TREASURY REGULATIONS

(a) Donor who is surviving spouse is limited to DSUE amount of last deceased spouse—(1) In general. In computing a surviving spouse's gift tax liability with regard to a transfer subject to the tax imposed by section 2501 (taxable gift), a deceased spousal unused exclusion (DSUE) amount of a decedent, computed under § 20.2010-2(c), is included in determining the surviving spouse's applicable exclusion amount under section 2010(c)(2), provided:

(i) Such decedent is the last deceased spouse of such surviving spouse within the meaning of § 20.2010-1(e)(5) at the time of the surviving spouse's taxable gift; and

(ii) The executor of the decedent's estate elected portability (see § 20.2010-2(a) and (b) for applicable requirements).

(2) No DSUE amount available from last deceased spouse. If on the date of the surviving spouse's taxable gift the last deceased spouse of such surviving spouse had no DSUE amount or if the executor of the estate of such last deceased spouse did not elect portability, the surviving spouse has no DSUE amount (except as and to the extent provided in paragraph (c)(1)(ii) of this section) to be included in determining his or her applicable exclusion amount, even if the surviving spouse previously had a DSUE amount available from another decedent who, prior to the death of the last deceased spouse, was the last deceased spouse of such surviving spouse. See paragraph (c) of this section for a special rule in the case of multiple deceased spouses.

(3) Identity of last deceased spouse unchanged by subsequent marriage or divorce. A decedent is the last deceased spouse (as defined in § 20.2010-1(e)(5)) of a surviving spouse even if, on the date of the surviving spouse's taxable gift, the surviving spouse is married to another (then-living) individual. If a surviving spouse marries again and that marriage ends in divorce or an annulment, the subsequent death of the divorced spouse does not end the status of the prior deceased spouse as the last deceased spouse of the surviving spouse. The divorced spouse, not being married to the surviving spouse at death, is not the last deceased spouse as that term is defined in § 20.2010-1(e)(5).

(b) Manner in which DSUE amount is applied. If a donor who is a surviving spouse makes a taxable gift and a DSUE amount is included in determining the surviving spouse's applicable exclusion amount under section 2010(c)(2), such surviving spouse will be considered to apply such DSUE amount to the taxable gift before the surviving spouse's own basic exclusion amount.

(c) Special rule in case of multiple deceased spouses and previously-applied DSUE amount—(1) In general. A special rule applies to compute the DSUE amount included in the applicable exclusion amount of a surviving spouse who previously has applied the DSUE amount of one or more deceased spouses. If a surviving spouse applied the DSUE amount of one or more (successive) last deceased spouses to the surviving spouse's previous lifetime transfers, and if any of those last deceased spouses is different from the surviving spouse's last deceased spouse as defined in § 20.2010-1(e)(5) at the time of the current taxable gift by the surviving spouse, then the DSUE amount to be included in determining the applicable exclusion amount of the surviving spouse that will be applicable at the time of the current taxable gift is the sum of—

(i) The DSUE amount of the surviving spouse's last deceased spouse as described in paragraph (a)(1) of this section; and

(ii) The DSUE amount of each other deceased spouse of the surviving spouse to the extent that such amount was applied to one or more previous taxable gifts of the surviving spouse.

(2) Example. The following example, in which all described individuals are U.S. citizens, illustrates the application of this paragraph (c):

(d) Date DSUE amount taken into consideration by donor who is a surviving spouse—(1) General rule. A portability election made by an executor of a decedent's estate (see § 20.2010-2(a) and (b) for applicable requirements) generally applies as of the date of such decedent's death. Thus, the decedent's DSUE amount is included in the applicable exclusion amount of the decedent's surviving spouse under section 2010(c)(2) and will be applicable to transfers made by the surviving spouse after the decedent's death (subject to the limitations in paragraph (a) of this section). However, such decedent's DSUE amount will not be included in the applicable exclusion amount of the surviving spouse, even if the surviving spouse had made a taxable gift in reliance on the availability or computation of the decedent's DSUE amount:

(i) If the executor of the decedent's estate supersedes the portability election by filing a subsequent estate tax return in accordance with § 20.2010-2(a)(4);

(ii) To the extent that the DSUE amount subsequently is reduced by a valuation adjustment or the correction of an error in calculation; or

(iii) To the extent that the DSUE amount claimed on the decedent's return cannot be determined.

(2) Exception when surviving spouse not a U.S. citizen on date of deceased spouse's death. If a surviving spouse becomes a citizen of the United States after the death of the surviving spouse's last deceased spouse, the DSUE amount of the surviving spouse's last deceased spouse becomes available to the surviving spouse on the date the surviving spouse becomes a citizen of the United States (subject to the limitations in paragraph (a) of this section). However, when the special rule regarding qualified domestic trusts in paragraph (d)(3) of this section applies, the earliest date on which a decedent's DSUE amount may be included in the applicable exclusion amount of such decedent's surviving spouse who becomes a U.S. citizen is as provided in paragraph (d)(3) of this section.

(3) Special rule when property passes to surviving spouse in a qualified domestic trust—(i) In general. When property passes from a decedent for the benefit of the decedent's surviving spouse in one or more qualified domestic trusts (QDOT) as defined in section 2056A(a) and the decedent's executor elects portability, the DSUE amount available to be included in the applicable exclusion amount of the surviving spouse under section 2010(c)(2) is the DSUE amount of the decedent as redetermined in accordance with § 20.2010-2(c)(4) (subject to the limitations in paragraph (a) of this section). The earliest date on which such decedent's DSUE amount may be included in the applicable exclusion amount of the surviving spouse under section 2010(c)(2) is the date of the occurrence of the final QDOT distribution or final other event (generally, the termination of all QDOTs created by or funded with assets passing from the decedent or the death of the surviving spouse) on which tax under section 2056A is imposed. However, the decedent's DSUE amount as redetermined in accordance with § 20.2010-2(c)(4) may be applied to the surviving spouse's taxable gifts made in the year of the surviving spouse's death or, if the terminating event occurs prior to the surviving spouse's death, then in the year of that terminating event and/or in any subsequent year during the surviving spouse's life.

(ii) Surviving spouse becomes a U.S. citizen. If a surviving spouse for whom property has passed from a decedent in one or more QDOTs becomes a citizen of the United States and the requirements in section 2056A(b)(12) and the corresponding regulations are satisfied, then the date on which such decedent's DSUE amount may be included in the applicable exclusion amount of the surviving spouse under section 2010(c)(2) (subject to the limitations in paragraph (a) of this section) is the date on which the surviving spouse becomes a citizen of the United States. See § 20.2010-2(c)(4) for the rules for computing the decedent's DSUE amount in the case of a qualified domestic trust.

(iii) Example. The following example illustrates the application of this paragraph (d)(3):

(e) Authority to examine returns of deceased spouses. For the purpose of determining the DSUE amount to be included in the applicable exclusion amount of a surviving spouse, the Internal Revenue Service (IRS) may examine returns of each of the surviving spouse's deceased spouses whose DSUE amount is claimed to be included in the surviving spouse's applicable exclusion amount, regardless of whether the period of limitations on assessment has expired for any such return. The IRS's authority to examine returns of a deceased spouse applies with respect to each transfer by the surviving spouse to which a DSUE amount is or has been applied. Upon examination, the IRS may adjust or eliminate the DSUE amount reported on such a return of a deceased spouse; however, the IRS may assess additional tax on that return only if that tax is assessed within the period of limitations on assessment under section 6501 applicable to the tax shown on that return. See also section 7602 for the IRS's authority, when ascertaining the correctness of any return, to examine any returns that may be relevant or material to such inquiry.

(f) Availability of DSUE amount for nonresidents who are not citizens. A nonresident surviving spouse who was not a citizen of the United States at the time of making a transfer subject to tax under chapter 12 of the Internal Revenue Code shall not take into account the DSUE amount of any deceased spouse except to the extent allowed under any applicable treaty obligation of the United States. See section 2102(b)(3).

(g) Effective/applicability date. This section applies to gifts made on or after June 12, 2015. See 26 CFR 25.2505-2T, as contained in 26 CFR part 25, revised as of April 1, 2015, for the rules applicable to gifts made on or after January 1, 2011, and before June 12, 2015.