{"url_path":"/sec/miax/proxy/2026-04-27/000162828026027314","section_key":"body","section_title":"DEFA14A body","topic":"sec","document":{"doc_type":"DEFA14A","doc_date":"2026-04-27","source_url":"https://www.sec.gov/Archives/edgar/data/1438472/0001628280-26-027314-index.html","accession_number":"0001628280-26-027314","cik":"0001438472","ticker":"MIAX","issuer_name":"MIAMI INTERNATIONAL HOLDINGS, INC.","edgar_url":"https://www.sec.gov/Archives/edgar/data/1438472/0001628280-26-027314-index.html","primary_entity_key":"0001438472","primary_entity_name":"MIAMI INTERNATIONAL HOLDINGS, INC."},"word_count":151,"has_tables":true,"body_markdown":"DEFA14A\n1\ndefa14a-noticeandproxycard.htm\nDEFA14A\n\nDEFA 14A - Notice and Proxy Card\n\nUNITED STATES\n\nSECURITIES AND EXCHANGE COMMISSION\n\nWashington, D.C. 20549\n\nSCHEDULE 14A\n\nProxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934\n\n(Amendment No. )\n\nFiled by the Registrant ☒\n\nFiled by a party other than the Registrant ☐\n\nCheck the appropriate box:\n\n☐\n\nPreliminary Proxy Statement\n\n☐\n\nConfidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))\n\n☐\n\nDefinitive Proxy Statement\n\n☒\n\nDefinitive Additional Materials\n\n☐\n\nSoliciting Material under §240.14a-12\n\nMiami International Holdings, Inc.\n\n(Name of Registrant as Specified In Its Charter)\n\nThomas P. Gallagher\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\nNo fee required\n\n☐\n\nFee paid previously with preliminary materials\n\n☐\n\nFee computed on table in exhibit required by Item 25(b) per Exchange Act Rules\n\n14a-6(i)(1) and 0-11\n\n1"}