26 CFR § 20.2046-1 - Disclaimed property.
(a) This section shall apply to the disclaimer or renunciation of an interest in the person disclaiming by a transfer made after December 31, 1976. For rules relating to when the transfer creating the interest occurs, see § 25.2518-2(c)(3) and (c)(4) of this chapter. If a qualified disclaimer is made with respect to such a transfer, the Federal estate tax provisions are to apply with respect to the property interest disclaimed as if the interest had never been transferred to the person making the disclaimer. See section 2518 and the corresponding regulations for rules relating to a qualified disclaimer.
(b) The first and second sentences of this section are applicable for transfers creating the interest to be disclaimed made on or after December 31, 1997.