26 C.F.R. § 1.678(d)-1 Renunciation of power.
Title 26 - Internal Revenue
Section 678(a) does not apply to a power which has been renounced or disclaimed within a reasonable time after the holder of the power first became aware of its existence.
Title 26: Internal Revenue
PART 1—INCOME TAXES
grantors and others treated as substantial owners
§ 1.678(d)-1 Renunciation of power.