26 CFR § 20.2056A-10 - Surviving spouse becomes citizen after QDOT established.
(a) Section 2056A estate tax no longer imposed under certain circumstances. Section 2056A(b)(12) provides that a QDOT is no longer subject to the imposition of the section 2056A estate tax if the surviving spouse becomes a citizen of the United States and the following conditions are satisfied—
(1) The spouse either was a United States resident (for the definition of resident for this purpose, see § 20.2056A–1(b)) at all times after the death of the decedent and before becoming a United States citizen, or no taxable distributions are made from the QDOT before the spouse becomes a United States citizen (regardless of the residency status of the spouse); and
(2) The U.S. Trustee(s) of the QDOT notifies the Internal Revenue Service and certifies in writing that the surviving spouse has become a United States citizen. Notice is to be made by filing a final Form 706–QDT on or before April 15th of the calendar year following the year in which the surviving spouse becomes a United States citizen, unless an extension of time for filing is granted under section 6081.
(b) Special election by spouse. If the surviving spouse becomes a United States citizen and the spouse is not a United States resident at all times after the death of the decedent and before becoming a United States citizen, and a tax was previously imposed under section 2056A(b)(1)(A) with respect to any distribution from the QDOT before the surviving spouse becomes a United States citizen, the estate tax imposed under section 2056A(b)(1) does not apply to distributions after the spouse becomes a citizen if—
(1) The spouse elects to treat any taxable distribution from the QDOT prior to the spouse's election as a taxable gift made by the spouse for purposes of section 2001(b)(1)(B) (referring to adjusted taxable gifts), and for purposes of determining the amount of the tax imposed by section 2501 on actual taxable gifts made by the spouse during the year in which the spouse becomes a citizen or in any subsequent year;
(2) The spouse elects to treat any previous reduction in the section 2056A estate tax by reason of the decedent's unified credit (under either section 2010 or section 2102(c)) as a reduction in the spouse's unified credit under section 2505 for purposes of determining the amount of the credit allowable with respect to taxable gifts made by the surviving spouse during the taxable year in which the spouse becomes a citizen, or in any subsequent year; and
(3) The elections referred to in this paragraph (b) are made by timely filing a Form 706–QDT on or before April 15th of the year following the year in which the surviving spouse becomes a citizen (unless an extension of time for filing is granted under section 6081) and attaching notification of the election to the return.