defense; the ongoing transformation of our business; developing great and engaging leaders; liquidity and capital allocation; and effective management of various risks facing our business.\n\nUnder our APP program, the Committee has expressly reserved the broad discretion to reduce or eliminate any APP award that may otherwise be payable to one or more participants, including each NEO, if the Committee believes any facet of ATI’s financial or operational performance is substandard, especially in relation to the Committee’s expectations for workplace safety, the environmental impact of our business or other aspects of our annual performance with the potential to affect the sustainability of our business. This discretion, coupled with the 10% personal goal component of our APP program, provides the Committee with flexibility to implement short-term incentives in a manner that, while largely designed to drive achievement of financial performance goals, also reflects our values and other qualitative considerations that are important to our business and our stakeholders.\n\n2025 APP Award Opportunities for NEOs\n\n \n\n \n  \n\nAnnual Incentive Opportunities\n\n(percentage of base salary)\n\n \n\nNamed Executive Officer*\n  \nBelow Threshold\n(0% of Target)\n \n    \n\nThreshold\n\n(25% of Target)\n\n \n    \n\nTarget\n\n(100% of Target)\n\n \n    \n\nMaximum\n\n(200% of Target)\n\n \n\nFields\n  \n \n0%\n \n    \n \n31.25%\n \n    \n \n125%\n \n    \n \n250%\n \n\nNewman\n  \n \n0%\n \n    \n \n20%\n \n    \n \n80%\n \n    \n \n160%\n \n\nBhatia and Harris\n  \n \n0%\n \n    \n \n17.5%\n \n    \n \n70%\n \n    \n \n140%\n \n\n \n\n*\n\nMr. Wetherbee did not participate in the 2025 APP but was eligible to receive an award of up to $500,000 at the discretion of the Committee based on its evaluation of his performance as Executive Chairman.\n\nTo calculate a potential award amount, the target percentage of salary for each NEO is multiplied by a formula based on performance.\n\nFormula\n\n \n\n \n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nCompensation Discussion and Analysis 4. Details of 2025 Executive Compensation Program\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n51 \n\n \n\nLong-Term Incentive Plan (“LTIP”)\n\nThe long-term incentive portion of our regular, annual compensation program generally has two components:\n\n \n\n◆\n \n\nPSUs: performance stock units that cliff vest based on the achievement of quantitative financial performance goals over a three-year performance period, subject to the recipient’s continued employment; and\n\n \n\n◆\n \n\nRSUs: restricted stock units that vest in three equal annual installments, provided that the recipient remains employed by ATI on the applicable vesting date.\n\nFor 2025, the LTIP was structured as shown below.\n\n \n\nVehicle\n\n \n \n \n\n \nPerformance\n \nVesting\n \nPayout Range\n\n \n\n \n \n \n\nPerformance\nStock Units\n\n(70%)\n\n \n\n \n\n \nRelative TSR\n \nCliff vesting following a 3-Year Performance Period\n \n\nThreshold = 25% of Target\n\nTarget = 100%\n\nMaximum = 200% of Target*\n\n \n\n* At the inception of the award period, the Committee can reduce the threshold and maximum payout levels at its discretion.\n\n \n\n \n \n\nRestricted\nStock Units\n\n30%\n\n \n\n \n\n \nN/A\n \n3-Year Ratable Vesting\n\n \n\nPerformance Stock Units\n\nPSUs awarded in January 2025 (“2025-2027 PSUs”) will vest following the conclusion of a three-year performance period ending on December 31, 2027, based on ATI’s TSR during the performance period relative to that of the pre-determined peer group described below.\n\n \n\n \n \n\n \n\nTSR PEER GROUP\n\n \n\n \n\n \n\n \n \n\n \n\n \n\nThe Committee reviewed many potential peer groups and indices and determined that the peer group we use to benchmark executive compensation was most appropriate. The use of the following peer group both for 2025 compensation benchmarking and for performance measurement for our 2025-2027 PSUs creates a direct link between pay and performance:\n\n \n\n \n\n \n\n \n\n◆\n\nBWX Technologies, Inc.\n\n \n\n◆\n\nCarpenter Technology Company\n\n \n\n◆\n\nCommercial Metals Company\n\n \n\n◆\n\nCurtiss-Wright Corporation\n\n \n\n◆\n\nDonaldson Company, Inc.\n\n \n\n◆\n\nDover Corporation\n\n \n\n \n\n◆\n\nHexcel Corporation\n\n \n\n◆\n\nHowmet Aerospace Inc.\n\n \n\n◆\n\nITT Inc.\n\n \n\n◆\n\nMaterion Corporation\n\n \n\n◆\n\nMoog Inc.\n\n \n\n◆\n\nRegal Rexnord Corporation\n\n \n\n◆\n\nSpirit AeroSystems Holdings Inc.\n\n \n\n◆\n\nThe Timken Company\n\n \n\n◆\n\nValmont Industries, Inc.\n\n \n\n◆\n\nWoodward, Inc.\n\n \n\n \n\nWhen vested, each PSU will convert into a share of the Company’s common stock. No dividends are accumulated or paid on the PSUs granted in 2025.\n\nPerformance Measurement\n\nShares of ATI common stock underlying these awards may be earned over the course of four individual performance measurement periods within the three-year performance period but will not be paid out until the full three-year performance period has concluded. The first measurement period concludes on June 30, 2026, corresponding with the end of the first six quarters covered by the three-year period. The remaining three measurement periods conclude on December 31, 2026, June 30, 2027, and December 31, 2027. This structure was specifically designed to create incentives for sustained focus and continuous drive for improvement throughout the three-year performance period. The Committee’s goal was to encourage both shorter-term and long-term outperformance relative to our peer group, which we believe more effectively creates direct alignment with stockholder expectations over the entire performance period. This approach has an additional benefit of mitigating some shorter-term volatility and is a better reflection of our aggregate performance over the entire three-year performance period.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n52\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nCompensation Discussion and Analysis 4. Details of 2025 Executive Compensation Program\n\n \n\nAward Vesting and Payment\n\nBased on market practices and our desired objectives, we structured the payment scale for these awards to require 2nd quartile performance for a threshold payout and top quartile performance for a maximum payout. The proportion of each award that may be earned with respect to each measurement period is more heavily weighted toward the end of the three-year performance period to encourage sustained performance. Specifically, 20% of the target amount of each award may be earned for each of the first two measurement periods, and 30% may be earned for each of the third and fourth measurement periods, in each case according to the following scale:\n\n \n\nIf our relative TSR for a measurement period falls between the threshold and target levels of achievement, or between the target and maximum levels of achievement, then the percentage of the payout that is earned and vested will be interpolated between the percentages shown above on a straight-line basis.\n\nNegative TSR Cap\n\nThe Committee believes it is important for payouts under our long-term incentive program to align with stockholder interests. Accordingly, if our absolute TSR for the three-year performance period ending December 31, 2027, is negative, then the total payout for the 2025-2027 PSUs may not exceed 100%, regardless of our relative TSR.\n\nRestricted Stock Units\n\nRSUs granted under the LTIP vest in equal annual installments on each of the first three anniversaries of their grant date, as long as the award recipient remains an employee of the Company on the relevant vesting date. If and when vested, each RSU converts into a share of Company common stock. No dividends accumulate or are paid on the RSUs.\n\nEnterprise Value Acceleration Awards\n\nIn late 2025, we made incremental, one-time grants to our NEOs (other than Messrs. Newman and Wetherbee, who announced their planned retirements) and certain other members of our management team, primarily those in business unit-specific operational roles deemed critical to the execution of our strategies, under a new “Enterprise Value Acceleration” program.\n\nThe EVA program was designed as a highly performance-contingent, multi-year incentive vehicle intended to reward only extraordinary and sustained stock price appreciation. The Committee carefully evaluated retention risks, competitive market dynamics, and stockholder alignment before approving these one-time awards. Importantly, no value will be realized under the program unless significant stock price hurdles are achieved and sustained over time. The Committee believes this structure appropriately balances retention objectives with strong performance safeguards and stockholder alignment.\n\nThe EVA program is designed to pay out to participants if our stock price increases significantly, generating meaningful shareholder return. Specifically:\n\n \n\n◆\n \n\nEach award under the EVA Plan entitles its recipient to receive shares of ATI stock following the end of a four-year performance period from January 1, 2026, to December 31, 2029, if ATI’s stock price achieves certain price targets, generally so long as the recipient remains an ATI employee.\n\n \n\n◆\n \n\nEach price target is deemed to have been achieved – and the portion of each award attributed to that target will be earned — if at any time during the performance period, the 10-day trailing average trading price for a share of ATI stock on the NYSE (the “EVA Average Price”) meets or exceeds the target for at least 20 consecutive trading days. We believe this measurement approach assures that our stock price has achieved the targeted levels for meaningful periods of time, and that shares are not earned for only short-term performance achievement.\n\n \n\n◆\n \n\nEach award recipient has the opportunity to earn a number of shares of ATI common stock ranging from 0% to 300% of his or her target award, depending on how our stock performs during the four-year performance period ending on December 31, 2029. Specifically, award recipients will earn the target award if the EVA Average Price is at least $135 per share during any consecutive 20-day trading days during the performance period, and have the opportunity to earn additional shares if the EVA Average Price meets or exceeds higher incremental price targets. Award recipients will earn the maximum award of 300% of target if the EVA Average Price is at least $195 per share during any consecutive 20-day trading days during the performance period, provided that, if the EVA Average Price for the ten trading-day period concluding on December 31, 2029, is greater than $300 per share, the number of shares payable upon vesting will be capped at a number equal to the product of the maximum number of shares otherwise payable and $300, divided by the EVA\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nCompensation Discussion and Analysis 4. Details of 2025 Executive Compensation Program\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n53 \n\n \n\n \n\nAverage Price as of December 31, 2029. Further, if our absolute TSR at the end of the performance period is negative (as calculated according to the terms of the applicable award agreement), award payouts will be capped at target, regardless of any other level of achievement during the performance period.\n\n \n\n◆\n \n\nShares earned with respect to any award will vest and be paid to each award recipient in two equal installments in early 2030 and early 2031, provided the recipient remains employed by ATI on the relevant payment date. Generally, award recipients who cease to be employed by ATI prior to full settlement for any reason other than death, disability or retirement will forfeit any earned but unpaid shares.\n\nThe Committee believes that this program will drive engagement and provide important incentives to our senior management and other key members of the Company’s leadership to creatively and consistently pursue achievement of our most important and transformational strategic goals, supporting value creation over a meaningful time horizon.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n54\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nCompensation Discussion and Analysis 5. 2025 Business and Compensation Program Results\n\n \n\n5.\n\n \n2025 BUSINESS AND COMPENSATION PROGRAM RESULTS\n\nOur 2025 Business Performance\n\nATI continued its strong performance trajectory in 2025. With our focused commitment to doing what we say we are going to do and solving our customers’ most difficult challenges, we created opportunities in the face of the ongoing global geopolitical, supply chain and other challenges that continue to impact our current environment. At the same time, we captured new market share and sharpened our operational advantage to drive shareholder value. We continued to successfully execute our strategy by capitalizing on the opportunities presented by unprecedented demand growth, particularly in our core aerospace and defense markets.\n\nFinancial and Operational Performance\n\n \n\n \n\nWe believe that the strategic and operational changes we have achieved in recent years and continue to pursue are positioning our business for success in 2026 and beyond and are driving our ability to create shareholder value. The following charts illustrate ATI’s TSR compared to the S&P 500 in 2025 and since the beginning of 2023:\n\n \n\n \n\nKey Achievements\n\n \n\n \n\n \n\nSales of $4.6 billion compared to $4.4 billion in 2024\n\n \n\n \n◆\n \nHighest annual sales in more than a decade\n \n\n \n\n \n◆\n \nAerospace and defense accounted for approximately 68%\n \n\nGross profit of $1 billion compared to $898 million in 2024\n\nNet income of $404 million, compared to $383 million in 2024\n\nOperating cash flow of $614 million compared to $407 million in 2024\n\nStrong liquidity and cash position. $417 million of cash on hand at year-end\n\nReturning capital to stockholders. Repurchased $470 million of our outstanding stock\n\n \n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nCompensation Discussion and Analysis 5. 2025 Business and Compensation Program Results\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n55 \n\n \n\nShort-Term Incentive Compensation Program Results\n\n2025 APP Target and Earned Amounts for Each NEO\n\n \n\n \n  \nAt Target\n \n  \n \n \n  \nActual\n \n\nNamed Executive Officer1\n  \nTarget\n(% of Base Salary)(2)\n \n    \nTarget Dollar\nAmount ($)\n \n  \n  \n \n\n \n  \n\nActual Weighted\n\nAchievement\n\n(% of Target\nEarned)\n\n \n    \nEarned/Paid\nCash Award ($)\n \n\nFields\n  \n \n125\n \n    \n \n1,187,500\n \n  \n \n \n \n  \n \n193.3\n \n    \n \n2,295,794\n \n\nNewman\n  \n \n80\n \n    \n \n540,000\n \n  \n \n \n \n  \n \n193.3\n \n    \n \n1,043,982\n \n\nBhatia\n  \n \n70\n \n    \n \n434,000\n \n  \n \n \n \n  \n \n190.6\n \n    \n \n827,117\n \n\nHarris\n  \n \n70\n \n    \n \n364,000\n \n  \n \n \n \n  \n \n194.6\n \n    \n \n708,271\n \n\n \n\n1 \n\nMr. Wetherbee did not participate in the 2025 APP but was eligible to receive an award of up to $500,000 at the discretion of the Board based on its evaluation of his performance as Executive Chairman.\n\n2 \n\nBase salary earned for 2025 was $950,000 for Ms. Fields, $675,000 for Mr. Newman, $620,000 for Ms. Bhatia and $520,000 for Mr. Harris.\n\nThe 2025 APP award for each of our NEOs was determined by (a) total ATI performance relative to the financial metrics and (b) each NEO’s individual performance relative to individual strategic goals, including a focus on improved inventory management. Our 2025 goals exceeded our actual 2024 performance. For further discussion of these metrics, including the nature of our NEOs’ 2025 individual strategic goals, see page 50 of this Proxy Statement. For further information about ATI’s financial performance, please see ATI’s Annual Report on Form 10-K for the fiscal year ended December 28, 2025 filed with the SEC. The following tables describe the relative weighting of each metric and the individual goals, as well as ATI’s and each executive’s relative level of achievement for the year:\n\n \n\n \n \n \n \n    \n($ in millions)\n \n    \n \n \n\nFinancial\n\nPerformance Goals\n\n \n\nRelative Weighting\n\n(% of Total Award)\n\n \n    \nThreshold\n \n    \nTarget\n \n    \nMaximum\n \n    \n\n2025 Actual\n\nPerformance\n\n \n    \n\n2025 Actual\n\nAchievement\n\n(% of Goal Target)\n\n \n\nATI EBITDA\n \n \n60\n \n    \n \n725\n \n    \n \n800\n \n    \n \n860\n \n    \n \n859\n \n    \n \n198.8%\n \n\nATI Free Cash Flow\n \n \n30\n \n    \n \n210\n \n    \n \n275\n \n    \n \n350\n \n    \n \n380\n \n    \n \n200.0%\n \n\nAggregate Financial Performance\n \n \n90\n \n    \n \n \n \n    \n \n \n \n    \n \n \n \n    \n \n \n \n    \n \n \n \n\n \n\nNamed Executive Officer\n  \n\nFinancial Performance\n\nGoals (90%)\n\n \n    \n\nStrategic/Individual\n\nGoals (10%)\n\n \n    \n\nTotal 2025\n\nAchievement (%)\n\n \n    \n\nTotal 2025\n\nAchievement ($)\n\n \n\nFields\n  \n \n199.2%\n \n    \n \n175%\n \n    \n \n193.3\n \n    \n \n2,295,794\n \n\nNewman\n  \n \n199.2%\n \n    \n \n175%\n \n    \n \n193.3\n \n    \n \n1,043,982\n \n\nBhatia\n  \n \n199.2%\n \n    \n \n120%\n \n    \n \n190.6\n \n    \n \n827,117\n \n\nHarris\n  \n \n199.2%\n \n    \n \n200%\n \n    \n \n194.6\n \n    \n \n708,271\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n56\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nCompensation Discussion and Analysis 5. 2025 Business and Compensation Program Results\n\n \n\nLong-Term Incentive Compensation Program Results\n\n2023-2025 Performance-Vested Restricted Stock Units\n\nPSUs awarded in 2023 vested as of December 31, 2025, based on ATI’s total shareholder return relative to that of our previously-disclosed legacy peer group. Shares of ATI common stock underlying these awards were earned over the course of four individual performance measurement periods within the three-year performance period. The first measurement period concluded on June 30, 2024, corresponding with the end of the first six quarters covered by the three-year period. The remaining three measurement periods concluded on December 31, 2024, June 30, 2025, and December 31, 2025. The awards were structured such that 20% of each award could be earned with respect to each of the first two measurement periods, and 30% of each award could be earned with respect to each of the final two measurement periods according to the following scale:\n\n \n\nBased on this structure and ATI’s relative total shareholder return for each of the four measurement periods, our 2023-2025 PSUs settled in January 2025 at 195.6% of target as illustrated below:\n\nATI TSR Positioning vs. Compensation Peer Group FY 2023 - 2025 by Quarter, Cumulative\n\n \n\n \n\nNote:\n\nMarch‘23-March’24 shown for reference only\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nCompensation Discussion and Analysis 5. 2025 Business and Compensation Program Results\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n57 \n\n \n\n2022-2025 Breakout Performance Program Results\n\nThe Breakout Performance awards granted in 2022 vested based on ATI’s absolute TSR relative to pre-determined stock price benchmarks over the course of a four-year performance period extending from January 1, 2022, through December 31, 2024, creating a longer incentive and retention horizon than other components of our existing incentive programs. These awards were structured with demanding multi-year stock price thresholds and no guaranteed payout. Potential outcomes ranged from 0 to 300% of the target awards and were entirely subject to the performance of our stock over the four-year performance period. The awards further provided that, if the 20-day trailing average trading price for ATI’s common stock for the 20-trading day period concluding with December 31, 2025 (the “Average Price”) were $100 or more per share, the number of shares payable upon vesting would be capped at a number equal to the product of the maximum number of shares otherwise payable and $100, divided by the Average Price.\n\nOne-half of the resulting shares underlying these awards vested and became payable on December 31, 2025, and the remaining half are scheduled to vest on December 31, 2026, and will be paid in early 2027, generally subject to the applicable award recipient’s continued employment. Award recipients who cease to be employed by ATI prior to full settlement for any reason other than death, disability or retirement generally will forfeit any earned but unpaid shares.    \n\nThe Average Price for ATI’s stock achieved the final price target of $65 per share on June 17, 2025, earning the maximum award payout. As of December 31, 2025, the Average Price for a share of ATI stock on the NYSE was $109.20, exceeding the applicable $100 cap. Consequently, recipients became entitled to receive a number of shares equal to approximately 275% of their target awards. One-half of these awards was paid in early 2026, and the remaining half will become payable in early 2027, subject to the terms and conditions of the awards. \n\nWhile payouts in 2025 reflect strong performance over the applicable four-year measurement period, the Committee notes that these awards were granted several years ago as part of a transformational strategy and were contingent on sustained stockholder value creation.\n\nThe Committee continues to evaluate the appropriateness of incentive magnitude relative to performance outcomes and stockholder experience.\n\nATI’s 2025 Performance Impact on NEO Compensation\n\nMulti-Year Trends Reflect Our Pay-For-Performance Culture\n\nThe compensation of our senior executives during 2025 reflects their successful execution of our 2025 priorities and other strategic initiatives. Prior-years’ results reflect cyclical fluctuations in business performance, further demonstrating our pay for performance culture.\n\n \n\n◆\n \n\n2024 and 2023 Short-term incentive payments were above target, but meaningfully below the maximum potential payout: Our NEOs received short-term incentive payments under our annual incentive plan for 2024 that ranged from approximately 100% to 147% of their respective target awards, following similar payout levels for 2023. These outcomes reflect both our outstanding business performance and our executives’ meaningful personal achievement over the course of both 2024 and 2023, as well as the highly challenging nature of the levels of performance we established for both target and maximum payouts under program.\n\n \n\n◆\n \n\nMulti-year trends in short-term incentive reflect the cyclicality of our business and our commitment to pay for performance: While awards under our short-term incentive program were meaningfully above target for the last five years, reflecting recent successes, awards under our 2020 short term incentive program were significantly below target, reflecting the sudden and widespread impact of the pandemic and related economic downturn, as well as our decision to refrain from adjusting our performance goals downward despite the sudden and unanticipated nature of the pandemic and its effects. Our 2019 and 2018 payment of short-term incentive awards at greater-than-target levels followed near-target payments for 2017 and payments for 2016 and 2015 that were either zero or significantly below target. This trend reflects the cyclical nature of our business and strong correlation between pay and performance inherent in our programs.\n\n \n\n◆\n \n\nLong-term incentive results similarly reflect cyclical challenges: Notably, as we sought to transform our business over the last several years, the results of our long-term compensation programs also contributed at times to below-target annual compensation for our NEOs. Specifically, while our 2021-2023 PSUs, 2022-2024 PSUs, and 2023-2025 PSUs paid at or near their maximum level of achievement, a substantial portion of the long-term incentive awards granted to our NEOs for the performance periods ended in preceding years did not vest, because the applicable performance criteria (including market performance) were not satisfied. As a consequence, our NEOs’ aggregate realized compensation was lower than their target total annual compensation for several years prior to 2024. Specifically, our 2018 – 2020 awards, 2019 – 2021 awards and 2020 – 2022 awards settled at only 68.9%, 23.7% and 31.1% of target, respectively.\n\n2025 NEO Total Realized Compensation\n\nWhen making determinations and awards under our incentive plans, the Compensation and Leadership Development Committee considers both target compensation and the actual dollar value of awards to be delivered to the NEOs in any given year, or “total realized compensation.” Total realized compensation for 2025 reflects the culmination of multi-year performance cycles that began several years ago and were earned only after sustained achievement of pre-established, quantitative financial and total shareholder return metrics. The Committee recognizes that certain realized amounts may appear elevated in a single reporting year due to the vesting of long-term awards covering three- and four-year performance periods.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n58\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nCompensation Discussion and Analysis 5. 2025 Business and Compensation Program Results\n\n \n\nThese outcomes, which were not guaranteed and were subject to both absolute and relative performance hurdles, reflect:\n\n \n\n◆\n \n\nour executive compensation program’s strong emphasis on, and alignment with, the performance of our business;\n\n \n\n◆\n \n\nthe success of our leadership’s focus on key markets, high margin products and operational excellence; and\n\n \n\n◆\n \n\nthe resulting stand-out performance of our stock on both an absolute basis and relative to our peer group.\n\nThe Committee continues to evaluate compensation levels carefully to ensure alignment with stockholder experience, peer market practices, internal pay equity considerations, and responsible stewardship of Company resources.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nCompensation Discussion and Analysis\n\n 6. Other Compensation Practices and Policies\n\n \n\n \n\nATI\n\n 2026 Proxy Statement\n\n \n \n \n\n \n\n59 \n\n \n\n6.\n\n \n\nOTHER COMPENSATION PRACTICES AND POLICIES\n\nStock Ownership Guidelines\n\nThe Company maintains the following robust stock ownership guidelines for its executives, including the NEOs. These guidelines are designed to further link these executives’ interests with the interests of stockholders generally:\n\n \n\n \n\nExecutives are required to retain 50% of the\nafter-tax\nvalue of shares issued upon the vesting of equity awards until the ownership requirement is satisfied.\n\nEach executive subject to the guidelines has five years from the date of his or her appointment to one of the designated positions to meet the applicable ownership guideline. Our CEO and each other NEO currently meets his or her ownership obligations under the guidelines.\n\nContinuing NEO Stock Ownership Guidelines Compliance*\n\n \n\n \n\n \n\n \n\n*\n\nReflects March 16, 2026, closing price for ATI common stock on the NYSE of $\n147.48\nper share.\n\nNo Hedging or Pledging of Stock\n\nATI policy prohibits directors, officers and key employees from engaging in publicly traded options and hedging transactions with regard to ATI securities. ATI policies also prohibit our officers and directors from pledging ATI stock to secure personal loans.\n\nInsider Trading Policies and Procedures\n\nThe Company has \nadopted\n an insider trading policy governing the purchase, sale, and/or disposition of its securities by its directors, officers, employees, and other covered persons. The Company believes this policy is reasonably designed to promote compliance with insider trading laws, rules, and regulations, and the NYSE listing standards. A copy of this policy is filed as Exhibit 19.1 to our 2025 Annual Report on Form\n10-K\nfor the fiscal year ended December 28, 2025. Additionally, the Company’s policy is to only engage in transactions of Company securities in compliance with insider trading laws.\n\nAdherence to Ethical Standards; Clawback Policies\n\nIncentive awards (paid in cash or equity) are conditioned on adherence to the Company’s Code of Conduct, which is published on our website\n\nATImaterials.com\n\n. We have clawback provisions in our 2022 Incentive Plan that provide for the return of incentive compensation to the extent that information used to calculate achievement of earnings or other performance measures is subsequently determined to have been materially incorrect (including but not limited to circumstances under which any such inaccuracy results in a financial restatement). Additionally, in 2023 we adopted ATI’s Executive Compensation Recovery Policy, which provides for the recovery of any erroneously awarded incentive-based compensation from our NEOs and certain other senior executives in the event of a financial restatement due to material\nnon-compliance\nwith financial reporting requirements, as required by applicable SEC and NYSE rules.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n60\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nCompensation Discussion and Analysis 6. Other Compensation Practices and Policies\n\n \n\nEmployment Agreements; Change in Control Agreements\n\nATI does not have any employment agreements with its NEOs.\n\nThe Company has change in control agreements with each NEO and certain other executives that provide for severance payments in the event the executive is terminated in connection with a change in control, as defined in and provided by the agreements. These change in control agreements do not include an excise tax gross-up provision. The change in control agreements are intended to better enable ATI to retain NEOs in the event that it is the subject of a potential change in control transaction and to provide a level of financial security intended to help our leadership team maintain focus and productivity. Based on advice from its compensation consultant, the Committee believes that the potential payments under these agreements are, individually and in the aggregate, in line with competitive practices.\n\nFor a more detailed discussion of these agreements, see the “Employment and Change in Control Agreements” section of this Proxy Statement.\n\nPension and Retirement Plans\n\nATI maintains qualified defined benefit pension plans, which have a number of benefit formulas that apply separately to various groups of employees and retirees. Effective December 31, 2014, the Company froze future benefit accruals in the ATI Pension Plan for all participating employees other than those in collectively bargained employment arrangements. Also, effective December 31, 2014, the Company froze the defined benefit-type non-qualified deferred compensation plans in which certain salaried employees participate, which includes the defined benefit portion of the ATI Benefit Restoration Plan in which Mr. Wetherbee participated. The Company continues to sponsor a qualified defined contribution plan and a non-qualified defined contribution restoration plan aimed at compensating for the effects of limitations on defined contribution accruals imposed by the U.S. Internal Revenue Code (the “Code”). For more information regarding the pension plans, see the Pension Benefits table and accompanying narrative.\n\nPerquisites\n\nATI does not generally provide our executives with perquisites, such as the personal use of corporate aircraft without reimbursement to the Company, payment of club membership dues or tax reimbursement arrangements. ATI does provide a parking benefit to the NEOs who work at corporate headquarters on the same terms as provided to a broader group of corporate employees.\n\nCOMPENSATION COMMITTEE REPORT\n\nThe Compensation and Leadership Development Committee has reviewed and discussed the preceding Compensation Discussion and Analysis with Company management. Based on this review and discussion, the Committee recommends to the Board of Directors that the Compensation Discussion and Analysis be included in the Company’s 2026 Proxy Statement. The Committee furnishes this Report for inclusion in the 2026 Proxy Statement and recommends its inclusion in ATI’s Annual Report on Form 10-K.\n\nSubmitted by:\n\nCompensation and Leadership Development Committee\n\n \n\nChair:\n \nCarolyn Corvi, Chair\n\nMembers: \n \nHerbert J. Carlisle\n\n \n\nJ. Brett Harvey\n\nDavid P. Hess\n\nMarianne Kah\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nCompensation Discussion and Analysis Summary Compensation Table for 2025\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n61 \n\n \n\nSUMMARY COMPENSATION TABLE FOR 2025\n\nThe following Summary Compensation Table sets forth information about the compensation paid by the Company to the persons who served as the Chief Executive Officer or Chief Financial Officer during 2025 and each of the other three most highly compensated executives who were serving as executive officers as of December 31, 2025.\n\n \n\nName and Principal Position\n \nYear\n \n \nSalary\n($)\n \n \nBonus\n($)(1)\n \n \nStock\nAwards\n($)(2)\n \n \nNon-Equity\nIncentive Plan\nCompensation\n($)(3)\n \n \nChange in\nPension Value and\nNon-Qualified Deferred\nCompensation Earnings\n($)(4)\n \n \nAll Other\nCompensation\n($)(5)\n \n \nTotal\n($)\n \n\nKimberly A. Fields\n \n \n2025\n \n \n \n950,000\n \n \n \n—\n \n \n \n10,051,700\n \n \n \n2,295,794\n \n \n \n—\n \n \n \n215,243\n \n \n \n13,512,737\n \n\nPresident, CEO and Chair-Elect\n \n \n2024\n \n \n \n855,769\n \n \n \n—\n \n \n \n3,461,225\n \n \n \n1,422,302\n \n \n \n—\n \n \n \n152,521\n \n \n \n5,891,817\n \n\n \n \n \n2023\n \n \n \n726,538\n \n \n \n—\n \n \n \n2,118,819\n \n \n \n957,214\n \n \n \n—\n \n \n \n164,416\n \n \n \n3,996,987\n \n\nDonald P. Newman(6)\n \n \n2025\n \n \n \n675,000\n \n \n \n—\n \n \n \n1,803,883\n \n \n \n1,043,982\n \n \n \n—\n \n \n \n139,389\n \n \n \n3,662,254\n \n\nFormer EVP, Finance and CFO\n \n \n2024\n \n \n \n673,269\n \n \n \n—\n \n \n \n1,677,552\n \n \n \n792,303\n \n \n \n—\n \n \n \n117,113\n \n \n \n3,260,237\n \n\n \n \n2023\n \n \n \n628,846\n \n \n \n—\n \n \n \n1,654,456\n \n \n \n670,853\n \n \n \n—\n \n \n \n130,998\n \n \n \n3,085,153\n \n\nVaishali S. Bhatia(7)\n \n \n2025\n \n \n \n620,000\n \n \n \n300,000\n \n \n \n2,637,607\n \n \n \n827,117\n \n \n \n—\n \n \n \n79,695\n \n \n \n4,464,419\n \n\nSVP, General Counsel & CCO\n \n \n2024\n \n \n \n460,231\n \n \n \n700,000\n \n \n \n3,784,007\n \n \n \n464,235\n \n \n \n—\n \n \n \n31,853\n \n \n \n5,440,325\n \n\nTimothy J. Harris\n \n \n2025\n \n \n \n520,000\n \n \n \n—\n \n \n \n2,405,242\n \n \n \n708,271\n \n \n \n—\n \n \n \n93,755\n \n \n \n3,727,268\n \n\nSVP and CDIO\n \n \n2024\n \n \n \n519,231\n \n \n \n—\n \n \n \n1,174,830\n \n \n \n526,474\n \n \n \n—\n \n \n \n80,965\n \n \n \n2,301,500\n \n\n \n \n2023\n \n \n \n498,846\n \n \n \n—\n \n \n \n1,193,696\n \n \n \n460,061\n \n \n \n—\n \n \n \n91,877\n \n \n \n2,244,480\n \n\nRobert S. Wetherbee\n \n \n2025\n \n \n \n511,538\n \n \n \n500,000\n \n \n \n999,992\n \n \n \n—\n \n \n \n(3,753\n) \n \n \n220,872\n \n \n \n2,228,649\n \n\nExecutive Chairman\n \n \n2024\n \n \n \n903,654\n \n \n \n—\n \n \n \n4,518,727\n \n \n \n1,514,420\n \n \n \n5,076\n \n \n \n231,884\n \n \n \n7,173,761\n \n\n \n \n \n2023\n \n \n \n973,077\n \n \n \n—\n \n \n \n4,774,796\n \n \n \n1,632,945\n \n \n \n17,259\n \n \n \n272,477\n \n \n \n7,670,554\n \n\n \n\n(1)\n\nBonus: The amounts shown in this column for 2025 include the final installment of a signing bonus paid to Ms. Bhatia and a one-time short-term incentive awarded by the Board to Mr. Wetherbee in lieu of his participation in the 2025 APP.\n\n \n\n(2)\n\nStock Awards: The values in this column for 2025 are based on the aggregate grant date fair value, determined in accordance with FASB ASC Topic 718, of awards made under the Company’s LTIP in 2025. Regular 2025 LTIP awards for our NEOs were comprised 70% of PSUs and 30% of time-vested RSUs. The PSUs vest based on the Company’s TSR over a three-year performance period relative to that of a predetermined peer group. The RSUs vest over three years based on employment service, with one-third of the award vesting on each of the first, second and third anniversaries of the grant date. Grant date fair values of the PSU awards are calculated based on the expected outcome of the related performance conditions to which the awards are subject, as applicable. If maximum performance were to be achieved, the 2025 amounts (including both RSUs and PSUs) for each NEO would be as follows: Ms. Fields, $25,038,304; Mr. Newman, $3,142,053; Ms. Bhatia, $6,100,134; Mr. Harris, $5,695,385 and Mr. Wetherbee, $999,992. Fair values for the PSU awards at target were estimated using Monte Carlo simulations of stock price correlation, projected dividend yields and other variables over three-year time horizons matching the PSU performance measurement period. The fair value of nonvested restricted stock unit awards, or RSUs, are measured based on the stock price at the grant date. For the 2025 RSU awards under the LTIP, the values were calculated using the average of the high and low trading prices of the Company’s common stock on the date of grant (January 3, 2025), which was $56.11. In addition, Ms. Fields, Ms. Bhatia and Mr. Harris received one-time grants in 2025 under our Enterprise Value Acceleration program. Awards under this program vest, if at all, based on the extent to which the Company’s stock price achieves certain pre-determined targets over the course of a four-year performance period ending December 31, 2029, and will become payable in two equal installments in early 2030 and 2031, provided in the case of each award recipient that he or she remains employed by the Company on the scheduled payment date. Fair values for awards under the Enterprise Value Acceleration, or “EVA”, program were $175.06 per share. The EVA program was designed as a highly performance-contingent, multi-year incentive vehicle intended to award only extraordinary and sustained stock price appreciation. No value will be realized under the program unless significant stock price hurdles are achieved and sustained over time. See pages 48 and 53 of this Proxy Statement and Note 16 to the financial statements in the Company’s Annual Report on Form 10-K for the fiscal year ended December 28, 2025, for further information.\n\n \n\n(3)\n\nNon-equity Incentive Plan Compensation: Consists of performance-based (and not discretionary) cash awards paid under the 2025 APP.\n\n \n\n(4)\n\nChanges in Pension Value and Non-Qualified Deferred Compensation Earnings: The amounts reflect the actuarial change in the present value of the NEO’s benefits under all defined benefit pension plans established by the Company, determined using interest rate and mortality rate assumptions consistent with those used in the Company’s financial statements. Effective December 31, 2014, the Company froze future benefit accruals in the ATI Pension Plan for all participating employees other than those in contractual employment arrangements. Also effective December 31, 2014, the Company froze the defined benefit-type non-qualified deferred compensation plans in which salaried employees participate, which includes the defined benefit portion of the ATI Benefit Restoration Plan in which Mr. Wetherbee participated. ATI Pension Plan 2, in which Mr. Wetherbee participated, was terminated effective December 31, 2022. In connection with the termination, Mr. Wetherbee elected to receive a lump sum benefit that was paid to him in 2023. See “Pension Benefits” on pages 65 and 66 of this Proxy Statement for more information.\n\n \n\n(5)\n\nAll Other Compensation: The values of any perquisites are calculated based on the aggregate incremental cost to the Company. The Company does not provide perquisites or personal benefits such as air travel or club memberships, or tax reimbursements relating to perquisites or personal benefits. Please see the All Other Compensation Table for 2025 that follows for additional information.\n\n \n\n(6)\n\nRetired CFO: Mr. Newman served as CFO throughout 2025 and retired from that role as of December 31, 2025. Our current CFO was appointed effective as of January 1, 2026.\n\n \n\n(7)\n\nNew NEO: Ms. Bhatia was a NEO for 2024 and 2025.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n62\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nCompensation Discussion and Analysis Summary Compensation Table for 2025\n\n \n\nAll Other Compensation for 2025\n\nAmounts in the “All Other Compensation Column” include the following:\n\n \n\nName\n  \nNonqualified Defined\nContribution Plans\n($)(1)\n \n    \nContributions made by\nthe Company to 401(k)\nand Other Defined\nContribution Plans\n($)\n \n    \nInsurance\nPremiums\n($)\n \n    \nOther\n($)\n \n    \nTotal\n($)\n \n\nKimberly A. Fields\n  \n \n178,213\n \n    \n \n28,000\n \n    \n \n9,030\n \n    \n \n—\n \n    \n \n215,243\n \n\nDonald P. Newman\n  \n \n100,084\n \n    \n \n28,000\n \n    \n \n10,296\n \n    \n \n1,009\n \n    \n \n139,389\n \n\nVaishali S. Bhatia\n  \n \n50,267\n \n    \n \n28,000\n \n    \n \n1,428\n \n    \n \n—\n \n    \n \n79,695\n \n\nTimothy J. Harris\n  \n \n63,023\n \n    \n \n28,000\n \n    \n \n2,732\n \n    \n \n—\n \n    \n \n93,755\n \n\nRobert S. Wetherbee\n  \n \n170,774\n \n    \n \n28,000\n \n    \n \n22,098\n \n    \n \n—\n \n    \n \n220,872\n \n\n \n\n(1)\n\nAmounts relate to the Defined Contribution Restoration Plan. Under the Defined Contribution Restoration Plan, the Company supplements payments received by participants under the Company’s defined contribution plan by accruing benefits on behalf of participants in amounts that are equivalent to the portion of the formula contributions or benefits that cannot be made under such plan due to limitations imposed by the Code. See also the narrative discussion preceding the Non-Qualified Deferred Compensation Table.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nCompensation Discussion and Analysis Grants of Plan-Based Awards for 2025\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n63 \n\n \n\nGRANTS OF PLAN-BASED AWARDS FOR 2025\n\n \n\n \n \n \n \n \n \n \nEstimated\nPossible Payouts\nUnder Non-Equity\nIncentive Plan Awards\n \n \nEstimated\nFuture Payouts\nUnder Equity\nIncentive Plan Awards\n \n \nAll Other\nStock\nAwards:\n \n \nAll Other\nOption\nAwards:\nNumber of\n \n \nExercise\nOr\nBase\n \n \nGrant Date\nFair Value of\n \n\nName\n \nDescription(1)\n \nGrant Date\n \n \nThreshold\n($)\n \n \nTarget\n($)\n \n \nMaximum\n($)\n \n \nThreshold\n(#)\n \n \nTarget\n(#)\n \n \nMaximum\n(#)\n \n \nNumber of\nShares\nof Stock\n(#)\n \n \nSecurities\nUnderlying\nOptions\n(#)\n \n \nPrice of\nOption\nAwards\n($/sh)\n \n \nPlan-Based\nEquity\nAwards\n($)(2)\n \n\nFields\n \nAPP\n \n\n \n \n593,750\n \n \n \n1,187,500\n \n \n \n2,375,000\n \n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \nEVA\n \n \n12/5/2025\n \n \n\n \n\n \n\n \n \nN/A\n \n \n \n34,188\n \n \n \n102,564\n \n \n\n \n\n \n\n \n \n5,984,890\n \n\n \nPSU\n \n \n1/3/2025\n \n \n\n \n\n \n\n \n \n21,832\n \n \n \n43,664\n \n \n \n87,328\n \n \n\n \n\n \n\n \n \n3,016,824\n \n\n \nRSU\n \n \n1/3/2025\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n18,713\n \n \n\n \n\n \n \n1,049,986\n \n\n \n \n\n \nTotal\n \n \n \n\n \n \n\n \n \n\n \n \n593,750\n \n \n \n1,187,500\n \n \n \n2,375,000\n \n \n \n21,832\n \n \n \n77,852\n \n \n \n189,892\n \n \n \n18,713\n \n \n \n \n\n \n \n\n \n \n\n \n \n \n\n \n \n\n \n \n\n \n \n10,051,700\n \n\nNewman\n \nAPP\n \n\n \n \n270,000\n \n \n \n540,000\n \n \n \n1,080,000\n \n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \nPSU\n \n \n1/3/2025\n \n \n\n \n\n \n\n \n \n9,684\n \n \n \n19,368\n \n \n \n38,736\n \n \n\n \n\n \n\n \n \n1,338,170\n \n\n \nRSU\n \n \n1/3/2025\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n8,300\n \n \n\n \n\n \n \n465,713\n \n\n \n \n\n \nTotal\n \n \n \n\n \n \n\n \n \n\n \n \n270,000\n \n \n \n540,000\n \n \n \n1,080,000\n \n \n \n9,684\n \n \n \n19,368\n \n \n \n38,736\n \n \n \n8,300\n \n \n \n \n\n \n \n\n \n \n\n \n \n \n\n \n \n\n \n \n\n \n \n1,803,883\n \n\nBhatia\n \nAPP\n \n\n \n \n217,000\n \n \n \n434,000\n \n \n \n868,000\n \n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \nEVA\n \n \n12/5/2025\n \n \n\n \n\n \n\n \n \nN/A\n \n \n \n6,837\n \n \n \n20,511\n \n \n\n \n\n \n\n \n \n1,196,873\n \n\n \nPSU\n \n \n1/3/2025\n \n \n\n \n\n \n\n \n \n7,735\n \n \n \n15,469\n \n \n \n30,938\n \n \n\n \n\n \n\n \n \n1,068,781\n \n\n \nRSU\n \n \n1/3/2025\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n6,629\n \n \n\n \n\n \n \n371,953\n \n\n \n \n\n \nTotal\n \n \n \n\n \n \n\n \n \n\n \n \n217,000\n \n \n \n434,000\n \n \n \n868,000\n \n \n \n7,735\n \n \n \n22,306\n \n \n \n51,449\n \n \n \n6,629\n \n \n \n \n\n \n \n\n \n \n\n \n \n \n\n \n \n\n \n \n\n \n \n2,637,607\n \n\nHarris\n \nAPP\n \n\n \n \n182,000\n \n \n \n364,000\n \n \n \n728,000\n \n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \nEVA\n \n \n12/5/2025\n \n \n\n \n\n \n\n \n \nN/A\n \n \n \n6,837\n \n \n \n20,511\n \n \n\n \n\n \n\n \n \n1,196,873\n \n\n \nPSU\n \n \n1/3/2025\n \n \n\n \n\n \n\n \n \n6,487\n \n \n \n12,974\n \n \n \n25,948\n \n \n\n \n\n \n\n \n \n896,397\n \n\n \nRSU\n \n \n1/3/2025\n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n \n5,560\n \n \n\n \n\n \n \n311,972\n \n\n \n \n\n \nTotal\n \n \n \n\n \n \n\n \n \n\n \n \n182,000\n \n \n \n364,000\n \n \n \n728,000\n \n \n \n6,487\n \n \n \n19,811\n \n \n \n46,459\n \n \n \n5,560\n \n \n \n \n\n \n \n\n \n \n\n \n \n \n\n \n \n\n \n \n\n \n \n2,405,242\n \n\nWetherbee\n \nRSU\n \n \n1/3/2025\n \n \n\n \n\n \n\n \n\n \n\n \n\n \n \n17,822\n \n \n\n \n\n \n \n999,992\n \n\n \n \n\n \nTotal\n \n \n \n\n \n \n\n \n \n\n \n \n \n\n \n \n\n \n \n\n \n \n \n\n \n \n\n \n \n\n \n \n \n\n \n \n\n \n \n\n \n \n \n\n \n \n\n \n \n\n \n \n \n\n \n \n\n \n \n\n \n \n \n\n \n \n\n \n \n\n \n \n17,822\n \n \n \n \n\n \n \n\n \n \n\n \n \n \n\n \n \n\n \n \n\n \n \n999,992\n \n\n \n\n(1)\n\nRepresents the Company’s Annual Performance Plan and Long-Term Incentive Plan, consisting of PSUs and RSUs. Additionally, includes for Ms. Fields, Ms. Bhatia and Mr. Harris, a one-time grant of performance-vested Enterprise Value Acceleration awards, or “EVAs,” for the four-year performance measurement period ending in 2029. The EVA program was designed as a highly performance-contingent, multi-year incentive vehicle intended to award only extraordinary and sustained stock price appreciation. No value will be realized under the program unless significant stock price hurdles are achieved and sustained over time.\n\n \n\n(2)\n\nThe values in this column are based on the aggregate grant date fair value of awards determined in accordance with FASB ASC Topic 718 and correspond to the aggregate values disclosed in the “Stock Awards” column in the Summary Compensation Table.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n64\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nCompensation Discussion and Analysis Outstanding Equity Awards at Fiscal Year-End for 2025\n\n \n\nOUTSTANDING EQUITY AWARDS AT FISCAL YEAR-END FOR 2025\n\n \n\n \n  \n \n \n  \nStock Awards(1)\n \n\nName\n  \nGrant Date\n \n  \nNumber of Shares or Units of\nStock that Have Not Vested\n(#)(2)\n \n \nMarket Value of Shares or Units\nof Stock that Have Not Vested\n($)(3)\n \n  \nEquity Incentive Plan Awards:\nNumber of Unearned Shares,\nUnits or Other Rights That Have\nNot Vested\n(#)\n \n \nEquity Incentive Plan Awards:\nMarket or Payout Value of\nUnearned Shares, Units or\nOther Rights that Have Not\nVested\n($)(3)\n \n\nFields\n  \n \n1/4/2022\n \n  \n \n98,620\n(4) \n \n \n11,317,631\n \n  \n\n \n\n  \n \n1/3/2023\n \n  \n \n6,004\n \n \n \n689,019\n \n  \n\n \n\n  \n \n1/3/2024\n \n  \n \n11,230\n \n \n \n1,288,755\n \n  \n\n \n\n  \n \n1/3/2024\n \n  \n\n \n\n  \n \n39,307\n(5) \n \n \n4,510,871\n \n\n  \n \n7/1/2024\n \n  \n \n13,822\n \n \n \n1,586,213\n \n  \n\n \n\n  \n \n1/3/2025\n \n  \n \n18,713\n \n \n \n2,147,504\n \n  \n\n \n\n  \n \n1/3/2025\n \n  \n\n \n\n  \n \n43,664\n(6) \n \n \n5,010,881\n \n\n \n\n  \n \n12/5/2025\n \n  \n \n \n\n \n \n\n \n \n\n \n \n \n\n \n \n\n \n \n\n  \n \n34,188\n(7) \n \n \n3,923,415\n \n\n \n \n\n  \n \n \n\n \n \n\n \n \n\n  \n \n148,389\n \n \n \n17,029,122\n \n  \n \n117,159\n \n \n \n13,445,167\n \n\nNewman\n  \n \n1/4/2022\n \n  \n \n84,530\n(4) \n \n \n9,700,663\n \n  \n\n \n\n  \n \n1/3/2023\n \n  \n \n4,688\n \n \n \n537,995\n \n  \n\n \n\n  \n \n1/3/2024\n \n  \n \n6,948\n \n \n \n797,352\n \n  \n\n \n\n  \n \n1/3/2024\n \n  \n\n \n\n  \n \n24,321\n(5) \n \n \n2,791,078\n \n\n  \n \n1/3/2025\n \n  \n \n8,300\n \n \n \n952,508\n \n  \n\n \n\n \n\n  \n \n1/3/2025\n \n  \n \n \n\n \n \n\n \n \n\n \n \n \n\n \n \n\n \n \n\n  \n \n19,368\n(6) \n \n \n2,222,672\n \n\n \n \n\n  \n \n \n\n \n \n\n \n \n\n  \n \n104,466\n \n \n \n11,988,518\n \n  \n \n43,689\n \n \n \n5,013,750\n \n\nBhatia\n  \n \n3/20/2024\n \n  \n \n47,627\n \n \n \n5,465,675\n \n  \n\n \n\n  \n \n3/20/2024\n \n  \n\n \n\n  \n \n16,371\n(5) \n \n \n1,878,736\n \n\n  \n \n1/3/2025\n \n  \n \n6,629\n \n \n \n760,744\n \n  \n\n \n\n  \n \n1/3/2025\n \n  \n\n \n\n  \n \n15,469\n(6) \n \n \n1,775,222\n \n\n \n\n  \n \n12/5/2025\n \n  \n \n \n\n \n \n\n \n \n\n \n \n \n\n \n \n\n \n \n\n  \n \n6,837\n(7) \n \n \n784,614\n \n\n \n \n\n  \n \n \n\n \n \n\n \n \n\n  \n \n54,256\n \n \n \n6,226,419\n \n  \n \n38,677\n \n \n \n4,438,572\n \n\nHarris\n  \n \n1/4/2022\n \n  \n \n70,442\n(4) \n \n \n8,083,924\n \n  \n\n \n\n  \n \n1/3/2023\n \n  \n \n3,382\n \n \n \n388,118\n \n  \n\n \n\n  \n \n1/3/2024\n \n  \n \n4,866\n \n \n \n558,422\n \n  \n\n \n\n  \n \n1/3/2024\n \n  \n\n \n\n  \n \n17,033\n(5) \n \n \n1,954,707\n \n\n  \n \n1/3/2025\n \n  \n \n5,560\n \n \n \n638,066\n \n  \n\n \n\n  \n \n1/3/2025\n \n  \n\n \n\n  \n \n12,974\n(6) \n \n \n1,488,896\n \n\n \n\n  \n \n12/5/2025\n \n  \n \n \n\n \n \n\n \n \n\n \n \n \n\n \n \n\n \n \n\n  \n \n6,837\n(7) \n \n \n784,614\n \n\n \n \n\n  \n \n \n\n \n \n\n \n \n\n  \n \n84,250\n \n \n \n9,668,530\n \n  \n \n36,844\n \n \n \n4,228,217\n \n\nWetherbee\n  \n \n1/4/2022\n \n  \n \n176,106\n(4) \n \n \n20,209,925\n \n  \n\n \n\n \n\n  \n \n1/3/2023\n \n  \n \n13,531\n \n \n \n1,552,818\n \n  \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n  \n \n1/3/2024\n \n  \n \n18,717\n \n \n \n2,147,963\n \n  \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n  \n \n1/3/2024\n \n  \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n  \n \n65,512\n(5) \n \n \n7,518,157\n \n\n \n\n  \n \n1/3/2025\n \n  \n \n17,822\n \n \n \n2,045,253\n \n  \n \n \n\n \n \n\n \n \n\n \n \n \n\n \n \n\n \n \n\n \n \n\n  \n \n \n\n \n \n\n \n \n\n  \n \n226,176\n \n \n \n25,955,959\n \n  \n \n65,512\n \n \n \n7,518,157\n \n\n \n\n(1)\n\nThis table relates to awards under the current LTIP, including (a) time-vested RSUs granted in 2023, 2024 and 2025, which vest ratably in one-third increments over a three-year period, (b) performance-vested awards, or PSUs, for the three-year performance measurement periods ending in 2026 and 2027, and (c) for Ms. Fields, Ms. Bhatia and Mr. Harris, a one-time grant of performance-vested EVAs for the four-year performance measurement period ending in 2029. The EVA program was designed as a highly performance-contingent, multi-year incentive vehicle intended to award only extraordinary and sustained stock price appreciation. No value will be realized under the program unless significant stock price hurdles are achieved and sustained over time. Additionally, this table includes the remaining unvested portion of the one-time performance-vested Breakout Performance Plan awards, or “BPUs,” granted in 2022 to Ms. Fields and Messrs. Newman, Harris and Wetherbee for the four-year measurement period ending in 2025. One-half of these BPU awards was paid in early 2026; the remaining half will be paid in early 2027, subject to the recipient’s ongoing employment by the Company (or qualifying death, disability or retirement) and are therefore reflected on the table as time-vested awards. PSUs for the performance period ended December 31, 2025, were settled during the first quarter of 2026 but vested as of December 31, 2025, and, therefore, are not shown as outstanding on this table on this table.\n\n \n\n(2)\n\nThe number of shares reported in this column represents the number of shares payable pursuant to the time-vested RSUs granted in 2023, 2024 and 2025 and for Ms. Fields and Messrs. Newman, Harris and Wetherbee, the remaining portion of the 2022 BPU awards that will be in early paid 2027.\n\n \n\n(3)\n\nAmounts were calculated using $114.76 per share, the closing price of ATI common stock at December 31, 2025.\n\n \n\n(4)\n\nConsists of BPU awards granted in 2022, as described above in footnote 1.\n\n \n\n(5)\n\nConsists of target PSUs granted under the LTIP in 2024. The number of shares reported represents the number of shares that would be awarded if all applicable performance measures under the 2024 PSU grants are met at the end of the applicable three-year performance measurement period.\n\n \n\n(6)\n\nConsists of target PSUs granted under the LTIP in 2025. The number of shares reported represents the number of shares that would be awarded if all applicable performance measures under the 2025 PSU grants are met at the end of the applicable three-year performance measurement period.\n\n \n\n(7)\n\nConsists of target EVAs granted under the LTIP in 2025. The number of shares reported represents the number of shares that would be awarded if all applicable performance measures under the 2025 EVA grants are met at the end of the applicable four-year performance measurement period.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nCompensation Discussion and Analysis Option Exercises and Stock Vested for 2025\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n65 \n\n \n\nThe Company does not issue stock option awards or stock appreciation rights and has not issued stock options or stock appreciation rights to its employees since 2003. The Company does not anticipate that it will use stock options or stock appreciation rights as part of its compensation program going forward. The Company does not have any program, plan, or practice to time annual or ad hoc grants of equity-based awards in coordination with the release of material non-public information or otherwise, and does not grant stock options or stock appreciation rights during periods in which there is material nonpublic information about the Company.\n\nOPTION EXERCISES AND STOCK VESTED FOR 2025\n\n \n\n \n  \nStock Awards\n \n\nName\n  \nNumber of Shares\nAcquired on Vesting\n(#)(1)\n \n  \nValue Realized on\nVesting\n($)(2)\n \n\nFields\n  \n \n205,603\n \n  \n \n23,289,410\n \n\nNewman\n  \n \n167,407\n \n  \n \n19,059,661\n \n\nBhatia\n  \n \n10,829\n \n  \n \n572,091\n \n\nHarris\n  \n \n130,065\n \n  \n \n14,886,457\n \n\nWetherbee\n  \n \n416,142\n \n  \n \n46,840,213\n \n\n \n\n(1)\n\nConsists of: (a) 82,216 shares, 64,197 shares, 46,318 shares and 185,276 shares awarded to Ms. Fields and Messrs. Newman, Harris and Wetherbee, respectively, pursuant to their 2023 PSU awards, based on payout at 195.6% of their respective target awards; (b) 98,620 shares, 84,530 shares, 70,442 shares and 176,106 shares awarded to Ms. Fields and Messrs. Newman, Harris and Wetherbee, respectively, pursuant to their 2022 Breakout Plan awards, half of which vested as of December 31, 2025, based on maximum payout of their respective target awards, (c) 13,146 shares, 10,516 shares, 7,489 shares and 31,869 shares awarded to Ms. Fields and Messrs. Newman, Harris and Wetherbee, respectively, on the third anniversary of the grant date for the RSUs granted to each of them in 2022, (d) 6,005 shares, 4,689 shares, 3,383 shares and 13,532 shares awarded to Ms. Fields and Messrs. Newman, Harris and Wetherbee, respectively, on the second anniversary of the grant date for the RSUs granted to each of them in 2023; (e) 5,616 shares, 3,475 shares, 1,913 shares, 2,433 shares and 9,359 shares awarded to Ms. Fields, Mr. Newman, Ms. Bhatia, and Messrs. Harris and Wetherbee, respectively, on the first anniversary of the grant date for the RSUs granted to each of them in 2024; and (f) 8,916 shares awarded to Ms. Bhatia upon vesting of a portion of the RSUs granted to her in 2024 when she joined the Company.\n\n \n\n(2)\n\nAmounts were calculated using: (a) for the 2022 RSUs, $56.63 per share, which was the average of the high and low trading prices for the Company’s stock on the NYSE on January 6, 2025; (b) for the 2023 and 2024 RSUs, $55.81 per share, which was the average of the high and low trading prices for the Company’s stock on the NYSE on January 3, 2025; and (c) for the 2023-2025 PSUs and the Breakout Plan awards, $121.09 per share, which was the average of the high and low trading prices for the Company’s stock on the NYSE on January 5, 2026.\n\nThe Company does not issue stock option awards and has not issued stock options to its employees since 2003.\n\nPENSION BENEFITS FOR 2025\n\n \n\nName(1)\n  \nPlan Name\n  \nYears of\nCredited\nService\n(#)(2)\n \n  \nPresent\nValue of\nAccumulated\nBenefit\n($)\n \n  \nPayments\nDuring Last\nFiscal Year\n($)\n \n\nFields\n  \nN/A\n  \n \n—\n \n  \n \n—\n \n  \n \n—\n \n\nNewman\n  \nN/A\n  \n \n—\n \n  \n \n—\n \n  \n \n—\n \n\nBhatia\n  \nN/A\n  \n \n—\n \n  \n \n—\n \n  \n \n—\n \n\nHarris\n  \nN/A\n  \n \n—\n \n  \n \n—\n \n  \n \n—\n \n\nWetherbee\n  \nATI Pension Plan 2\n  \n \n—\n \n  \n \n—\n \n  \n \n—\n \n\n \n  \nATI Non-Qualified Benefit Restoration Plan\n  \n \n3\n \n  \n \n158,239\n \n  \n \n—\n \n\n \n\n(1)\n\nMs. Fields, Ms. Bhatia and Messrs. Newman and Harris do not participate in any defined benefit plans.\n\n \n\n(2)\n\nYears of credited service reflect the number of years of service used for determining benefits for Mr. Wetherbee during his participation under the respective plans.\n\n \n\n(3)\n\nATI Pension Plan 2, in which Mr. Wetherbee participated, was terminated effective December 31, 2022. In connection with the termination, Mr. Wetherbee elected to receive a lump sum benefit that was paid to him in 2023. See “Pension Benefits” on page 66 of this Proxy Statement for more information.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n66\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nCompensation Discussion and Analysis Non-Qualified Deferred Compensation for 2025\n\n \n\nPlan\n  \nBenefit Formulas and Retirement Information\n\nATI Pension Plan\n\nQualified defined benefit plan\n\n \n\nThe Allegheny Technologies Incorporated Pension Plan (“ATI Pension Plan”) is the result of the mergers of several plans previously sponsored by:\n\n \n\n◆\n\nAllegheny Ludlum\nCorporation (“Allegheny Ludlum”), and\n\n \n\n◆\n\nTeledyne Inc. (“TDY”)\n\n \n\nEffective December 31, 2014, the Company froze future benefit accruals under the ATI Pension Plan for all participating employees other than those with collectively-bargained employment arrangements.\n\n  \n\nThe ATI Pension Plan has a number of benefit formulas that apply separately to various groups of employees and retirees, generally, by work location and job classification. A principal determinant of which formula applied prior to December 31, 2014 (the date at which the Company froze all remaining future benefit accruals) is whether the employee was employed by TDY at the time the respective companies became members of the controlled group that includes the Company.\n\n \n\nAllegheny Ludlum ceased pension accruals under its pension formula in 1988, except for employees who then met certain age and service criteria, which subsequently were frozen on December 31, 2014.\n\n \n\nEach formula for Allegheny Ludlum and TDY multiplies years of service by compensation and then by a factor to produce a benefit amount payable as a straight life annuity. That benefit amount is reduced with respect to Social Security amounts payable to determine the annuity amount payable. Participants can choose alternate benefit forms, including survivor benefits. The Allegheny Ludlum and TDY definitions of service and compensation differ somewhat, as do the factors used in the respective formulas.\n\nATI Pension Plan 2\n\nQualified defined benefit plan\n\n \n\nThe ATI Pension Plan 2 was a qualified defined benefit plan to which certain former participants in the ATI Pension Plan were transferred.\n\n  \nAs part of the Company’s ongoing pension liability management efforts, certain employees who participated in the ATI Pension Plan but were no longer accruing benefits thereunder were transferred, most recently as of December 31, 2021, to a new qualified defined benefit plan, the ATI Pension Plan 2, with terms and conditions substantially the same as the ATI Pension Plan. Consequently, Mr. Wetherbee’s pension benefit was included in the ATI Pension Plan 2. His pension benefit formula includes a period of service with TDY. The ATI Pension Plan 2 was terminated effective December 31, 2022, and its assets liquidated during 2023, in connection with which, Mr. Wetherbee elected to receive a lump sum benefit.\n\nATI Benefit Restoration Plan\n\nNon-Qualified benefit plan\n\n \n\nEffective December 31, 2014, the Company froze future benefit accruals under the defined benefit portion of the ATI Benefit Restoration Plan, in which Mr. Wetherbee participated.\n\n  \n\nUnder the non-qualified ATI Benefit Restoration Plan, the Company accrues benefits for the NEOs that restore to eligible NEOs the amounts that cannot be paid to them under the terms of the Company’s defined contribution plans or the defined benefit plan (the ATI Pension Plan), in either case due to the limitations set forth in the Code. All NEOs are eligible to participate in the ATI Benefit Restoration Plan to the extent of benefits that cannot be accrued under the defined contribution plan in which the NEO participates.\n\n \n\nDistributions under the ATI Benefit Restoration Plan are available only at the times and in the same forms as under the ATI Pension Plan, subject to payment delays to comply with Section 409A of the Code.\n\nNON-QUALIFIED DEFERRED COMPENSATION FOR 2025\n\n \n\nName\n  \nRegistrant\nContributions\nIn Last FY\n($)(1)\n \n    \nAggregate\nEarnings\nIn Last FY\n($)(2)\n \n    \nAggregate\nWithdrawals/\nDistributions\n($)\n \n    \nAggregate\nBalance\nat Last FYE\n($)\n \n\nFields\n  \n \n161,784\n \n    \n \n16,429\n \n    \n \n—\n \n    \n \n622,967\n \n\nNewman\n  \n \n89,384\n \n    \n \n10,700\n \n    \n \n—\n \n    \n \n404,369\n \n\nBhatia\n  \n \n49,400\n \n    \n \n867\n \n    \n \n—\n \n    \n \n54,890\n \n\nHarris\n  \n \n55,718\n \n    \n \n7,305\n \n    \n \n—\n \n    \n \n276,669\n \n\nWetherbee\n  \n \n134,077\n \n    \n \n36,697\n \n    \n \n—\n \n    \n \n1,309,239\n \n\n \n\n(1)\n\nReflects contributions made pursuant to the non-qualified defined contribution portion of the ATI Non-Qualified Benefit Restoration Plan. Under the terms of the plan, the participants do not contribute; only the Company contributes to the plan on the participants’ behalf. These amounts are included in the “All Other Compensation” column of the Summary Compensation Table for 2025.\n\n \n\n(2)\n\nAggregate earnings for the ATI Non-Qualified Benefit Restoration Plan are calculated on a daily basis, including current year contributions, multiplied by the interest rate on the Fixed Income Fund investment option in the Company’s qualified defined contribution plan.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nCompensation Discussion and Analysis Employment and Change in Control Agreements\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n67 \n\n \n\nEMPLOYMENT AND CHANGE IN CONTROL AGREEMENTS\n\nEmployment Agreements\n\nATI does not have any employment agreements with its NEOs.\n\nChange in Control Agreements\n\nThe Company has agreements with each currently-employed NEO and certain other key employees to encourage the continued support of the executive and the availability of the executive’s advice and counsel notwithstanding the possibility, threat or occurrence of a change in control. All of our executive officers and certain other key members of the Company’s leadership have change in control agreements, none of which include any excise tax gross-up provision.\n\n \n\n \n\n \n\n \n\nUnder the agreements, a “change in control” is defined as:\n\n \n\n◆\n\nan acquisition by any individual, entity or group (a “Person”) of beneficial ownership of 20% or more of either (1) the then outstanding shares of common stock of the Company or (2) the combined voting power of the then outstanding voting securities of the Company entitled to vote generally in the election of directors;\n\n \n\n◆\n\nthe completion of a tender offer pursuant to which 20% or more of the voting power of Company stock has been acquired, subject to limited exceptions;\n\n \n\n◆\n\na change in the composition of the Board such that the individuals who constitute the Board cease for any reason to constitute at least a majority of the Board, subject to limited exceptions for directors who are appointed or nominated by the incumbent Board;\n\n \n\n◆\n\nthe occurrence of a successful solicitation electing or removing 50% of the members of the Board or the Board consisting less than 51% of continuing directors;\n\n \n\n◆\n\nthe occurrence of a merger, consolidation, sale or similar business combination transaction, unless:\n\n \n\n–\n\nthe existing beneficial owners of the Company’s outstanding stock immediately prior to the transaction continue to hold more than 50% of the equity and voting power of the resulting entity;\n\n \n\n–\n\nno person beneficially owns 20% or more of the outstanding equity of the resulting entity, except to the extent that such ownership existed prior to the transaction; and\n\n \n\n–\n\nat least a majority of the members of the board of directors (or, for a noncorporate entity, equivalent body or committee) of the entity resulting from such transaction were members of the Incumbent Board at the time of the execution of the initial agreement, or of the action of the Board, providing for such transaction; or\n\n \n\n–\n\napproval by the shareholders of the Company of a complete liquidation or dissolution of the Company.\n\n \n\n \n\n \n\nIn general, the agreements provide for the payment of severance benefits if a change in control occurs and, within 24 months after the change in control, either:\n\n \n\n◆\n \n\nthe Company terminates the executive’s employment without “cause,” which is defined to mean a felony conviction or plea of guilty to a charge of commission of a felony, breach of fiduciary duty owed to the Company involving personal profit, willful engaging by the executive in gross misconduct that is materially and demonstrably injurious to the Company, or intentional continued failure to perform stated duties after 30 days’ notice to cure; or\n\n \n\n \n \n\n \n\nthe executive terminates employment with the Company for “good reason,” which is defined to mean:\n\n \n\n◆\n\na material diminution of duties, responsibilities or status or the assignment of duties inconsistent with position;\n\n \n\n◆\n\nrelocation more than 35 miles from principal job location;\n\n \n\n◆\n\nreduction in annual salary or material reduction in other compensation or benefits;\n\n \n\n◆\n\nfailure by the Company to cause a successor to assume and agree to perform the Company’s obligations under the agreement;\n\n \n\n◆\n\nmaterial diminution in the budget over which the executive retains authority; or\n\n \n\n◆\n\npurported termination other than as expressly permitted in the agreement.\n\n \n\n \n \n\nAn executive officer entitled to severance benefits under a change in control agreement will be paid a lump sum cash payment generally within thirty days of the date of termination (except to the extent of compensation that is deemed to be “deferred compensation” under Section 409A of the Internal Revenue Code) equal to the sum of:\n\n \n\n◆\n \n\nbase severance consisting of base salary (based on the highest annual rate of base salary of the executive as in effect within two years prior to either his or her termination or the effective date of the change in control) plus annual cash incentive (at the greater of target for the year in which the change in control occurs or the actual amount paid for the year prior to the year in which the change in control occurs) times a multiple (which is 2.99x for Mr. Wetherbee and Ms. Fields and 2x for Ms. Bhatia and Messrs. Newman and Harris);\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n68\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nCompensation Discussion and Analysis Employment and Change in Control Agreements\n\n \n\n◆\n \n\naggregate amounts accrued through the date of termination (including but not limited to accrued but unpaid salary or cash incentive compensation and amounts accrued under any qualified, non-qualified or supplemental employee benefit plan); and\n\n \n\n◆\n \n\nprorated annual incentive for the then uncompleted year measured at the greater of target or the level of performance achieved through the date of termination projected through the end of the year.\n\nThe executive will also be provided:\n\n \n\n◆\n \n\nan additional lump sum payment equal to the incremental cost to the executive to maintain continued health and welfare coverage for the executive and, if applicable, his or her eligible dependents, under the Company’s group health plan(s) for a period of 36 months;\n\n \n\n◆\n \n\nreimbursement for outplacement services up to $25,000 for Ms. Fields and Mr. Wetherbee and $15,000 for Ms. Bhatia and Messrs. Newman and Harris; and\n\n \n\n◆\n \n\nfor Mr. Wetherbee, credited service and full vesting under certain legacy supplemental pension plans in which he participates (and which were closed to new participants prior to the time that Mses. Fields and Bhatia or Messrs. Newman and Harris joined the Company).\n\nThe agreements have a term of three years, which three-year term will continue to be extended until either party gives written notice that it no longer wants to continue to extend the term. If a change in control occurs during the term, the agreements will remain in effect for the longer of three years or until all obligations of the Company under the agreements have been fulfilled.\n\nThe Compensation and Leadership Development Committee has reviewed the change in control valuation, as well as the purposes and effects of the agreements, and determined that it is in the Company’s best interests to retain the change in control agreements on their terms and conditions.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nCompensation Discussion and Analysis Potential Payments Upon Termination\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n69 \n\n \n\nPOTENTIAL PAYMENTS UPON TERMINATION\n\nThe tables below reflect estimates of the amount of compensation (in addition to the amounts shown in the compensation tables) payable to each NEO in the event of termination of such executive’s employment by reason of retirement, death or disability, or within 24 months following a change in control to the extent such termination is without cause or is the result of the executive’s resignation for good reason. The amounts shown assume that such termination was effective as of December 31, 2025. The closing price of ATI’s common stock on the NYSE on that date was $114.76. The amounts shown are estimates of the amounts that would be paid out to the executives upon their termination under the circumstances specified. For purposes of the tables, calculations related to incentive compensation are based on the greater of the target award or the value earned for actual performance against the preset performance goals through the assumed date of termination. The actual amounts payable can only be determined at the time of such executive’s separation from the Company.\n\nPayments Made Upon Termination\n\nRegardless of the manner in which a NEO’s employment terminates, he or she may be entitled to receive amounts earned during his or her term of employment. Such amounts include:\n\n \n\n◆\n \n\nnon-equity incentive compensation earned during the fiscal year;\n\n \n\n◆\n \n\namounts contributed under the savings portion of the defined contribution plan and the Benefit Restoration Plan;\n\n \n\n◆\n \n\nunused vacation pay; and\n\n \n\n◆\n \n\namounts accrued and vested through the ATI Pension Plan.\n\nPayments Made Upon Retirement\n\nIn the event of the retirement of a NEO, in addition to the items identified above, he or she will be entitled (subject to the Company’s consent for certain amounts) to receive his or her outstanding equity awards (or a prorated portion thereof) when the shares subject to such awards would otherwise have become payable as a result of the passage of time or the achievement of the applicable performance criteria.\n\nConsent of the Company is required for payments of awards under the long-term compensation plans upon retirement.\n\nPayments Made Upon Death or Disability\n\nIn the event of the death or disability of a NEO, in addition to the benefits listed under the headings “Payments Made Upon Termination” above, the NEO or their estate will be entitled to receive his or her outstanding equity awards and may receive benefits under the Company’s disability plan or payments under the Company’s life insurance plan, as appropriate, each as generally available to all salaried employees.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n70\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nCompensation Discussion and Analysis Potential Payments Upon Termination\n\n \n\nPayments Made Upon a Change in Control\n\nThe Company is a party to a change in control severance agreement with each NEO that provides the NEO with payments in the event his or her employment is terminated by the Company for reasons other than cause or by the NEO for good reason (defined to include changes such as diminishment of pay, benefits, title or job responsibilities or transfer from the home office) within 24 months after a change in control. See the information under the caption “Employment and Change in Control Agreements” for definitions.\n\nThe tables below illustrate the amount of payments due in various circumstances, including following a change in control. As noted, the column “Involuntary Not for Cause Termination or Good Reason Termination by Executive (w/in 24 Months of a Change in Control)” assumes that there was a change in control at the December 31, 2025, closing price of $114.76 per share, and all of the NEOs had a triggering event on December 31, 2025, and all cash amounts due, all deferred compensation enhancements, and all potential benefit payments were to be paid in a single lump sum.\n\n \n\n \n\n \n\nKimberly A. Fields ($ in thousands):\n\n \n\n \n\n \n\n \n\n \n \n\n \n \nExecutive Benefit and Payments\nUpon Separation\n  \nRetirement\n \n  \nInvoluntary Not for Cause\nTermination or Good Reason\nTermination by Executive\n(w/in 24 months of Change\nin Control)\n \n    \nDisability\n \n    \nDeath\n \n \n \n\n \n\n \n\n \n \n\n \n\n \nBase Severance(1):\n  \n \n0\n \n  \n \n7,093\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \nShort-Term Incentive Compensation:\n  \n\n \n\n \n\n \n\n  \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n \n\n \n\n \n Accrued 2025 APP\n  \n \n2,296\n \n  \n \n2,296\n \n    \n \n2,296\n \n    \n \n2,296\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \nLong-Term Incentive Compensation:\n  \n\n \n\n \n\n \n\n  \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n \n\n \n\n \n LTIP(2)\n  \n \n17,029\n \n  \n \n17,029\n \n    \n \n17,029\n \n    \n \n17,029\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \nOther Benefits:\n  \n\n \n\n \n\n \n\n  \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n \n\n \n\n \n Non-qualified defined contribution plan\n  \n \n0\n \n  \n \n227\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \n Non-qualified defined benefit plan\n  \n \n0\n \n  \n \n0\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \n Health & Welfare Benefits\n  \n \n0\n \n  \n \n60\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \n Outplacement\n  \n \n0\n \n  \n \n25\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \nTotal\n  \n \n19,325\n \n  \n \n26,730\n \n    \n \n19,325\n \n    \n \n19,325\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \n\n(1) Includes the sum of Ms. Fields’ base salary rate at December 31, 2025, of $950,000 and $1,422,302 (her actual award under the 2024 APP), times her 2.99x multiple.\n\n \n\n(2)  Amounts shown for termination as a result of retirement, disability or death exclude the results of the 2023 – 2025 PSUs that vested at a rate of 195.6% of target on December 31, 2025, the first installment paid with respect to the 2022 – 2025 BPUs that vested at their maximum level on December 31, 2025, and the pro-rata portion of PSU awards, including under the EVA program, that may become payable at a future date based on the Company’s actual performance relative to applicable targets.\n\n \n\n  \n\n   \n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nCompensation Discussion and Analysis Potential Payments Upon Termination\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n71 \n\n \n\n \n \n\n \n\nDonald P. Newman ($ in thousands):\n\n \n\n \n \n\n \n\n \n\n \n \n\n \n \n\n \nExecutive Benefit and Payments\nUpon Separation\n  \nRetirement\n \n  \nInvoluntary Not for Cause\nTermination or Good Reason\nTermination by Executive\n(w/in 24 months of Change\nin Control)\n \n    \nDisability\n \n    \nDeath\n \n \n \n \n\n \n\n \n\n \n \n\n \n\n \nBase Severance(1):\n  \n \n0\n \n  \n \n2,935\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \nShort-Term Incentive Compensation:\n  \n\n \n\n \n\n \n\n  \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n \n\n \n\n \n Accrued 2025 APP\n  \n \n1,044\n \n  \n \n1,044\n \n    \n \n1,044\n \n    \n \n1,044\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \nLong-Term Incentive Compensation:\n  \n\n \n\n \n\n \n\n  \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n \n\n \n\n \n LTIP(2)\n  \n \n11,988\n \n  \n \n11,988\n \n    \n \n11,988\n \n    \n \n11,988\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \nOther Benefits:\n  \n\n \n\n \n\n \n\n  \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n \n\n \n\n \n Non-qualified defined contribution plan\n  \n \n0\n \n  \n \n108\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \n Non-qualified defined benefit plan\n  \n \n0\n \n  \n \n0\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \n Health & Welfare Benefits\n  \n \n0\n \n  \n \n56\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \n Outplacement\n  \n \n0\n \n  \n \n15\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \nTotal\n  \n \n13,032\n \n  \n \n16,146\n \n    \n \n13,032\n \n    \n \n13,032\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \n\n(1) Includes the sum of Mr. Newman’s base salary rate at December 31, 2025, of $675,000 and $792,303 (his actual award under the 2024 APP), times his 2x multiple.\n\n \n\n(2)  Amounts shown for termination as a result of retirement, disability or death exclude the results of the 2023 – 2025 PSUs that vested at a rate of 195.6% of target on December 31, 2025, the first installment paid with respect to the 2022 – 2025 BPUs that vested at their maximum level on December 31, 2025, and the pro-rata portion of PSU awards, that may become payable at a future date based on the Company’s actual performance relative to applicable targets.\n\n \n\n  \n\n   \n\n \n\n \n\n \n \n\n \n\nVaishali S. Bhatia ($ in thousands):\n\n \n\n \n \n\n \n\n \n\n \n \n\n \nExecutive Benefit and Payments\nUpon Separation(1)\n  \nInvoluntary Not for Cause\nTermination or Good Reason\nTermination by Executive\n(w/in 24 months of Change\nin Control)\n \n    \nDisability\n \n    \nDeath\n \n \n \n \n\n \n\n \n\n \n\n \nBase Severance(2):\n  \n \n2,168\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n\n \nShort-Term Incentive Compensation:\n  \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n Accrued 2025 APP\n  \n \n827\n \n    \n \n827\n \n    \n \n827\n \n \n\n \n\n \n\n \n\n \n\n \nLong-Term Incentive Compensation:\n  \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n LTIP(3)\n  \n \n6,226\n \n    \n \n6,226\n \n    \n \n6,226\n \n \n\n \n\n \n\n \n\n \n\n \nOther Benefits:\n  \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n Non-qualified defined contribution plan\n  \n \n99\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n\n \n Non-qualified defined benefit plan\n  \n \n0\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n\n \n Health & Welfare Benefits\n  \n \n55\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n\n \n Outplacement\n  \n \n15\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n\n \nTotal\n  \n \n9,390\n \n    \n \n7,053\n \n    \n \n7,053\n \n \n\n \n\n \n\n \n\n \n\n \n\n(1) Ms. Bhatia was not yet retirement eligible as of December 31, 2025. Therefore, no amounts with respect to retirement are shown.\n\n \n\n(2)  Includes the sum of Ms. Bhatia’s base salary rate at December 31, 2025, of $620,000 and $464,235 (her actual award under the 2024 APP), times her 2x multiple.\n\n \n\n(3)  Amounts shown for termination as a result of retirement, disability or death exclude the pro-rata portion of remaining PSU awards, including under the EVA program, that may become payable at a future date based on the Company’s actual performance relative to applicable targets.\n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n72\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nCompensation Discussion and Analysis Potential Payments Upon Termination\n\n \n\n \n \n\n \n\nTimothy J. Harris ($ in thousands):\n\n \n\n \n \n\n \n\n \n\n \n \n\n \nExecutive Benefit and Payments\nUpon Separation(1)\n  \nInvoluntary Not for Cause\nTermination or Good Reason\nTermination by Executive\n(w/in 24 months of Change\nin Control)\n \n    \nDisability\n \n    \nDeath\n \n \n \n \n\n \n\n \n\n \n\n \nBase Severance(2):\n  \n \n2,093\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n\n \nShort-Term Incentive Compensation:\n  \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n Accrued 2025 APP\n  \n \n708\n \n    \n \n708\n \n    \n \n708\n \n \n\n \n\n \n\n \n\n \n\n \nLong-Term Incentive Compensation:\n  \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n LTIP(3)\n  \n \n9,669\n \n    \n \n9,669\n \n    \n \n9,669\n \n \n\n \n\n \n\n \n\n \n\n \nOther Benefits:\n  \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n Non-qualified defined contribution plan\n  \n \n83\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n\n \n Non-qualified defined benefit plan\n  \n \n0\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n\n \n Health & Welfare Benefits\n  \n \n54\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n\n \n Outplacement\n  \n \n15\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n\n \nTotal\n  \n \n12,622\n \n    \n \n10,377\n \n    \n \n10,377\n \n \n\n \n\n \n\n \n\n \n\n \n\n(1) Mr. Harris was not yet retirement eligible as of December 31, 2025. Therefore, no amounts with respect to retirement are shown.\n\n \n\n(2)  Includes the sum of Mr. Harris’s base salary rate at December 31, 2025, of $520,000 and $526,474 (his actual award under the 2024 APP), times his 2x multiple.\n\n \n\n(3)  Amounts shown for termination as a result of retirement, disability or death exclude the results of the 2023 – 2025 PSUs that vested at a rate of 195.6% of target on December 31, 2025, the first installment paid with respect to the 2022 – 2025 BPUs that vested at their maximum level on December 31, 2025, and the pro-rata portion of PSU awards, including under the EVA program, that may become payable at a future date based on the Company’s actual performance relative to applicable targets.\n\n \n\n \n\n \n \n\n \n\nRobert S. Wetherbee ($ in thousands):\n\n \n\n \n \n\n \n\n \n\n \n \n\n \n \n\n \nExecutive Benefit and Payments\nUpon Separation\n  \nRetirement\n \n  \nInvoluntary Not for Cause\nTermination or Good Reason\nTermination by Executive\n(w/in 24 months of Change\nin Control)\n \n    \nDisability\n \n    \nDeath\n \n \n \n \n\n \n\n \n\n \n \n\n \n\n \nBase Severance(1):\n  \n \n0\n \n  \n \n7,638\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \nShort-Term Incentive Compensation:\n  \n\n \n\n \n\n \n\n  \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n \n\n \n\n \n Accrued 2025 Short-Term Incentive\n  \n \n500\n \n  \n \n500\n \n    \n \n500\n \n    \n \n500\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \nLong-Term Incentive Compensation:\n  \n\n \n\n \n\n \n\n  \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n \n\n \n\n \n LTIP(2)\n  \n \n25,956\n \n  \n \n25,956\n \n    \n \n25,956\n \n    \n \n25,956\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \nOther Benefits:\n  \n\n \n\n \n\n \n\n  \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n    \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n\n \n \n\n \n\n \n Non-qualified defined contribution plan\n  \n \n0\n \n  \n \n120\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \n Non-qualified defined benefit plan\n  \n \n0\n \n  \n \n0\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \n Health & Welfare Benefits\n  \n \n0\n \n  \n \n54\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \n Outplacement\n  \n \n0\n \n  \n \n25\n \n    \n \n0\n \n    \n \n0\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \nTotal\n  \n \n26,456\n \n  \n \n26,293\n \n    \n \n26,456\n \n    \n \n26,456\n \n \n\n \n\n \n\n \n\n \n \n\n \n\n \n\n(1) Includes the sum of $1,040,000 (the highest annual rate of base salary paid to Mr. Wetherbee within the two year prior to the assumed change in control) and $1,514,420 (his actual award under the 2024 APP), times his 2.99x multiple.\n\n \n\n(2)  Amounts shown for termination as a result of retirement, disability or death exclude the results of the 2023 – 2025 PSUs that vested at a rate of 195.6% of target on December 31, 2025, the first installment paid with respect to the 2022 – 2025 BPUs that vested at their maximum level on December 31, 2025, and the pro-rata portion of PSU awards that may become payable at a future date based on the Company’s actual performance relative to applicable targets.\n\n \n\n  \n\n   \n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nCEO Pay Ratio\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n73 \n\n \n\nCEO PAY RATIO\n\n \n\nFor 2025, our last completed fiscal year, the ratio of the annual total compensation of our CEO to the annual total compensation of our median employee was 123:1. This ratio is a reasonable estimate calculated in a manner consistent with Item 402(u) of Regulation S-K.\n\n \n\nWe believe the methodology, assumptions and estimates described below to be reasonable given our employee population. The SEC rules grant companies significant flexibility in determining the methodology, assumptions and estimates used to comply with the requirements of this disclosure. As acknowledged by the SEC, this flexibility could reduce the comparability of disclosed pay ratios across companies. Therefore, our pay ratio may not necessarily be representative of or comparable to pay ratios disclosed by other companies in the industry or otherwise. Further, the Committee remains mindful of internal pay equity and the importance of responsible executive compensation governance. ATI maintains broad-based compensation programs for employees across the organization and regularly reviews market competitiveness and internal alignment in setting executive compensation.\n\n \n\nTo identify our median employee and to calculate the annual total compensation of our median employee and that of our CEO, we used the following methodology, assumptions and estimates:\n\n \n\nSelection of Determination\nDate\n \nWe selected December 31, 2025, as the date on which we would identify the median employee from our adjusted employee population for 2025.\n\nDetermination\nof Adjusted\nEmployee\nPopulation\n \n\nAs of December 31, 2025, we had a total of 7,572 U.S. and non-U.S. employees. To establish the population for identifying our median employee, we excluded 227 employees who were on either leave or suspended status, as well as 55 employees located in a number of foreign jurisdictions under the 5% de minimis exception as shown in the table below.\n\n \n\nOur remaining employee population as of December 31, 2025 consisted of approximately 7,290 employees working either full time or part time in the United States, Poland or China at our parent company and consolidated subsidiaries, including our majority-owned joint venture, STAL.\n\n \n\nJurisdictions Excluded from Employee Population\n\n(number of employees estimated as of December 31, 2025)\n\n \n\n \n\n \n\n \n\nHeadcount at December 31, 2025 By Region\n\n \n\n \n\n United Kingdom\n\n \n\n  \n \n \n\n11 \n \n\n \n\n \n\n India\n\n \n\n  \n \n \n\n5 \n \n\n \n\n \n  \n \n\n \n\n Germany\n\n \n\n  \n \n \n\n6 \n \n\n \n\n \n\n Singapore\n\n \n\n  \n \n \n\n3 \n \n\n \n\n \n\n France\n\n \n\n  \n \n \n\n10 \n \n\n \n\n \n\n Taiwan\n\n \n\n  \n \n \n\n2 \n \n\n \n\n \n\n Japan\n\n \n\n  \n \n \n\n8 \n \n\n \n \n\n \n\n Spain\n\n \n\n  \n \n \n\n2 \n \n\n \n\n \n\n Korea\n\n \n\n  \n \n \n\n6 \n \n\n \n\n \n\n Italy & Brazil (each)\n\n \n\n  \n \n \n\n1 \n \n\n \n \n\n \n\n  \n\n \n\n  \n\n \n\n  \n\n \n\n  \n\n \n\n \n\n \n\n \n \n\nIdentification\nof Median\nEmployee\n \n\nWe compared the cash compensation, including wages, overtime, salary and bonuses, paid during our fiscal year 2025 for each employee who was included in our adjusted employee population as the consistently applied compensation measure used to identify the median employee among those included in the adjusted employee population.\n\n \n\n◆\n\nAs part of this analysis, we converted the compensation paid to non-U.S. employees from local currency to U.S. dollars using exchange rates in effect on December 31, 2025; and\n\n \n\n◆\n\nannualized the compensation of each full-time or part-time employee who was hired in 2025 and included in the adjusted employee population.\n\nCalculation of\nAnnual Total Compensation\n \n\n◆\n\nWe determined the median employee’s 2025 annual total compensation to be $109,510, which is the amount that would have been reported for our median employee in the “Total” column of our 2025 Summary Compensation Table if he had been a Named Executive Officer for fiscal 2025.\n\n \n\n◆\n\nWe determined the CEO’s 2025 annual total compensation to be $13,512,737. We used the amount reported for Ms. Fields in the “Total” column* of our 2025 Summary Compensation Table.\n\n \n\n*See Summary Compensation Table “Total” column (j) on page 61 of this proxy statement.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n74\n\n \n \n \n\n \n\nATI\n\n 2026 Proxy Statement\n\n  \n\n \n\nPay Versus Performance\n\n \n\nPAY VERSUS PERFORMANCE\n\nIn accordance with rules adopted by the SEC pursuant to the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010, and Item 402(v) of Regulation\nS-K,\nwe provide the following disclosure regarding executive compensation and Company performance for the years listed below. “Compensation Actually Paid” as presented in the following tables reflects\nSEC-mandated\nvaluation methodologies that incorporate\nyear-end\nstock prices and accounting adjustments. These figures may fluctuate significantly year-over-year and may not represent amounts actually realized in cash by executives during the year. The Committee evaluates compensation using both realized and realizable perspectives and considers alignment with long-term stockholder returns, peer performance, and internal pay equity. For further information concerning ATI’s variable\n\npay-for-performance\n\nphilosophy and how ATI aligns executive compensation with its performance, see “Executive Compensation — Compensation Discussion and Analysis.”\n\n \n\nYear\n\n \n\nSummary\n\nCompensation\nTable total for\nCEO Wetherbee\n($)\n(1)\n\n \n \n\nSummary\nCompensation\nTable total for\nCEO Fields\n($)\n(2)\n\n \n \n\nCompensation\nactually paid to\nCEO Wetherbee\n($)\n\n \n \n\nCompensation\nactually paid to\nCEO Fields\n\n($)\n\n \n \n\nAverage Summary\nCompensation\nTable total for\n\nnon-CEO\nNEOs\n($)\n(3)\n\n \n \n\nAverage\nCompensation\nactually paid to\n\nnon-CEO\n\nNEOs ($)\n(4)\n\n \n \n\nValue of initial fixed $100\ninvestment based on:\n\n \n \n\nNet Income\n\n($ in millions)\n\n \n \n\nATI Adjusted\nEBITDA\n($ in millions)\n(6)\n\n \n\n \n\nTotal\nshareholder\nreturn ($)\n\n \n \n\nPeer\ngroup total\nshareholder\nreturn ($)\n(5)\n\n \n\n2025\n \n \nN/A\n \n \n \n13,512,737\n \n \n \nN/A\n \n \n \n41,065,828\n \n \n \n3,520,647\n \n \n \n27,386,687\n \n \n \n697.38\n \n \n \n196.36\n \n \n \n404.3\n \n \n \n859.3\n \n\n2024\n \n \n7,173,761\n \n \n \n5,891,817\n \n \n \n41,116,787\n \n \n \n18,472,411\n \n \n \n3,033,063\n \n \n \n9,215,541\n \n \n \n330.65\n \n \n \n170.68\n \n \n \n367.8\n \n \n \n729.1\n \n\n2023\n \n \n7,670,554\n \n \n \nN/A\n \n \n \n35,206,270\n \n \n \nN/A\n \n \n \n2,902,853\n \n \n \n12,593,071\n \n \n \n271.14\n \n \n \n149.41\n \n \n \n410.8\n \n \n \n634.6\n \n\n2022\n \n \n11,007,608\n \n \n \nN/A\n \n \n \n32,090,373\n \n \n \nN/A\n \n \n \n4,410,737\n \n \n \n11,733,557\n \n \n \n178.06\n \n \n \n113.68\n \n \n \n323.5\n \n \n \n612.8\n \n\n2021\n \n \n7,590,345\n \n \n \nN/A\n \n \n \n6,677,580\n \n \n \nN/A\n \n \n \n2,792,700\n \n \n \n2,480,715\n \n \n \n94.99\n \n \n \n128.45\n \n \n \n184.6\n \n \n \n366.5\n \n\n \n\n(1)\n\nFor 2024, reflects total compensation for our former CEO, Robert S. Wetherbee, who was our “Principal Executive Officer” through June 30, 2024, as determined in accordance with Item 402(c) of Regulation\nS-K\n(“Item 402(c)”). For a reconciliation of Compensation Actually Paid to Total Compensation as reflected on the Company’s Summary Compensation Table for 2025, as shown on page 61 of this Proxy Statement (the “Summary Compensation Table”) for Mr. Wetherbee, see the immediately following table under the heading “Compensation Actually Paid to CEO.”\n\n \n\n(2)\n\nFor 2024, reflects total compensation for our current CEO,\nKimberly A. Fields\n, who became our “Principal Executive Officer” on July 1, 2024, as determined in accordance with Item 402(c) and reflected on the Summary Compensation Table. For a reconciliation of Compensation Actually Paid to Total Compensation as reflected on the Summary Compensation Table for Ms. Fields, see the immediately following table under the headings “Compensation Actually Paid to CEO.”\n\n \n\n(3)\n\nReflects the average total compensation for our\nnon-CEO\nNEOs as determined in accordance with Item 402(c) and reflected in the Summary Compensation Table for 2025, 2024, 2023, 2022 and 2021 as indicated. Compensation paid to the following executive officers is included in the average amounts shown for each such year:\n\n \n\n \n\n2025: Donald P. Newman, Vaishali S. Bhatia, Timothy J. Harris and Robert S. Wetherbee.\n\n \n\n \n\n2024: Messrs. Newman and Harris, Ms. Bhatia, Tina K. Busch and Elliot S. Davis. Ms. Busch, the Company’s former Senior Vice President and Chief Human Resources Officer, ceased to be an executive officer of the Company in December 2025, and Mr. Davis, the Company’s former Senior Vice President, General Counsel and Chief Compliance Officer, retired in 2024.\n\n \n\n \n\n2023: Ms. Fields and Messrs. Newman, Harris and Davis\n\n \n\n \n\n2022: Ms. Fields, Messrs. Newman and Davis, and Kevin B. Kramer, who ceased to serve as an executive officer of the Company in 2022 and retired in January 2024.\n\n \n\n \n\n2021: Ms. Fields and Messrs. Newman, Kramer and Davis\n\n \n\n(4)\n\nFor a reconciliation of average Compensation Actually Paid to average Total Compensation as reflected on the Summary Compensation Table for our\nnon-CEO\nNEOs, see the table below under the heading “Compensation Actually Paid to\nNon-CEO\nNEOs.”\n\n \n\n(5)\n\nThe peer group used for the purposes of this table is the S&P MidCap 400 Industrials Index.\n\n \n\n(6)\n\nThe Company Selected Measure for purposes of this table is ATI Adjusted EBITDA.\n\nThe following table sets forth the adjustments made during each year represented in the Pay Versus Performance Table to arrive at compensation “actually paid” to our CEO during each of the years in question. “Compensation Actually Paid” as presented in the following tables reflects\nSEC-mandated\nvaluation methodologies that incorporate\nyear-end\nstock prices and accounting adjustments. These figures may fluctuate significantly year-over-year and may not represent amounts actually realized in cash by executives during the year. The Committee evaluates compensation using both realized and realizable perspectives and considers alignment with long-term stockholder returns, peer performance, and internal pay equity.\n\n[Table of Contents](#toc)\n\n \n\n \n\n \n\n \n\n \n\nPay Versus Performance\n\n \n\n \n\nATI\n\n 2026 Proxy Statement\n\n \n \n \n\n \n\n75 \n\n \n\nCompensation Actually Paid to CEO\n\n \n\nYear\n\n \n\nAmounts Reflected in\n\nSummary Compensation Table ($)\n\n \n \n\nYE Fair Value of\nEquity Compensation\ngranted in\nCurrent Year ($)\n(4)\n\n \n \n\nChange in CY Fair\nValue of Unvested\nPrior Year Equity\nAwards ($)\n(5)\n\n \n \n\nChange in CY Fair\nValue of Equity\nAwards Vesting\nin CY ($)\n(5)\n\n \n  \n\nCompensation\nActually\n\nPaid ($)\n\n \n\n \n\nTotal\nCompensation\n(1)\n\n \n \n\nPension\nValue\n(2)\n\n \n \n\nEquity Value\n(3)\n\n \n\n2025\n \n \n13,512,737\n \n \n \n—\n \n \n \n(10,051,700)\n \n \n \n11,388,806\n \n \n \n14,054,649\n \n \n \n12,161,336\n \n  \n \n41,065,828\n \n\n2024 (Fields)\n \n \n5,891,817\n \n \n \n—\n \n \n \n(3,461,225)\n \n \n \n4,538,766\n \n \n \n3,989,042\n \n \n \n7,512,010\n \n  \n \n18,472,411\n \n\n2024 (Wetherbee)\n \n \n7,173,761\n \n \n \n(5,076\n) \n \n \n(4,518,727)\n \n \n \n11,507,917\n \n \n \n7,858,424\n \n \n \n19,100,489\n \n  \n \n41,116,787\n \n\n2023\n \n \n7,670,554\n \n \n \n(17,259\n) \n \n \n(4,774,796)\n \n \n \n8,913,063\n \n \n \n13,040,130\n \n \n \n10,374,578\n \n  \n \n35,206,270\n \n\n2022\n \n \n11,007,608\n \n \n \n—\n \n \n \n(7,555,702)\n \n \n \n18,204,232\n \n \n \n8,330,568\n \n \n \n2,103,668\n \n  \n \n32,090,373\n \n\n2021\n \n \n7,590,345\n \n \n \n—\n \n \n \n(4,428,259)\n \n \n \n3,040,422\n \n \n \n(43,181)\n \n \n \n518,253\n \n  \n \n6,677,580\n \n\n \n\n(1)\n\nAs determined in accordance with Item 402(c) and reflected on the Summary Compensation Table.\n\n \n\n(2)\n\nReflects the actuarial change in the present value of Mr. Wetherbee’s benefits under all defined benefit pension plans established by the Company, determined using interest rate and mortality rate assumptions consistent with those used in the Company’s financial statements. Effective December 31, 2014, the Company froze future benefit accruals in the ATI Pension Plan for all participating employees other than those in contractual employment arrangements. Also effective December 31, 2014, the Company froze the defined benefit-type\nnon-qualified\ndeferred compensation plans in which salaried employees participate, including the defined benefit portion of the ATI Benefit Restoration Plan in which Mr. Wetherbee participated.\n\n \n\n(3)\n\nAggregate grant date fair value, determined in accordance with FASB ASC Topic 718, of awards made under the Company’s LTIP. Grant date fair values for RSUs granted in each such year are based on the average of the high and low trading prices for a share of ATI stock on the applicable grant date. Grant date fair values for PSUs granted in each such year, including BPUs, were estimated using Monte Carlo simulations of stock price correlation, projected dividend yields and other variables over three-year time horizons matching the applicable PSU performance measurement periods.\n\n \n\n(4)\n\nAggregate\nyear-end\n2025, 2024, 2023, 2022 and 2021 (as applicable) fair value of the awards described in footnote (3) above.\nYear-end\nfair values for RSUs granted in each such year are based on the average of the high and low trading prices for a share of ATI stock on the last trading day of the applicable year.\nYear-end\nfair values for PSUs granted in each such year, including BPUs and EVAs, were estimated using Monte Carlo simulations of stock price correlation, projected dividend yields and other variables over three-year time horizons matching the applicable PSU performance measurement periods.\n\n \n\n(5)\n\nChanges in fair value determined by comparing fair values determined in the manner described above with comparable prior year values.\n\nThe following table sets forth the adjustments made during each year represented in the Pay Versus Performance Table to arrive at compensation “\nactually\npaid” to our\nnon-CEO\nNEOs during each of the years in question. “Compensation Actually Paid” as presented in the following tables reflects\nSEC-mandated\nvaluation methodologies that incorporate\nyear-end\nstock prices and accounting adjustments. These figures may fluctuate significantly year-over-year and may not represent amounts actually realized in cash by executives during the year. The Committee evaluates compensation using both realized and realizable perspectives and considers alignment with long-term stockholder returns, peer performance, and internal pay equity.\n\nCompensation Actually Paid to\nNon-CEO\nNEOs\n\n \n\nYear\n\n \n\nAmounts Reflected in\n\nSummary Compensation Table ($)\n\n \n \n\nYE Fair Value of\nEquity\nCompensation\ngranted in Current\nYear ($)\n(4)\n\n \n  \n\nChange in CY\nFair Value of\nUnvested Prior\nYear Equity\nAwards ($)\n(5)\n\n \n \n\nChange in CY\nFair Value of\nEquity Awards\nVesting in CY\n($)\n(5)\n\n \n  \n\nPrior Year-End\n\nFair Value of\nEquity Awards\nForfeited in CY\n($)\n\n \n  \n\nCompensation\nActually Paid\n($)\n\n \n\n \n\nTotal\nCompensation\n(1)\n\n \n  \n\nPension\nValue\n(2)\n\n \n  \n\nEquity Value\n(3)\n\n \n\n2025\n \n \n3,520,647\n \n  \n \n—\n \n  \n \n(1,961,681\n) \n \n \n3,512,325\n \n  \n \n11,023,052\n \n \n \n11,292,344\n \n  \n \n—\n \n  \n \n27,386,687\n \n\n2024\n \n \n3,033,063\n \n  \n \n—\n \n  \n \n(1,747,787\n) \n \n \n2,261,848\n \n  \n \n2,107,026\n \n \n \n3,561,390\n \n  \n \n—\n \n  \n \n9,215,541\n \n\n2023\n \n \n2,902,853\n \n  \n \n—\n \n  \n \n(1,549,120\n) \n \n \n2,776,371\n \n  \n \n5,712,179\n \n \n \n2,750,786\n \n  \n \n—\n \n  \n \n12,593,071\n \n\n2022\n \n \n4,410,737\n \n  \n \n—\n \n  \n \n(1,766,323\n) \n \n \n6,781,978\n \n  \n \n2,710,245\n \n \n \n596,920\n \n  \n \n—\n \n  \n \n11,733,557\n \n\n2021\n \n \n2,792,700\n \n  \n \n—\n \n  \n \n(1,392,976\n) \n \n \n1,003,087\n \n  \n \n(12,807\n) \n \n \n90,710\n \n  \n \n—\n \n  \n \n2,480,715\n \n\n \n\n(1)\n\nAs determined in accordance with Item 402(c) and reflected on the Summary Compensation Table.\n\n \n\n(2)\n\nEffective December 31, 2014, the Company froze future benefit accruals in the ATI Pension Plan for all participating employees other than those in contractual employment arrangements. Also effective December 31, 2014, the Company froze the defined benefit-type\nnon-qualified\ndeferred compensation plans in which salaried employees participate.\n\n \n\n(3)\n\nAverage grant date fair value, determined in accordance with FASB ASC Topic 718, of awards made to NEOs under the Company’s LTIP in 2025, 2024, 2023, 2022 and 2021 as indicated. Grant date fair values for RSUs granted in each such year are based on the average of the high and low trading prices for a share of ATI stock on the applicable grant date. Grant date fair values for PSUs granted in each such year, including BPUs, were estimated using Monte Carlo simulations of stock price correlation, projected dividend yields and other variables over three-year time horizons matching the applicable PSU performance measurement periods.\n\n \n\n(4)\n\nAverage\nyear-end\n2025, 2024, 2023, 2022 and 2021 (as applicable) fair value of the awards described in footnote (3) above.\nYear-end\nfair values for RSUs granted in each such year are based on the average of the high and low trading prices for a share of ATI stock on the last trading day of the applicable year.\nYear-end\nfair values for PSUs granted in each such year, including BPUs, were estimated using Monte Carlo simulations of stock price correlation, projected dividend yields and other variables over three-year time horizons matching the\napplicable\nPSU performance measurement periods.\n\n \n\n(5)\n\nChanges in fair value determined by comparing fair values determined in the manner described above with comparable prior year values.\n\n[Table of Contents](#toc)\n\n \n\n \n\n \n\n  \n\n \n\n76\n\n \n \n \n\n \n\nATI\n\n 2026 Proxy Statement\n\n  \n\n \n\nPay Versus Performance\n\n \n\nRelationship Between Pay and Performance\n\nThe following graphs show the relationship between “Compensation Actually Paid” to our CEO and other named executive officers in 2021, 2022, 2023, 2024 and 2025 to:\n\n \n\n \n\n◆\n\n \n\nOur Company Selected Performance Measure\n\n: ATI’s Adjusted EBITDA; and\n\n \n\n \n\n◆\n\n \n\nNet Income\n\n: ATI’s net income (loss) for the periods shown; and\n\n \n\n \n\n◆\n\n \n\nRelative TSR\n\n: ATI’s TSR and that of the S&P MidCap 400 Industrials Index.\n\n“Compensation Actually Paid” as presented in the following tables reflects\nSEC-mandated\nvaluation methodologies that incorporate\nyear-end\nstock prices and accounting adjustments. These figures may fluctuate significantly year-over-year and may not represent amounts actually realized in cash by executives during the year. The Committee evaluates compensation using both realized and realizable perspectives and considers alignment with long-term stockholder returns, peer performance, and internal pay equity.\n\n \n\n[Table of Contents](#toc)\n\n \n\n \n\n \n\n \n\n \n\nPay Versus Performance\n\n \n\n \n\nATI\n\n 2026 Proxy Statement\n\n \n \n \n\n \n\n77 \n\n \n\n2025 Performance Measures\n\nFor 2025, the performance measures listed below were identified as the most important to ATI’s compensation-setting process for named executive officers. The importance of EBITDA and cash flow is reflected in our use of these measures when setting performance standards applicable to our annual short-term incentive program, while the importance of both relative and absolute TSR are reflected in the performance criteria established for our longer-term, performance-vested equity awards.\n\n \n\n \n \n\nPerformance Measures:\n\n \n\n  \n\nOther Factors We Consider:\n\n \n\n \n \n\nNet Income\n\n \n\nAdjusted EBITDA\n\n \n\nOperating Cash Flow\n\n \n\nFree Cash Flow\n\n \n\nRelative Total Shareholder Return\n\n \n\nAbsolute Total Shareholder Return\n\n  \n\nAs discussed in greater detail in the “Compensation Discussion and Analysis” portion of this Proxy Statement, in addition to the performance measures listed here, our Compensation and Leadership Development Committee considers a range of factors in determining compensation, including among others: compensation levels among our benchmarking peer group; shareholder feedback; the advice of our independent compensation consultants and other advisors; our effectiveness in attracting and retaining the talent necessary to pursue our strategic goals; and the Committee’s overall evaluation of the individual performance of our CEO and each NEO, both in general and relative to their individual strategic goals for the year.\n\nReconciliations of Adjusted EBITDA to Net Income (Loss) Attributable to ATI (the most directly comparable GAAP measure) are provided (a) for 2025 on page 34 of our Annual Report on Form\n10-K\nfor the year ended December 28, 2025, which we filed with the SEC on February 20, 2026, (b) for 2024 on page 33 of our Annual Report on Form\n10-K\nfor the year ended December 29, 2024, which we filed with the SEC on February 21, 2025, (c) for 2023 on page 37 of our Annual Report on\nForm 10-K\nfor the year ended December 31, 2023, which we filed with the SEC on February 23, 2024, and (d) for 2022 and 2021, on page 32 of our Annual Report on Form\n10-K\nfor the year ended December 31, 2022, which we filed with the SEC on February 24, 2023.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n78\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nProposal 3: Ratification of the Selection of Independent Auditors Audit Committee Pre-Approval Policy\n\n \n\nProposal 3: Ratification of the\n\nSelection of Independent Auditors\n\nErnst & Young LLP serves as our independent registered public accounting firm (the “independent auditors”). They have unrestricted access to the Audit and Risk Committee to discuss audit findings and other financial matters. The Audit and Risk Committee believes that Ernst & Young is knowledgeable about ATI’s operations and accounting practices and is well qualified to act in the capacity of independent auditors.\n\nIn appointing Ernst & Young as our independent auditors for the 2026 fiscal year and making its recommendation that stockholders ratify the selection, the Audit and Risk Committee considered, among other matters, whether the audit and non-audit services Ernst & Young provides are compatible with maintaining the independence of our outside auditors. If our stockholders do not ratify the selection of Ernst & Young, the Audit and Risk Committee will reconsider the selection of Ernst & Young as the Company’s independent auditors. Representatives of Ernst & Young will be present at the Annual Meeting. They will be given the opportunity to make a statement if they desire to do so, and they will be available to respond to appropriate questions following the Annual Meeting.\n\nAUDIT COMMITTEE PRE-APPROVAL POLICY\n\nUnder ATI’s Audit and Risk Committee Pre-Approval Policy, the Audit and Risk Committee reviews and approves all services to be provided by Ernst & Young and the engagement terms and fees for such services before the firm is retained to perform any such services. While the Committee believes that the independent auditor may be able to provide tax services to the Company without impairing the auditor’s independence, absent unusual circumstances, the Committee does not expect to retain the independent auditor to provide tax services. Under the pre-approval policy, the Committee has delegated limited pre-approval authority to the Chair of the Committee with respect to permitted, non-tax related services. The Chair is required to report any pre-approval decisions to the Committee at its next scheduled meeting. The Audit and Risk Committee pre-approved all audit and non-audit services provided by Ernst & Young in 2025 and 2024.\n\nINDEPENDENT AUDITOR: SERVICES AND FEES\n\nThe fees and expenses of Ernst & Young for the indicated services performed during 2025 and 2024 were as follows (amounts in thousands):\n\n \n\n  \n  \n2025\n \n    \n2024\n \n\nAudit fees\n  \n \n$4,857\n \n    \n \n$4,928\n \n\nAudit-related fees\n  \n \n$0\n \n    \n \n$0\n \n\nTax fees\n  \n \n$0\n \n    \n \n$0\n \n\nAll other fees\n  \n \n$5\n \n    \n \n$6\n \n\nTotal\n  \n \n$4,862\n \n    \n \n$4,934\n \n\n“Audit fees” consisted of fees related to the annual audit of the Company’s consolidated financial statements and review of the consolidated financial statements in our Quarterly Reports on Form 10-Q, Sarbanes-Oxley Section 404 attestation services, audit and attestation services related to statutory or regulatory filings, the issuance of consents, and captive insurance company audits.\n\n“Audit-related fees” consisted of fees related to certain due diligence services and an audit of a pension plan.\n\n“Tax fees” consisted of certain tax consulting and compliance services for our international operations.\n\n“All other fees” consisted of subscriptions to Ernst & Young’s web-based EYOnline accounting reference library in both periods.\n\n \n\n \n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nAudit and Risk Committee Report Roles and Responsibilities\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n79 \n\n \n\nAudit and Risk Committee Report\n\nThe following is the report of the Audit and Risk Committee with respect to the Company’s audited consolidated financial statements for the fiscal year ended December 28, 2025.\n\nROLES AND RESPONSIBILITIES\n\nThe Audit and Risk Committee monitors and oversees the financial reporting process on behalf of the Board. Management has the primary responsibility for the Company’s internal controls and financial reporting process. The Committee reviews and discusses management’s report on internal control over financial reporting. Ernst & Young LLP, our independent auditor, is responsible for performing an independent audit of ATI’s financial statements in accordance with the standards of the Public Company Accounting Oversight Board (United States) (“PCAOB”), expressing an opinion as to their conformity with U.S. generally accepted accounting principles, and attesting to the effectiveness of ATI’s internal control over financial reporting.\n\nREQUIRED DISCLOSURES AND DISCUSSIONS\n\nThe Audit and Risk Committee has reviewed ATI’s financial statements, and has met and held discussions with ATI’s management, internal auditors, and the independent auditors regarding those financial statements, including a discussion of quality, not just acceptability, of the Company’s accounting principles, and Ernst & Young’s judgment regarding these matters.\n\nThe Audit and Risk Committee discussed with the internal auditors and independent auditors matters required to be discussed by the applicable requirements of the PCAOB. The Committee met with the internal auditors and independent auditors, with and without management present, to discuss the results of their examinations, their evaluations of the Company’s internal controls over financial reporting, and the overall quality of ATI’s financial reporting. The Audit and Risk Committee has also discussed with Ernst & Young matters required to be discussed by applicable auditing standards.\n\nThe Audit and Risk Committee has received the written disclosures and the letter from Ernst & Young required by applicable requirements of the PCAOB regarding the independent accountant’s communications with the Audit Committee concerning independence. The Committee also considered the compatibility of non-audit services with Ernst & Young’s independence. This information was also discussed with Ernst & Young.\n\nCOMMITTEE RECOMMENDS INCLUDING THE FINANCIAL STATEMENTS IN THE ANNUAL REPORT\n\nBased on the review and discussions referred to above, the Audit and Risk Committee recommended to the Board that the audited financial statements be included in our annual report on Form 10-K for the fiscal year ended December 28, 2025, as filed with the SEC. The Board of Directors has approved this inclusion.\n\nSubmitted by:\n\nAudit and Risk Committee\n\n \n\nChair:\n \nRuby Sharma\n\nMembers: \n \nLeroy M. Ball, Jr.\n\n \nHerbert J. Carlisle\n\n \n\nMarianne Kah\n\nElizabeth H. Lund\n\nJean Lydon-Rodgers\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n80\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nStock Ownership Information\n\n \n\nStock Ownership\n\nInformation\n\n \n\nFIVE PERCENT OWNERS OF COMMON STOCK\n\nThe entities listed in the following table are beneficial owners of five percent or more of ATI common stock as of December 31, 2025, based on information filed with the SEC. In general, “beneficial ownership” includes those shares a person has the power to vote or transfer currently, and shares such person has the right to acquire within 60 days.\n\n \n\nName and Address of Beneficial Owner\n  \nAmount and Nature of\nBeneficial Ownership\n \n    \nPercentage\nOf Class(1)\n \n\nCapital International Investors\n\n333 South Hope Street\n\nLos Angeles, CA 90071\n\n  \n \n17,638,463\n(2) \n    \n \n12.9%\n \n\nThe Vanguard Group\n\n1000 Vanguard Blvd.\n\nMalvern, PA 19355\n\n  \n \n13,895,719\n(3) \n    \n \n10.2%\n \n\nBlackRock, Inc.\n\n55 East 52nd Street\n\nNew York, NY 10055\n\n  \n \n13,891,604\n(4) \n    \n \n10.2%\n \n\nCapital World Investors\n\n333 South Hope Street\n\nLos Angeles, CA 90071\n\n  \n \n7,909,109\n(5) \n    \n \n5.8%\n \n\n \n\n(1)\n\nPercentages are based on shares of ATI common stock outstanding as of March 16, 2026, as of which date there were 136,462,390 shares of ATI common stock outstanding.\n\n \n\n(2)\n\nBased on a Schedule 13G/A filing under the Exchange Act, made on November 13, 2025, by Capital International Investors, a division of Capital Research and Management Company, reporting sole voting power with respect to 17,610,082 shares, and sole dispositive power with respect to 17,638,463 shares at September 30, 2025.\n\n \n\n(3)\n\nBased on a Schedule 13G/A filing under the Exchange Act, made on April 30, 2025, by The Vanguard Group reporting sole voting power with respect to 48,868 shares and sole dispositive power with respect to 13,694,200 shares at March 31, 2025.\n\n \n\n(4)\n\nBased on a Schedule 13G/A filing under the Exchange Act, made on October 3, 2025, by BlackRock, Inc., reporting sole voting power with respect to 13,436,277 shares and sole dispositive power with respect to 13,891,604 shares at September 30, 2025.\n\n \n\n(5)\n\nBased on Schedule 13G filing under the Exchange Act made of November 13, 2025 by Capital World Investors reporting sole voting power and sole dispositive power with respect to 7,909,109 shares at November 30, 2025.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nStock Ownership Information Stock Ownership of Directors, Board Nominees and Executive Management\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n81 \n\n \n\nSTOCK OWNERSHIP OF DIRECTORS, BOARD NOMINEES AND EXECUTIVE MANAGEMENT\n\nThe following table shows the shares of ATI common stock reported to ATI as beneficially owned as of March 16, 2026, by the nominees for director, the other current directors, each officer named in the Summary Compensation Table, and for all directors, executive officers and other statutory insiders as a group. Unless indicated otherwise below, the information provided in the following table is based on the Company’s records, information filed with the SEC, and information furnished by the respective individuals and includes as “beneficially owned” those shares that each such person has the power to vote or transfer currently, or the right to acquire within 60 days following March 16, 2026.\n\nFor biographical information regarding the beneficial owners, please see information under “Proposal 1—Election of Directors” and “Members of ATI’s Executive Management” of this Proxy Statement. The business address for each beneficial owner is c/o ATI Inc., 2021 McKinney Avenue, Suite 1100, Dallas, 75201.\n\n \n\nBeneficial Owner\n  \nAmount and Nature of\nBeneficial Ownership(1)\n \n    \nPercentage\nOf Class\n \n\nVaishali S. Bhatia\n  \n \n19,474\n \n    \n \n*\n \n\nLeroy M. Ball\n  \n \n33,832\n \n    \n \n*\n \n\nHerbert J. Carlisle\n  \n \n36,651\n \n    \n \n*\n \n\nCarolyn Corvi\n  \n \n70,240\n \n    \n \n*\n \n\nKimberly A. Fields\n  \n \n229,414\n \n    \n \n*\n \n\nTimothy J. Harris\n  \n \n151,058\n \n    \n \n*\n \n\nJ. Brett Harvey\n  \n \n98,869\n \n    \n \n*\n \n\nDavid P. Hess\n  \n \n34,040\n \n    \n \n*\n \n\nMarianne Kah\n  \n \n34,170\n \n    \n \n*\n \n\nElizabeth H. Lund\n  \n \n631\n \n    \n \n*\n \n\nJean Lydon-Rodgers\n  \n \n631\n \n    \n \n*\n \n\nDavid J. Morehouse\n  \n \n38,168\n \n    \n \n*\n \n\nDonald P. Newman\n  \n \n339,773\n \n    \n \n*\n \n\nRuby Sharma\n  \n \n6,380\n \n    \n \n*\n \n\nRobert S. Wetherbee\n  \n \n233,603\n \n    \n \n*\n \n\nAll directors, nominees and executive officers as a group (16 persons)\n  \n \n1,330,768\n \n    \n \n*\n \n\n*Indicates beneficial ownership of less than one percent (1%) of the outstanding shares of ATI common stock. As of March 16, 2026, there were 136,462,390 shares of ATI common stock outstanding.\n\n \n\n(1)\n\nThe table includes aggregate restricted stock awards as follows: (a) 2,054 shares for each of Ms. Corvi, Ms. Kah, Ms. Sharma and Messrs. Ball, Carlisle and Hess; (b) 4,889 shares for Mr. Harvey; (c) 631 shares for each of Ms. Lund and Ms. Lydon-Rodgers (d) 4,108 shares for Mr. Morehouse; and (e) 22,583 shares held by all directors, nominees and officers as a group. The table includes shares jointly held with named individuals’ spouses. The table does not generally include restricted stock units granted to our NEOs in 2024, 2025 and 2026, most of which do not vest within 60 days following March 16, 2026, except that the number of shares shown for Ms. Bhatia includes 10,191 shares of stock that vested on March 20, 2026.\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n82\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nAnnual Meeting Information 2026 Annual Meeting of Stockholders — Questions and Answers\n\n \n\nAnnual Meeting Information\n\n2026 ANNUAL MEETING OF STOCKHOLDERS — QUESTIONS AND ANSWERS\n\n \n\n1.\n\nHow can I attend, vote and ask questions at the virtual 2026 Annual Meeting?\n\nThe 2026 Annual Meeting will be conducted exclusively by webcast at www.meetnow.global/MSSZRJ5 on May 14, 2026, at 11:30 a.m. Central Time. We encourage you to access the 2026 Annual Meeting prior to the start time. Online access will begin at 11:15 a.m. Central Time.\n\nWe are committed to ensuring, to the extent possible, that our stockholders will be afforded the ability to participate at the virtual meeting like they would at an in-person meeting. You are entitled to participate, vote and submit questions at the 2026 Annual Meeting if you were a stockholder of record as of the close of business on March 16, 2026, the record date, or hold a legal proxy for the meeting provided by your bank, broker or nominee. No physical meeting will be held.\n\n \n\n \n \n\nFor Stockholders of Record\n  \n\nStockholders of record will be able to participate in the 2026 Annual Meeting, vote electronically and submit questions during the live webcast of the meeting, without advance registration. To access the live webcast of the meeting, you will need the 15-digit control number on the proxy card or the “Notice Regarding the Availability of Proxy Materials” (the “Notice”) you previously received.\n\n \n\nFor Beneficial Owners\n  \n\nIf you are a beneficial owner and hold your shares through an intermediary, such as a bank, broker or nominee, you must register in advance to participate in the 2026 Annual Meeting, vote electronically and submit questions during the live webcast of the meeting. To register in advance, you must obtain a legal proxy from the bank, broker or other nominee that holds your shares giving you the right to vote the shares. Please forward a copy of the legal proxy along with your email address to Computershare Trust Company, N.A. (“Computershare”).\n\n \n\nRequests for registration should be directed to Computershare by email at legalproxy@computershare.com no later than 5:00 p.m. Eastern Time, on Monday, May 11, 2026. You will receive a confirmation of your registration and instructions on how to attend the meeting by email after Computershare receives your registration materials.\n\n \n\nBeneficial owners who are unable to register in advance may still attend the 2026 Annual Meeting by visiting www.meetnow.global/MSSZRJ5 as a “guest” but will not have the option to vote shares electronically or submit questions during the live webcast of the meeting. However, we have provided additional methods so that all of our stockholders can submit questions. See “To submit a question” below.\n\n \n\nTo submit a question at the virtual 2026 Annual Meeting\n  \n\nIn Advance of the Meeting. Stockholders may submit questions in advance of the meeting by emailing their questions, along with proof of ownership, to investors@ATI Materials.com\n\n \n\nDuring the meeting. You may submit questions during the live webcast of the meeting by visiting the meeting website at www.meetnow.global/MSSZRJ5 and entering your control number. Once logged in, click on the “messages” icon at the top of the screen to type in your question, then click the arrow icon on the right to submit.\n\n \n\nThose who attend the 2026 Annual Meeting as a “guest,” as described above, will not have the option to submit questions during the live webcast of the meeting. However, you may email your question, along with proof of ownership, during the live meeting to investors@ATI Materials.com.\n\n \n\nQuestions pertinent to meeting matters will be answered during the meeting, subject to time constraints.\n\n \n\nFor technical support\n  \n\nIf you encounter technical difficulties with the virtual meeting platform on the day of the meeting, a link on the meeting page will provide further assistance, or you may call 1-888-724-2416 or 1-781-575-2748.\n\n \n\n \n\n2.\n\nWill you make a list of stockholders entitled to vote at the 2026 Annual Meeting available electronically?\n\nWe will make available a list of stockholders of record as of the record date for inspection by stockholders for any purpose germane to the meeting from April 30, 2026, through May 14, 2026, at our corporate offices or on request by email to investors@atimaterials.com. The list will also be available to stockholders at www.meetnow.global/MSSZRJ5 during the live webcast of the 2026 Annual Meeting.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nAnnual Meeting Information 2026 Annual Meeting of Stockholders — Questions and Answers\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n83 \n\n \n\n3.\n\nHow do I obtain materials for the Annual Meeting?\n\nWe are making this Proxy Statement and ATI’s 2025 Annual Report available to our stockholders electronically via the internet. On or about March 24, 2026, we began mailing to stockholders a Notice of Internet Availability of Proxy Materials containing instructions on how to access this Proxy Statement and the Annual Report and how to vote online. Unless you request a printed copy of the proxy materials by following the instructions for requesting such materials contained in the Notice, you will not receive a printed copy of the proxy materials. This Proxy Statement and our 2025 Annual Report are available to you at envisionreports.com/ATI and on our website at ATImaterials.com.\n\n \n\n4.\n\nWho is entitled to vote at the Annual Meeting?\n\nIf you held shares of ATI Inc. common stock at the close of business on March 16, 2026, you may vote your shares at the Annual Meeting. On that day, 136,462,390 shares of our common stock were outstanding.\n\nIn order to vote, you must either follow the instruction on your proxy card to designate a proxy to vote on your behalf or attend the meeting and vote your shares during the meeting. Even if you plan to attend the meeting, please return your proxy as soon as possible so that your shares are represented and will be voted and that we will have a quorum to conduct business if your plans change.\n\n \n\n5.\n\nHow do I cast my vote?\n\nThere are four different ways you may cast your vote. You may vote by:\n\n \n\nTelephone\n  \nusing the toll-free number listed on each proxy or voting instruction card\n\nOnline\n  \nat the web address provided on each proxy or voting instruction card\n\nMail\n  \nmarking, signing, dating and returning each proxy or voting instruction card in the postage-paid envelope provided. If you return your signed proxy card, but do not mark the boxes showing how you wish to vote on any particular item, your shares will be voted as the Board of Directors recommends for any such item.\n\nAttending and voting during\nthe Virtual Annual Meeting\n  \nonly if you are a stockholder of record (that is, your shares are registered directly in your name on the Company’s books and are not held in “street name” through a broker, bank or other nominee).\n\nIf you are a stockholder of record and wish to vote by telephone or electronically through the Internet, you will need to use the individual control number that is printed on your proxy card to authenticate your ownership. The deadline for voting by telephone or the Internet is 11:59 p.m. Eastern Time on May 13, 2026.\n\nIf your shares are held in “street name” (that is, they are held in the name of broker, bank or other nominee), or if your shares are held in one of the Company’s savings or retirement plans, you will receive instructions with your materials that you must follow in order to have your shares voted. For voting procedures for shares held in ATI’s savings or retirement plans, see the response to question 15 below.\n\n \n\n6.\n\nWhat is the difference between holding shares as a stockholder of record and as a beneficial owner?\n\nMost of our stockholders hold their shares through a broker, bank or other nominee rather than directly in their own name. As summarized below, there are some differences between shares held of record and those owned beneficially.\n\nStockholders of Record. If your shares are registered directly in your name with our transfer agent, Computershare, you are considered to be the stockholder of record with respect to those shares, and the Notice of Internet Availability of Proxy Materials is being sent directly to you. As the stockholder of record, you have the right to grant your voting proxy directly, to vote electronically, or to vote in person at the Annual Meeting. If you have requested printed materials, we have enclosed a proxy card for you to use.\n\nBeneficial Owners. If your shares are held in a stock brokerage account or by a bank or other nominee, you are considered the beneficial owner of shares held in “street name,” and the Notice of Internet Availability of Proxy Materials is being forwarded to you by your broker, bank or nominee who is considered to be the stockholder of record with respect to those shares. As the beneficial owner, you have the right to direct your broker, bank or nominee on how to vote and are also invited to attend the Annual Meeting. However, since you are not the stockholder of record, you may not vote these shares in person at the Annual Meeting unless you request, complete and deliver a legal voting proxy from your broker, bank or nominee. If you requested printed materials, your broker, bank or nominee has enclosed a voting instruction card for you to use in directing the broker, bank or nominee regarding how to vote your shares.\n\n \n\n7.\n\nI am a beneficial owner. Why do I need to request a legal proxy to be able to vote at the virtual meeting?\n\nIf your shares are held in an account at a bank, broker or other nominee, you are considered the beneficial owner of shares held in “street name” and the Notice was sent to you by your nominee. The bank, broker or other nominee holding your account is the\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n84\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nAnnual Meeting Information 2026 Annual Meeting of Stockholders — Questions and Answers\n\n \n\nstockholder of record for purposes of voting at the 2026 Annual Meeting. As a beneficial owner, you have the right to direct your bank, broker or nominee regarding how to vote the shares in your account. You are also invited to attend the virtual 2026 Annual Meeting. However, since you are not the stockholder of record, you may not vote your shares or submit questions during the meeting unless you request and obtain a “legal proxy” from your bank, broker or other nominee.\n\n \n\n8.\n\nWhat documentation can I provide as proof of my ownership?\n\nYou need to provide documentation showing that you owned ATI common stock on the record date of March 16, 2026. Documentation includes a copy of one of the following:\n\n \n\n \n◆\n \n\nyour proxy card or voting instruction form;\n\n \n\n \n◆\n \n\nthe Notice received by postal mail or e-mail; or\n\n \n\n \n◆\n \n\nan account statement or a brokerage statement reflecting your ownership.\n\n \n\n9.\n\nIf I submit my proxy do I still need to attend and vote during the virtual meeting?\n\nIf you have already submitted your proxy, there is no need to submit another proxy or vote at the 2026 Annual Meeting unless you wish to change or revoke your vote. Whether or not you plan to participate in the live webcast of the 2026 Annual Meeting, we urge you to vote and submit your proxy in advance of the meeting by one of the methods described in this Proxy Statement.\n\n \n\n10.\n\nIf I submit my proxy in advance, may I still attend the virtual meeting?\n\nIf you have already submitted your proxy, there is no need to submit another proxy or vote at the 2026 Annual Meeting unless you wish to change or revoke your vote, but you are still invited to attend the meeting if you choose. Stockholders of record and beneficial holders who wish to attend the 2026 Annual Meeting should follow the directions provided above under “How can I attend and vote at the 2026 Annual Meeting?”\n\n \n\n11.\n\n How many votes can be cast by all stockholders?\n\nEach share of ATI common stock is entitled to one vote for each director nominee and one vote for each other matter considered at the meeting. There is no cumulative voting. We had 136,462,390 shares of common stock outstanding and entitled to vote on the record date.\n\n \n\n12.\n\nHow many votes must be present to hold the Annual Meeting?\n\nA majority of the shares entitled to vote as of the record date must be present as part of the virtual meeting or by proxy in order to hold the Annual Meeting and conduct business. This is called a “quorum.” Your shares will be counted as present at the Annual Meeting if you properly cast your vote in person, electronically or telephonically, or a proxy card has been properly submitted by you or on your behalf. Both abstentions and broker non-votes are counted as present for the purpose of determining the presence of a quorum.\n\n \n\n13.\n\nWhat shares are included on the proxy or voting instruction card?\n\nThe shares indicated on your proxy or voting instruction card represent those shares registered directly in your name and shares held in the Company’s savings or retirement plans. If you do not cast your vote, your shares (except those held in the Company’s savings or retirement plans) will not be voted. See question 15 for an explanation of the voting procedures for shares in the Company’s savings or retirement plans.\n\n \n\n14.\n\nWhat does it mean if I receive more than one proxy or voting instruction card?\n\nIf your shares are registered differently and are in more than one account, then you will receive more than one card. Please complete and return all of the proxy or voting instruction cards you receive (or vote by telephone or the Internet all of the shares on each of the proxy or voting instruction cards you receive) so that all of your shares are voted.\n\n \n\n15.\n\nHow are shares that I hold in a company savings or retirement plan voted?\n\nIf you hold ATI common stock in one of the Company’s savings or retirement plans, then you may tell the plan trustee how to vote the shares allocated to your account. You may either sign and return the voting instruction card provided by the plan trustee or transmit your instructions by telephone or the Internet. If you do not transmit instructions, your plan shares will be voted as the plan administrator directs or as otherwise provided in the plan.\n\nThe deadline for voting the shares you hold in the Company’s savings or retirement plans by telephone or the Internet is 11:59 p.m. Eastern Time on May 12, 2026.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nAnnual Meeting Information 2026 Annual Meeting of Stockholders — Questions and Answers\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n85 \n\n \n\n16.\n\nIs my vote confidential?\n\nATI maintains a policy of keeping stockholder votes confidential.\n\n \n\n17. \n\nHow many votes are required to elect the directors and pass the other proposals?\n\n \n\nProposal 1: Election of Directors\n  \n\nWhile directors are elected by a plurality of votes cast, our Bylaws include a director resignation policy. This policy states that in an uncontested election, any director nominee who receives a greater number of votes “WITHHELD” from his or her election, as compared to votes “FOR” such election, must tender his or her resignation. The Nominating and Governance Committee of the Board is required to make recommendations to the Board regarding any tendered resignation. The Board will act on the tendered resignation within 90 days from the certification of the vote and will publicly disclose its decision, including its rationale.\n\n \n\nOnly votes “FOR” or “WITHHELD” are counted in determining whether a plurality has been cast in favor of a director nominee; abstentions are not counted for purposes of the election of directors. If you do not give authority to vote with respect to the election of some or all of the nominees, your shares will be considered broker non-votes and will not be voted with respect to the applicable nominees. For a “WITHHOLD” vote, your shares will be counted for purposes of determining whether there is a quorum and will have a similar effect as a vote against that director nominee for purposes of our director resignation policy.\n\n \n\nFull details of our director resignation policy are stated in our Bylaws, which are available on our website at ATImaterials.com.\n\nProposal 2: Advisory vote to approve the 2025 compensation of our named executive officers\n  \nProposal 2 will be approved if it receives the affirmative vote of at least a majority of the shares of ATI common stock represented at the Annual Meeting and entitled to vote on the matter, but is advisory, which means the result of the vote is non-binding. Although non-binding, the Board and its committees value the opinions of our stockholders and will review and consider the voting result when making future decisions regarding executive compensation. Abstentions and broker non-votes are not counted as votes for this proposal and will have no effect.\n\nProposal 3: Ratify Ernst & Young as our independent auditor for 2026\n  \nProposal 3 will be approved if it receives the affirmative vote of at least a majority of the shares of ATI common stock represented at the Annual Meeting and entitled to vote on the matter. Brokers are entitled to vote on Proposal 3 as a routine matter and, if your shares are represented at the Annual Meeting but you abstain from voting on Proposal 3, your shares will be counted as present and entitled to vote for purposes of establishing a quorum, and the abstention will have the same effect as a vote against the proposal.\n\n \n\n18.\n\nWhat if I don’t give specific voting instructions?\n\nStockholders of Record. If you are a stockholder of record and you indicate when voting by Internet or by telephone that you wish to vote as recommended by our Board, or if you return a signed proxy card but do not indicate how you wish to vote, then your shares will be voted:\n\n \n\n \n◆\n \n\nin accordance with the recommendations of the Board on all matters presented in this Proxy Statement; and\n\n \n\n \n◆\n \n\nas the proxy holders may determine in their discretion regarding any other matters properly presented for a vote at the meeting.\n\nIf you indicate a choice with respect to any matter to be acted upon on your proxy card, the shares will be voted in accordance with your instructions.\n\nBeneficial Owners. If you are a beneficial owner and hold your shares in street name and do not provide the organization that holds your shares with voting instructions, the broker or other nominee will determine if it has the discretionary authority to vote on each particular matter. In very limited circumstances, brokers have the discretion to vote on matters deemed to be routine. If you do not provide voting instructions to your broker, the broker could vote your shares in its discretion with respect to the proposal to ratify the selection of Ernst & Young as our independent auditors for 2026 (Proposal 3) because that is deemed to be a routine matter. For all other matters, if you do not provide instructions, your shares will be considered “broker non-votes” with regard to that matter. Broker non-votes will be counted for purposes of determining a quorum, but are not counted for purposes of determining the number of votes cast with respect to a particular proposal and are not considered to be shares entitled to vote on non-routine matters. Thus, a broker non-vote will not affect the outcome of the vote on Proposals 1 and 2. We encourage you to provide instructions to your broker regarding the voting of your shares.\n\n \n\n19.\n\nHow do I revoke or change my vote?\n\nYou may revoke your proxy or change your vote at any time before it is voted at the meeting by:\n\n \n\n \n◆\n \n\nnotifying the Corporate Secretary at ATI’s executive office;\n\n \n\n \n◆\n \n\ntransmitting a proxy dated later than your prior proxy, either by mail, telephone or Internet; or\n\n##### Table of Contents\n\n \n\n \n\n \n\n  \n\n \n\n86\n\n \n \n \n\n \n\nATI 2026 Proxy Statement\n\n  \n\n \n\nAnnual Meeting Information 2026 Annual Meeting of Stockholders — Questions and Answers\n\n \n\n \n◆\n \n\nattending the meeting and voting in person or by proxy (except for shares held in “street name” through a broker, bank or other nominee, or in the Company’s savings or retirement plans).\n\nThe latest-dated, timely, properly completed proxy that you submit, whether by mail, telephone or the Internet, will count as your vote. If a vote has been recorded for your shares and you subsequently submit a proxy card that is not properly signed and dated, the previously recorded vote will stand.\n\n \n\n20.\n\nCan I receive the Notice or other proxy materials over the internet?\n\nStockholders can elect to view future ATI notices and proxy materials over the Internet instead of receiving paper copies in the mail. This saves us the cost of producing and mailing these documents. Costs normally associated with electronic access, such as usage and telephone charges, will be borne by you.\n\n \n\n \n◆\n \n\nIf you are a stockholder of record and you choose to vote over the Internet, you can choose to receive future materials electronically by following the prompt on the internet voting page.\n\n \n\n \n◆\n \n\nIf you hold your Company stock in street name (such as through a broker, bank or other nominee account), check the information provided by your nominee for instructions on how to elect to view future notices and other materials over the Internet.\n\nStockholders who choose to view future proxy statements and annual reports over the Internet will receive instructions electronically that contain the Internet address for those materials, as well as voting instructions, approximately six weeks before future meetings, even in cases in which we otherwise mail full printed sets of our proxy materials.\n\nIf you enroll to view ATI’s future annual reports and proxy statements electronically and vote over the Internet, then your enrollment will remain in effect for all future stockholders’ meetings unless you cancel it. To cancel, stockholders of record should access computershare.com/investor and follow the instructions to cancel enrollment. You should retain the control number appearing on your enclosed proxy or voting instruction card. If you hold your Company stock in “street name,” check the information provided by your nominee holder for instructions on how to cancel your enrollment.\n\nIf at any time you would like to receive a paper copy of the annual report or proxy statement, please write to the Corporate Secretary, ATI Inc., 2021 McKinney Avenue, Dallas, Texas 75201.\n\n \n\n21.\n\nWhy did we only get one set of materials when there are two stockholders in my household?\n\nWe participate in an SEC-approved practice called “householding” that allows us to deliver only one Notice or set of proxy materials to stockholders of record who share the same address and last name unless we have received contrary instructions from one of you. Householding reduces our printing and mailing costs and our effect on the environment. Upon written or oral request, we will promptly deliver a separate annual report and proxy statement to any stockholder at a shared address to which a single copy of either of those documents was delivered.\n\nIf you would like to receive a printed copy of the Annual Report or Proxy Statement, or if you are a stockholder eligible for householding and would like to participate in householding, please send a request addressed to ATI’s Corporate Secretary at 2021 McKinney Avenue, Dallas, Texas 75201, or call (412) 394-2800. Many brokerage firms have instituted householding. If you hold your shares in “street name”, please contact your bank, broker or other holder of record to request information about householding.\n\n##### Table of Contents\n\n \n\n \n\n \n\n \n\n \n\nAnnual Meeting Information 2026 Annual Meeting of Stockholders — Questions and Answers\n\n \n\n \n\nATI 2026 Proxy Statement\n\n \n \n \n\n \n\n87 \n\n \n\n2027 ANNUAL MEETING AND STOCKHOLDER PROPOSALS\n\nStockholder proposals submitted for inclusion in the proxy statement and form of proxy relating to the 2027 Annual Meeting of Stockholders must be received no later than November 24, 2026. Stockholder proposals should be sent to the Corporate Secretary, ATI Inc., 2021 McKinney Avenue, Dallas, Texas 75201.\n\nIf you wish to submit director nominations or other business to be properly brought before an annual meeting, you must give timely notice of your intent to submit a proposal in writing to the Corporate Secretary. For such notices to be timely, notice must be received by the Corporate Secretary not less than 75 days and not more than 90 days before the first anniversary of the date of the preceding year’s annual meeting. This means that, for our 2027 Annual Meeting of Stockholders, we must receive any such notice between February 13, 2027, and February 28, 2027. The notice must contain certain information specified in the Company’s Certificate of Incorporation and Bylaws.\n\nThe Nominating and Governance Committee will consider director candidates recommended by stockholders. The Committee will evaluate stockholder-recommended candidates on the same basis as other candidates. Stockholder recommendations should be sent to the Corporate Secretary at the address above, who will forward the information to the Committee.\n\nStockholders may obtain copies of our Certificate of Incorporation and Bylaws by writing to the Corporate Secretary at the address set forth above. Copies of our Certificate of Incorporation and Bylaws have been filed with the SEC and can be viewed on our website, ATImaterials.com at “About ATI—Corporate Governance.”\n\nOTHER BUSINESS AND INFORMATION\n\nThe Company knows of no business to be presented for consideration at the meeting other than the proposals indicated in the Notice of Annual Meeting. If other matters are properly presented at the meeting, the persons designated as proxies on your proxy card may vote on such matters at their discretion.\n\nAnnual Report on Form 10-K\n\nCopies of ATI’s Annual Report on Form 10-K, without Exhibits, can be obtained free of charge by written request to the Corporate Secretary, ATI Inc., 2021 McKinney Avenue, Dallas, Texas 75201 or by calling (412) 394-2800.\n\nProxy Solicitation\n\nThis solicitation is being made on behalf of our Board of Directors. We pay the cost of preparing, assembling and mailing this proxy-soliciting material. We will reimburse banks, brokers and other nominee holders for reasonable expenses they incur in sending proxy materials to our beneficial stockholders whose stock is registered in the nominee’s name.\n\nATI has engaged Georgeson Inc., 199 Water Street, 26th Floor, New York, New York 10038 to help solicit proxies from brokers, banks and other nominee holders of ATI common stock at a cost of $11,000 plus expenses. Our employees also may solicit proxies for no additional compensation.\n\nOn behalf of the Board of Directors:\n\n \n\n \n\nAmanda J. Skov\n\nCorporate Secretary\n\nDated: March 24, 2026\n\n##### Table of Contents\n\nOur values.\nIntegrity\nWe do the right things the right way; it’s the\ncornerstone of our relationship with every stakeholder.\nSafety & Sustainability\nWe are committed to a Zero Injury Culture, protecting\nour people and the planet through our products and the\nway we operate.\nAccountability\nWe do what we say we are going to do. We set a\nstandard for excellence and hold ourselves and our team\naccountable for our actions, results and delivering value\nfor our customers.\nTeamwork & Respect\nWe seek and celebrate diverse views, capabilities and\nexperiences to power our collaborative work environment.\nInnovation\nWe embrace change and unique perspectives to create\nsustainable value, acting with urgency and taking\ncalculated risks to learn and continuously improve.\nATImaterials.com\nATI and Starburst logo are registered trademarks of ATI Properties, LLC | © 2026 ATI.\n\n##### Table of Contents\n\nUsing a black ink pen, mark your votes with an X as shown in this example. Please do not write outside the designated areas. Annual Meeting Proxy Card Your vote matters – here’s how to vote! You may vote online or by phone instead of mailing this card. Votes submitted electronically must be received by 11:59 p.m., Central Time, on May 11, 2026. Online Go to www.envisionreports.com/ati or scan the QR code — login details are located in the shaded bar below. Phone Call toll free 1-800-652-VOTE (8683) within the USA, US territories and Canada Save paper, time and money! Sign up for electronic delivery at www.envisionreports.com/ati T IF VOTING BY MAIL, SIGN, DETACH AND RETURN THE BOTTOM PORTION IN THE ENCLOSED ENVELOPE.T Proposals — The Board of Directors recommends a vote FOR all the nominees listed and FOR Proposals 2 and 3. A 1. Election of Directors: For Withhold For Withhold For Withhold 01 - Kimberly A. Fields 02 - Elizabeth H. Lund 03 - David J. Morehouse 2. Advisory vote to approve the compensation of our named executive officers B Authorized Signatures — This section must be completed for your vote to count. Please date and sign below. For Against Abstain For Against Abstain 3. Ratification of the election of Ernst & Young LLP as our independent auditors for 2026 Please sign EXACTLY as your name appears hereon. Joint owners should each sign. When signing as attorney, executor, administrator, trustee or guardian, or custodian, please give your full title as such. Date (mm/dd/yyyy) — Please print date below. Signature 1 — Please keep signature within the box. Signature 2 — Please keep signature within the box. 1 U P X 04945A\n\n##### Table of Contents\n\nThe ATI Retirement Plan The ATI 401(k) Savings Plan As a Plan participant, you have the right to direct Empower how to vote the shares of ATI Inc. Common Stock that are allocated to your Plan account and shown on the attached voting instruction card. The Trustee will hold your instructions in complete confidence except as may be necessary to meet legal requirements. You may vote by telephone, Internet or by completing, signing and returning voting instructions herein by mail. A postage-paid return envelope is enclosed. The Trustee must receive your voting instructions by 11:59 p.m., Central Time, on May 11, 2026. If the Trustee does not receive your instructions by such date, the Trustee shall vote your shares as the Plan Administrator directs. You will receive a separate set of proxy solicitation materials for any shares of Common Stock you own other than your Plan shares. Your non-Plan shares must be voted separately from your Plan shares. Important notice regarding the Internet availability of proxy materials for the Annual Meeting of Stockholders. The Proxy Statement and the 2025 Annual Report to Stockholders are available at: www.envisionreports.com/ati The 2026 Annual Meeting of Stockholders of ATI Inc. will be held on Thursday, May 14, 2026 at 11:30 a.m. Central Time, virtually via the internet at meetnow.global/MSSZRJ5. To access the virtual meeting, you must have the information that is printed in the shaded bar located on the reverse side of this form. Small steps make an impact. Help the environment by consenting to receive electronic delivery, sign up at www.envisionreports.com/ati IF VOTING BY MAIL, SIGN, DETACH AND RETURN THE BOTTOM PORTION IN THE ENCLOSED ENVELOPE Voting Instruction Card for 2026 Annual Meeting ATI Inc. Solicited on Behalf of the Board of Directors of ATI Inc. The undersigned hereby directs Empower to vote the full number of shares of Common Stock allocated to the account of the undersigned under the Plans, at the Annual Meeting of Stockholders of ATI Inc. on May 14, 2026 and any adjournments or postponements thereof, upon the matters set forth on the reverse of this card, and, in its discretion, upon such other matters as may properly come before such meeting. PLAN PARTICIPANTS MAY GIVE DIRECTIONS BY TOLL-FREE TELEPHONE OR INTERNET BY FOLLOWING THE INSTRUCTIONS ON THE REVERSE SIDE OR PARTICIPANTS MAY GIVE DIRECTIONS BY COMPLETING, DATING AND SIGNING THIS CARD AND RETURNING IT PROMPTLY IN THE ENCLOSED POSTAGE-PAID ENVELOPE. If you wish to use this card to vote your shares, please vote, date and sign on the reverse side. C Non-Voting Items Change of Address — Please print new address below.Comments — Please print your comments below. Meeting Attendance Mark box to the right if you plan to attend the Annual Meeting.\n\n##### Table of Contents\n\nUsing a black ink pen, mark your votes with an X as shown in this example. Please do not write outside the designated areas. Annual Meeting Proxy Card IF VOTING BY MAIL, SIGN, DETACH AND RETURN THE BOTTOM PORTION IN THE ENCLOSED ENVELOPE A Proposals — The Board of Directors recommends a vote FOR all the nominees listed and FOR Proposals 2 and 3. 1. Election of Directors: For Withhold 01 - Kimberly A. Fields 02 - Elizabeth H. Lund 03 - David J. Morehouse 2. Advisory vote to approve the compensation of our named executive officers For Against Abstain For Against Abstain 3. Ratification of the election of Ernst & Young LLP as our independent auditors for 2026 B Authorized Signatures — This section must be completed for your vote to count. Please date and sign below.Please sign EXACTLY as your name appears hereon. Joint owners should each sign. When signing as attorney, executor, administrator, trustee or guardian, or custodian, please give your full title as such. Date (mm/dd/yyyy) — Please print date below. Signature 1 — Please keep signature within the box. Signature 2 — Please keep signature within the box. 1 U P X 04943A\n\n##### Table of Contents\n\nIF VOTING BY MAIL, SIGN, DETACH AND RETURN THE BOTTOM PORTION IN THE ENCLOSED ENVELOPE. Proxy — ATI Inc.Proxy for 2026 Annual Meeting Solicited on Behalf of the Board of Directors of ATI Inc. The undersigned hereby appoints Vaishali S. Bhatia, James Robert Foster and Amanda J. Skov, or any of them, each with power of substitution and revocation, proxies or proxy to vote all shares of Common Stock which the stockholder named herein is entitled to vote with all powers which the stockholder would possess if personally present, at the Annual Meeting of Stockholders of ATI Inc. on May 14, 2026, and any adjournments or postponements thereof, upon the matters set forth on the reverse side of this card and, in their discretion, upon such other matters as may properly come before such meeting. STOCKHOLDERS MAY VOTE BY TOLL-FREE TELEPHONE OR THE INTERNET BY FOLLOWING THE INSTRUCTIONS ON THE REVERSE SIDE OR STOCKHOLDERS MAY VOTE BY COMPLETING, DATING AND SIGNING THIS PROXY CARD AND RETURNING IT PROMPTLY IN THE ENCLOSED POSTAGE-PAID ENVELOPE. This proxy, when properly executed, will be voted as directed herein, but if you do not specify a vote, the proxies will vote FOR Items 1, 2 and 3 and in their discretion on other matters. If you wish to use this card to vote your shares, please vote, date and sign on the reverse side. (Continued and to be marked, dated and signed, on the other side)\n\n##### Table of Contents\n\nUsing a black ink pen, mark your votes with an X as shown in this example. Please do not write outside the designated areas. Your vote matters – here’s how to vote! You may vote online or by phone instead of mailing this card. Online Go to www.envisionreports.com/ati or scan the QR code — login details are located in the shaded bar below. Phone Call toll free 1-800-652-VOTE (8683) within the USA, US territories and Canada Save paper, time and money! Sign up for electronic delivery at www.envisionreports.com/ati Annual Meeting Proxy Card IF VOTING BY MAIL, SIGN, DETACH AND RETURN THE BOTTOM PORTION IN THE ENCLOSED ENVELOPE. A Proposals — The Board of Directors recommends a vote FOR all the nominees listed and FOR Proposals 2 and 3. 1. Election of Directors: For Withhold For Withhold For Withhold 01 - Kimberly A. Fields 02 - Elizabeth H. Lund 03 - David J. Morehouse 2. Advisory vote to approve the compensation of our named executive officers For Against Abstain 3. Ratification of the election of Ernst & Young LLP as our independent auditors for 2026 B Authorized Signatures — This section must be completed for your vote to count. Please date and sign below. Please sign EXACTLY as your name appears hereon. Joint owners should each sign. When signing as attorney, executor, administrator, trustee or guardian, or custodian, please give your full title as such. Date (mm/dd/yyyy) — Please print date below. Signature 1 — Please keep signature within the box. Signature 2 — Please keep signature within the box. 1 U P X 04942A\n\n##### Table of Contents\n\n2026 Annual Meeting of ATI Inc. Stockholders Thursday, May 14, 2026 11:30 a.m. Central Time Dear Stockholder, Available on the Internet at http://www.envisionreports.com/ati are materials relating to the ATI Inc. 2026 Annual Meeting of Stockholders. The Notice of the Meeting and Proxy Statement describe the formal business to be transacted at the meeting. Your vote is important. Please vote your proxy promptly whether or not you expect to attend the meeting. You may vote by toll-free telephone, by Internet or by signing and returning the proxy card (below) by mail in the enclosed postage-paid envelope. Amanda J. Skov Corporate Secretary Important notice regarding the Internet availability of proxy materials for the Annual Meeting of Stockholders. The Proxy Statement and the 2025 Annual Report to Stockholders are available at: www.envisionreports.com/ati The 2026 Annual Meeting of Stockholders of ATI Inc. will be held on Thursday, May 14, 2026 at 11:30 a.m. Central Time, virtually via the internet at meetnow.global/MSSZRJ5. To access the virtual meeting, you must have the information that is printed in the shaded bar located on the reverse side of this form. Small steps make an impact. Help the environment by consenting to receive electronic delivery, sign up at www.envisionreports.com/ati IF VOTING BY MAIL, SIGN, DETACH AND RETURN THE BOTTOM PORTION IN THE ENCLOSED ENVELOPE. Proxy — ATI Inc. Proxy for 2026 Annual Meeting Solicited on Behalf of the Board of Directors of ATI Inc. The undersigned hereby appoints Vaishali S. Bhatia, James Robert Foster and Amanda J. Skov, or any of them, each with power of substitution and revocation, proxies or proxy to vote all shares of Common Stock which the stockholder named herein is entitled to vote with all powers which the stockholder would possess if personally present, at the Annual Meeting of Stockholders of ATI Inc. on May 14, 2026, and any adjournments or postponements thereof, upon the matters set forth on the reverse side of this card and, in their discretion, upon such other matters as may properly come before such meeting. STOCKHOLDERS MAY VOTE BY TOLL-FREE TELEPHONE OR THE INTERNET BY FOLLOWING THE INSTRUCTIONS ON THE REVERSE SIDE OR STOCKHOLDERS MAY VOTE BY COMPLETING, DATING AND SIGNING THIS PROXY CARD AND RETURNING IT PROMPTLY IN THE ENCLOSED POSTAGE-PAID ENVELOPE. This proxy, when properly executed, will be voted as directed herein, but if you do not specify a vote, the proxies will vote FOR Items 1, 2 and 3 and in their discretion on other matters. If you wish to use this card to vote your shares, please vote, date and sign on the reverse side. (Continued and to be marked, dated and signed, on the other side) C Non-Voting Items Change of Address — Please print new address below. Comments — Please print your comments below. Meeting Attendance Mark box to the right if you plan to attend the Annual Meeting."}