This document contains final regulations concerning the deduction for qualified business income (QBI) under section 199A of the Internal Revenue Code (Code). The regulations will affect certain individuals, partnerships, S corporations, trusts, and estates. The regulations provide guidance on the treatment of previously suspended losses included in qualified business income. The regulations also provide guidance on the determination of the section 199A deduction for taxpayers that hold interests in regulated investment companies, split- interest trusts, and charitable remainder trusts.