This document contains final regulations that provide guidance on the tax consequences of the transition away from the use of certain interbank offered rates in debt instruments, derivative contracts, and other contracts. The final regulations are necessary to address the possibility that a modification of the terms of a contract to replace such an interbank offered rate with a new reference rate could result in the realization of income, deduction, gain, or loss for Federal income tax purposes or could have other tax consequences. The final regulations will affect parties to contracts that reference certain interbank offered rates.