This document contains final regulations providing guidance about the limitation on the deduction for business interest expense after amendment of the Internal Revenue Code (Code) by the provisions commonly known as the Tax Cuts and Jobs Act, which was enacted on December 22, 2017, and the Coronavirus Aid, Relief, and Economic Security Act, which was enacted on March 27, 2020. The regulations provide guidance to taxpayers on how to calculate the limitation, what constitutes interest for purposes of the limitation, which taxpayers and trades or businesses are subject to the limitation, and how the limitation applies in consolidated group, partnership, international, and other contexts.