26 CFR §1.481-6

1. (a)Sections 1.481-1, 1.481-2, 1.481-3, and 1.481-4 are effective for Consent Agreements signed on or after December 27, 1994. For Consent Agreements signed before December 27, 1994, see §§ 1.481-1, 1.481-2, 1.481-3, 1.481-4, and 1.481-5 as contained in 26 CFR part 1, revised as of April 1, 1995.
2. (b)Section 1.481-5 applies to taxable years beginning October 20, 2020. However, a corporation may choose to apply the rules in §§ 1.481-5, 1.1371-1, and 1.1371-2 in their entirety to taxable years beginning on or before October 20, 2020. If a corporation makes the choice described in the previous sentence, the corporation must continue to apply the rules in §§ 1.481-5, 1.1371-1, and 1.1371-2 in their entirety for the corporation's subsequent taxable years.