---
kind: "range"
citation: "26 C.F.R. §§ 20.2010-1–20.2010-3"
title: "26"
from: "20.2010-1"
to: "20.2010-3"
count: 3
url: "https://uscodex.org/cfr/26/20.2010-1..20.2010-3"
---

# §20.2010-1. Unified credit against estate tax; in general.

- (a) **General rule.** [Section 2010(a)](/cfr/26/2010.md?p=a) allows the estate of every decedent a credit against the estate tax imposed by [section 2001](/cfr/26/2001.md). The allowable credit is the applicable credit amount. See [paragraph (e)(1)](#e-1) of this section for an explanation of the term applicable credit amount.
- (b) **Special rule in case of certain gifts made before 1977.** The applicable credit amount allowable under [paragraph (a)](#a) of this section must be reduced by an amount equal to 20 percent of the aggregate amount allowed as a specific exemption under [section 2521](/cfr/26/2521.md) (as in effect before its repeal by the Tax Reform Act of 1976) for gifts made by the decedent after September 8, 1976, and before January 1, 1977.
- (c) **Special rule in the case of a difference between the basic exclusion amount applicable to gifts and that applicable at the donor's date of death.** Changes in the basic exclusion amount that occur between the date of a donor's gift and the date of the donor's death may cause the basic exclusion amount allowable on the date of a gift to exceed that allowable on the date of death. If the total of the amounts allowable as a credit in computing the gift tax payable on the decedent's post-1976 gifts, within the meaning of [section 2001(b)(2)](/cfr/26/2001.md?p=b-2), to the extent such credits are based solely on the basic exclusion amount as defined and adjusted in [section 2010(c)(3)](/cfr/26/2010.md?p=c-3), exceeds the credit allowable within the meaning of [section 2010(a)](/cfr/26/2010.md?p=a) in computing the estate tax, again only to the extent such credit is based solely on such basic exclusion amount, in each case by applying the tax rates in effect at the decedent's death, then the portion of the credit allowable in computing the estate tax on the decedent's taxable estate that is attributable to the basic exclusion amount is the sum of the amounts attributable to the basic exclusion amount allowable as a credit in computing the gift tax payable on the decedent's post-1976 gifts.
  - (1) **Computational rules.** For purposes of this [paragraph (c)](#c):
    - (i) **In determining the amounts allowable as a credit—**
      - (A) The amount allowable as a credit in computing gift tax payable for any calendar period may not exceed the tentative tax on the gifts made during that period ([section 2505(c)](/cfr/26/2505.md?p=c)); and
      - (B) The amount allowable as a credit in computing the estate tax may not exceed the net tentative tax on the taxable estate ([section 2010(d)](/cfr/26/2010.md?p=d)).
    - (ii) In determining the extent to which an amount allowable as a credit in computing gift tax payable is based solely on the basic exclusion amount:
      - (A) Any deceased spousal unused exclusion (DSUE) amount available to the decedent is deemed to be applied to gifts made by the decedent before the decedent's basic exclusion amount is applied to those gifts (see §§ [20.2010-3(b)](/cfr/26/20.2010-3.md?p=b) and [25.2505-2(b)](/cfr/26/25.2505-2.md?p=b));
      - (B) In a calendar period in which the applicable exclusion amount allowable with regard to gifts made during that period includes amounts other than the basic exclusion amount, the allowable basic exclusion amount may not exceed that necessary to reduce the tentative gift tax to zero; and
      - (C) In a calendar period in which the applicable exclusion amount allowable with regard to gifts made during that period includes amounts other than the basic exclusion amount, the portion of the credit based solely on the basic exclusion amount is that which corresponds to the result of dividing the basic exclusion amount allocable to those gifts by the applicable exclusion amount allocable to those gifts.
    - (iii) In determining the extent to which an amount allowable as a credit in computing the estate tax is based solely on the basic exclusion amount, the credit is computed as if the applicable exclusion amount were limited to the basic exclusion amount.
  - (2) **Examples.** All basic exclusion amounts include hypothetical inflation adjustments. Unless otherwise stated, in each example the decedent's date of death is after 2025.
    - (i) **Example 1.** Individual A (never married) made cumulative post-1976 taxable gifts of $9 million, all of which were sheltered from gift tax by the cumulative total of $11.4 million in basic exclusion amount allowable on the dates of the gifts. The basic exclusion amount on A's date of death is $6.8 million. A was not eligible for any restored exclusion amount pursuant to Notice 2017-15. Because the total of the amounts allowable as a credit in computing the gift tax payable on A's post-1976 gifts (based on the $9 million of basic exclusion amount used to determine those credits) exceeds the credit based on the $6.8 million basic exclusion amount allowable on A's date of death, this [paragraph (c)](#c) applies, and the credit for purposes of computing A's estate tax is based on a basic exclusion amount of $9 million, the amount used to determine the credits allowable in computing the gift tax payable on A's post-1976 gifts.
    - (ii) **Example 2.** Assume that the facts are the same as in Example 1 of [paragraph (c)(2)(i)](#c-2-i) of this section except that A made cumulative post-1976 taxable gifts of $4 million. Because the total of the amounts allowable as a credit in computing the gift tax payable on A's post-1976 gifts is less than the credit based on the $6.8 million basic exclusion amount allowable on A's date of death, this [paragraph (c)](#c) does not apply. The credit to be applied for purposes of computing A's estate tax is based on the $6.8 million basic exclusion amount as of A's date of death, subject to the limitation of [section 2010(d)](/cfr/26/2010.md?p=d).
    - (iii) **Example 3.** Individual B's predeceased spouse, C, died before 2026, at a time when the basic exclusion amount was $11.4 million. C had made no taxable gifts and had no taxable estate. C's executor elected, pursuant to [§ 20.2010-2](/cfr/26/20.2010-2.md), to allow B to take into account C's $11.4 million DSUE amount. B made no taxable gifts and did not remarry. The basic exclusion amount on B's date of death is $6.8 million. Because the total of the amounts allowable as a credit in computing the gift tax payable on B's post-1976 gifts attributable to the basic exclusion amount (zero) is less than the credit based on the basic exclusion amount allowable on B's date of death, this [paragraph (c)](#c) does not apply. The credit to be applied for purposes of computing B's estate tax is based on B's $18.2 million applicable exclusion amount, consisting of the $6.8 million basic exclusion amount on B's date of death plus the $11.4 million DSUE amount, subject to the limitation of [section 2010(d)](/cfr/26/2010.md?p=d).
    - (iv) **Example 4.** Assume the facts are the same as in Example 3 of [paragraph (c)(2)(iii)](#c-2-iii) of this section except that, after C's death and before 2026, B makes taxable gifts of $14 million in a year when the basic exclusion amount is $12 million. B is considered to apply the DSUE amount to the gifts before applying B's basic exclusion amount. The amount allowable as a credit in computing the gift tax payable on B's post-1976 gifts for that year ($5,545,800) is the tax on $14 million, consisting of $11.4 million in DSUE amount and $2.6 million in basic exclusion amount. This basic exclusion amount is 18.6 percent of the $14 million exclusion amount allocable to those gifts, with the result that $1,031,519 (0.186 × $5,545,800) of the amount allowable as a credit for that year in computing gift tax payable is based solely on the basic exclusion amount. The amount allowable as a credit based solely on the basic exclusion amount for purposes of computing B's estate tax ($2,665,800) is the tax on the $6.8 million basic exclusion amount on B's date of death. Because the portion of the credit allowable in computing the gift tax payable on B's post-1976 gifts based solely on the basic exclusion amount ($1,031,519) is less than the credit based solely on the basic exclusion amount ($2,665,800) allowable on B's date of death, this [paragraph (c)](#c) does not apply. The credit to be applied for purposes of computing B's estate tax is based on B's $18.2 million applicable exclusion amount, consisting of the $6.8 million basic exclusion amount on B's date of death plus the $11.4 million DSUE amount, subject to the limitation of [section 2010(d)](/cfr/26/2010.md?p=d).
  - (3) [Reserved]
- (d) **Credit limitation.** The applicable credit amount allowed under [paragraph (a)](#a) of this section cannot exceed the amount of the estate tax imposed by [section 2001](/cfr/26/2001.md).
- (e) **Explanation of terms.** The explanation of terms in this section applies to this section and to §§ [20.2010-2](/cfr/26/20.2010-2.md) and [20.2010-3](/cfr/26/20.2010-3.md).
  - (1) **Applicable credit amount.** The term applicable credit amount refers to the allowable credit against estate tax imposed by [section 2001](/cfr/26/2001.md) and gift tax imposed by [section 2501](/cfr/26/2501.md). The applicable credit amount equals the amount of the tentative tax that would be determined under [section 2001(c)](/cfr/26/2001.md?p=c) if the amount on which such tentative tax is to be computed were equal to the applicable exclusion amount. The applicable credit amount is determined by applying the unified rate schedule in [section 2001(c)](/cfr/26/2001.md?p=c) to the applicable exclusion amount.
  - (2) **Applicable exclusion amount.** The applicable exclusion amount equals the sum of the basic exclusion amount and, in the case of a surviving spouse, the deceased spousal unused exclusion (DSUE) amount.
  - (3) **Basic exclusion amount.** Except to the extent provided in [paragraph (e)(3)(iii)](#e-3-iii) of this section, the basic exclusion amount is the sum of the amounts described in paragraphs [(e)(3)(i)](#e-3-i) and [(ii)](#e-3-ii) of this section.
    - (i) For any decedent dying in calendar year 2011 or thereafter, $5,000,000; and
    - (ii) For any decedent dying after calendar year 2011 and before calendar year 2018, $5,000,000 multiplied by the cost-of-living adjustment determined under [section 1(f)(3)](/cfr/26/1.md?p=f-3) for the calendar year of the decedent's death by substituting “calendar year 2010” for “calendar year 1992” in [section 1(f)(3)(B)](/cfr/26/1.md?p=f-3-B) and by rounding to the nearest multiple of $10,000. For any decedent dying after calendar year 2017, $5,000,000 multiplied by the cost-of-living adjustment determined under [section 1(f)(3)](/cfr/26/1.md?p=f-3) for the calendar year of the decedent's death by substituting “calendar year 2010” for “calendar year 2016” in [section 1(f)(3)(A)(ii)](/cfr/26/1.md?p=f-3-A-ii) and rounded to the nearest multiple of $10,000.
    - (iii) For any decedent dying after calendar year 2017, and before calendar year 2026, paragraphs [(e)(3)(i)](#e-3-i) and [(ii)](#e-3-ii) of this section will be applied by substituting “$10,000,000” for “$5,000,000.”
  - (4) **Deceased spousal unused exclusion (DSUE) amount.** The term DSUE amount refers, generally, to the unused portion of a decedent's applicable exclusion amount to the extent this amount does not exceed the basic exclusion amount in effect in the year of the decedent's death. For the rules on computing the DSUE amount, see §§ [20.2010-2(c)](/cfr/26/20.2010-2.md?p=c) and [20.2010-3(b)](/cfr/26/20.2010-3.md?p=b).
  - (5) **Last deceased spouse.** The term last deceased spouse means the most recently deceased individual who, at that individual's death after December 31, 2010, was married to the surviving spouse. See §§ [20.2010-3(a)](/cfr/26/20.2010-3.md?p=a) and [25.2505-2(a)](/cfr/26/25.2505-2.md?p=a) for additional rules pertaining to the identity of the last deceased spouse for purposes of determining the applicable exclusion amount of the surviving spouse.
- (f) **Applicability dates—**
  - (1) **In general.** Except as provided in [paragraph (f)(2)](#f-2) of this section, this section applies to the estates of decedents dying after June 11, 2015. For the rules applicable to estates of decedents dying after December 31, 2010, and before June 12, 2015, see [§ 20.2010-1T](/cfr/26/20.2010-1T.md), as contained in [26 CFR part 20](/cfr/26/part20.md), revised as of April 1, 2015.
  - (2) **Exceptions.** Paragraphs [(c)](#c) and [(e)(3)](#e-3) of this section apply to estates of decedents dying on and after November 26, 2019. However, [paragraph (e)(3)](#e-3) of this section may be applied by estates of decedents dying after December 31, 2017, and before November 26, 2019. For the explanation of the basic exclusion amount applicable to estates of decedents dying after June 11, 2015, and before January 1, 2018, see [§ 20.2010-1(d)(3)](#d-3), as contained in [26 CFR part 20](/cfr/26/part20.md), revised as of April 1, 2019.

# §20.2010-2. Portability provisions applicable to estate of a decedent survived by a spouse.

- (a) **Election required for portability.** To allow a decedent's surviving spouse to take into account that decedent's deceased spousal unused exclusion (DSUE) amount, the executor of the decedent's estate must elect portability of the DSUE amount on a timely filed Form 706, “United States Estate (and Generation-Skipping Transfer) Tax Return” (estate tax return). This election is referred to in this section and in [§ 20.2010-3](/cfr/26/20.2010-3.md) as the portability election.
  - (1) **Timely filing required.** An estate that elects portability will be considered, for purposes of subtitle B and subtitle F of the Internal Revenue Code (Code), to be required to file a return under [section 6018(a)](/cfr/26/6018.md?p=a). Accordingly, the due date of an estate tax return required to elect portability is nine months after the decedent's date of death or the last day of the period covered by an extension (if an extension of time for filing has been obtained). See §§ [20.6075-1](/cfr/26/20.6075-1.md) and [20.6081-1](/cfr/26/20.6081-1.md) for additional rules relating to the time for filing estate tax returns. An extension of time to elect portability under this [paragraph (a)](#a) will not be granted under [§ 301.9100-3](/cfr/26/301.9100-3.md) of this chapter to an estate that is required to file an estate tax return under [section 6018(a)](/cfr/26/6018.md?p=a), as determined without regard to this [paragraph (a)](#a). Such an extension, however, may be available under the procedures applicable under §§ [301.9100-1](/cfr/26/301.9100-1.md) and [301.9100-3](/cfr/26/301.9100-3.md) of this chapter to an estate that is not required to file a return under [section 6018(a)](/cfr/26/6018.md?p=a), as determined without regard to this [paragraph (a)](#a).
  - (2) **Portability election upon filing of estate tax return.** Upon the timely filing of a complete and properly prepared estate tax return, an executor of an estate of a decedent survived by a spouse will have elected portability of the decedent's DSUE amount unless the executor chooses not to elect portability and satisfies the requirement in [paragraph (a)(3)(i)](#a-3-i) of this section. See [paragraph (a)(7)](#a-7) of this section for the return requirements related to the portability election.
  - (3) **Portability election not made; requirements for election not to apply.** The executor of the estate of a decedent survived by a spouse will not make or be considered to make the portability election if either of the following applies:
    - (i) The executor states affirmatively on a timely filed estate tax return, or in an attachment to that estate tax return, that the estate is not electing portability under [section 2010(c)(5)](/cfr/26/2010.md?p=c-5). The manner in which the executor may make this affirmative statement on the estate tax return is as set forth in the instructions issued with respect to such form (“Instructions for Form 706”).
    - (ii) The executor does not timely file an estate tax return in accordance with [paragraph (a)(1)](#a-1) of this section.
  - (4) **Election irrevocable.** An executor of the estate of a decedent survived by a spouse who timely files an estate tax return may make or may supersede a portability election previously made, provided that the estate tax return reporting the election or the superseding election is filed on or before the due date of the return, including extensions actually granted. However, see [paragraph (a)(6)](#a-6) of this section when contrary elections are made by more than one person permitted to make the election. The portability election, once made, becomes irrevocable once the due date of the estate tax return, including extensions actually granted, has passed.
  - (5) **Estates eligible to make the election.** An executor may elect portability on behalf of the estate of a decedent survived by a spouse if the decedent dies on or after January 1, 2011. However, an executor of the estate of a nonresident decedent who was not a citizen of the United States at the time of death may not elect portability on behalf of that decedent, and the timely filing of such a decedent's estate tax return will not constitute the making of a portability election.
  - (6) **Persons permitted to make the election—**
    - (i) **Appointed executor.** An executor or administrator of the estate of a decedent survived by a spouse that is appointed, qualified, and acting within the United States, within the meaning of [section 2203](/cfr/26/2203.md) (an appointed executor), may timely file the estate tax return on behalf of the estate of the decedent and, in so doing, elect portability of the decedent's DSUE amount. An appointed executor also may elect not to have portability apply pursuant to [paragraph (a)(3)](#a-3) of this section.
    - (ii) **Non-appointed executor.** If there is no appointed executor, any person in actual or constructive possession of any property of the decedent (a non-appointed executor) may timely file the estate tax return on behalf of the estate of the decedent and, in so doing, elect portability of the decedent's DSUE amount, or, by complying with [paragraph (a)(3)](#a-3) of this section, may elect not to have portability apply. A portability election made by a non-appointed executor when there is no appointed executor for that decedent's estate can be superseded by a subsequent contrary election made by an appointed executor of that same decedent's estate on an estate tax return filed on or before the due date of the return, including extensions actually granted. An election to allow portability made by a non-appointed executor cannot be superseded by a contrary election to have portability not apply made by another non-appointed executor of that same decedent's estate (unless such other non-appointed executor is the successor of the non-appointed executor who made the election). See [§ 20.6018-2](/cfr/26/20.6018-2.md) for additional rules relating to persons permitted to file the estate tax return.
  - (7) **Requirements of return—**
    - (i) **General rule.** An estate tax return will be considered complete and properly prepared for purposes of this section if it is prepared in accordance with the instructions issued for the estate tax return (Instructions for Form 706) and if the requirements of §§ [20.6018-2](/cfr/26/20.6018-2.md), [20.6018-3](/cfr/26/20.6018-3.md), and [20.6018-4](/cfr/26/20.6018-4.md) are satisfied. However, see [paragraph (a)(7)(ii)](#a-7-ii) of this section for reduced requirements applicable to certain property of certain estates.
    - (ii) **Reporting of value not required for certain property—**
      - (A) **In general.** A special rule applies with respect to certain property of estates in which the executor is not required to file an estate tax return under [section 6018(a)](/cfr/26/6018.md?p=a), as determined without regard to [paragraph (a)(1)](#a-1) of this section. With respect to such an estate, for bequests, devises, or transfers of property included in the gross estate, the value of which is deductible under section [2056](/cfr/26/2056.md) or [2056A](/cfr/26/2056A.md) (marital deduction property) or under [section 2055(a)](/cfr/26/2055.md?p=a) (charitable deduction property), an executor is not required to report a value for such property on the estate tax return (except to the extent provided in this [paragraph (a)(7)(ii)(A)](#a-7-ii-A)) and will be required to report only the description, ownership, and/or beneficiary of such property, along with all other information necessary to establish the right of the estate to the deduction in accordance with §§ [20.2056(a)-1(b)(i)](/cfr/26/20.2056..1.md) through [(iii)](/cfr/26/20.2056.md?p=iii) and [20.2055-1(c)](/cfr/26/20.2055-1.md?p=c), as applicable. However, this rule does not apply in certain circumstances as provided in this [paragraph (a)](#a) and as may be further described in guidance issued from time to time by publication in the Internal Revenue Bulletin (see [§ 601.601(d)(2)(ii)(b)](/cfr/26/601.601.md?p=d-2-ii-b) of this chapter). In particular, this rule does not apply to marital deduction property or charitable deduction property if—

        (1) The value of such property relates to, affects, or is needed to determine, the value passing from the decedent to a recipient other than the recipient of the marital or charitable deduction property;

        (2) The value of such property is needed to determine the estate's eligibility for the provisions of sections [2032](/cfr/26/2032.md), [2032A](/cfr/26/2032A.md), or another estate or generation-skipping transfer tax provision of the Code for which the value of such property or the value of the gross estate or adjusted gross estate must be known (not including section 1014 of the Code);

        (3) Less than the entire value of an interest in property includible in the decedent's gross estate is marital deduction property or charitable deduction property; or

        (4) A partial disclaimer or partial qualified terminable interest property (QTIP) election is made with respect to a bequest, devise, or transfer of property includible in the gross estate, part of which is marital deduction property or charitable deduction property.

      - (B) **Return requirements when reporting of value not required for certain property.** [Paragraph (a)(7)(ii)(A)](#a-7-ii-A) of this section applies only if the executor exercises due diligence to estimate the fair market value of the gross estate, including the property described in [paragraph (a)(7)(ii)(A)](#a-7-ii-A) of this section. Using the executor's best estimate of the value of properties to which [paragraph (a)(7)(ii)(A)](#a-7-ii-A) of this section applies, the executor must report on the estate tax return, under penalties of perjury, the amount corresponding to the particular range within which falls the executor's best estimate of the total gross estate, in accordance with the Instructions for Form 706.
      - (C) **Examples.** The following examples illustrate the application of [paragraph (a)(7)(ii)](#a-7-ii) of this section. In each example, assume that Husband (H) dies in 2015, survived by his wife (W), that both H and W are U.S. citizens, that H's gross estate does not exceed the excess of the applicable exclusion amount for the year of his death over the total amount of H's adjusted taxable gifts and any specific exemption under [section 2521](/cfr/26/2521.md), and that H's executor (E) timely files Form 706 solely to make the portability election.
- (b) **Requirement for DSUE computation on estate tax return.** [Section 2010(c)(5)(A)](/cfr/26/2010.md?p=c-5-A) requires an executor of a decedent's estate to include a computation of the DSUE amount on the estate tax return to elect portability and thereby allow the decedent's surviving spouse to take into account that decedent's DSUE amount. This requirement is satisfied by the timely filing of a complete and properly prepared estate tax return, as long as the executor has not elected out of portability as described in [paragraph (a)(3)(i)](#a-3-i) of this section. See [paragraph (a)(7)](#a-7) of this section for the requirements for a return to be considered complete and properly prepared.
- (c) **Computation of the DSUE amount—**
  - (1) **General rule.** Subject to [paragraphs (c)(2) through (4)](#c-2..c-4) of this section, the DSUE amount of a decedent with a surviving spouse is the lesser of the following amounts—
    - (i) The basic exclusion amount in effect in the year of the death of the decedent; or
    - (ii) **The excess of—**
      - (A) The decedent's applicable exclusion amount; over
      - (B) The sum of the amount of the taxable estate and the amount of the adjusted taxable gifts of the decedent, which together is the amount on which the tentative tax on the decedent's estate is determined under [section 2001(b)(1)](/cfr/26/2001.md?p=b-1).
  - (2) **Special rule to consider gift taxes paid by decedent.** Solely for purposes of computing the decedent's DSUE amount, the amount of the adjusted taxable gifts of the decedent referred to in [paragraph (c)(1)(ii)(B)](#c-1-ii-B) of this section is reduced by the amount, if any, on which gift taxes were paid for the calendar year of the gift(s).
  - (3) **Impact of applicable credits.** An estate's eligibility under [sections 2012 through 2015](/cfr/26/2012..2015.md) for credits against the tax imposed by [section 2001](/cfr/26/2001.md) does not impact the computation of the DSUE amount.
  - (4) **Special rule in case of property passing to qualified domestic trust—**
    - (i) **In general.** When property passes for the benefit of a surviving spouse in a qualified domestic trust (QDOT) as defined in [section 2056A(a)](/cfr/26/2056A.md?p=a), the DSUE amount of the decedent is computed on the decedent's estate tax return for the purpose of electing portability in the same manner as this amount is computed under [paragraph (c)(1)](#c-1) of this section, but this DSUE amount is subject to subsequent adjustments. The DSUE amount of the decedent must be redetermined upon the occurrence of the final distribution or 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 estate tax is imposed under [section 2056A](/cfr/26/2056A.md). See [§ 20.2056A-6](/cfr/26/20.2056A-6.md) for the rules on determining the estate tax under [section 2056A](/cfr/26/2056A.md). See [§ 20.2010-3(c)(3)](/cfr/26/20.2010-3.md?p=c-3) regarding the timing of the availability of the decedent's DSUE amount to the surviving spouse.
    - (ii) **Surviving spouse becomes a U.S. citizen.** If the surviving spouse becomes a U.S. citizen and if the requirements of [section 2056A(b)(12)](/cfr/26/2056A.md?p=b-12) and the corresponding regulations are satisfied, the estate tax imposed under [section 2056A(b)(1)](/cfr/26/2056A.md?p=b-1) ceases to apply. Accordingly, no estate tax will be imposed under [section 2056A](/cfr/26/2056A.md) either on subsequent QDOT distributions or on the property remaining in the QDOT on the surviving spouse's death and the decedent's DSUE amount is no longer subject to adjustment.
  - (5) **Examples.** The following examples illustrate the application of this [paragraph (c)](#c):
- (d) **Authority to examine returns of decedent.** The IRS may examine returns of a decedent in determining the decedent's DSUE amount, regardless of whether the period of limitations on assessment has expired for that return. See [§ 20.2010-3(d)](/cfr/26/20.2010-3.md?p=d) for additional rules relating to the IRS's authority to examine returns. See also [section 7602](/cfr/26/7602.md) 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.
- (e) **Effective/applicability date.** This section applies to the estates of decedents dying on or after June 12, 2015. See [26 CFR 20.2010-2T](/cfr/26/20.2010-2T.md), as contained in [26 CFR part 20](/cfr/26/part20.md), revised as of April 1, 2015, for the rule applicable to estates of decedents dying on or after January 1, 2011, and before June 12, 2015.

# §20.2010-3. Portability provisions applicable to the surviving spouse's estate.

- (a) **Surviving spouse's estate limited to DSUE amount of last deceased spouse—**
  - (1) **In general.** The deceased spousal unused exclusion (DSUE) amount of a decedent, computed under [§ 20.2010-2(c)](/cfr/26/20.2010-2.md?p=c), is included in determining the surviving spouse's applicable exclusion amount under [section 2010(c)(2)](/cfr/26/2010.md?p=c-2), provided—
    - (i) Such decedent is the last deceased spouse of such surviving spouse within the meaning of [§ 20.2010-1(e)(5)](/cfr/26/20.2010-1.md?p=e-5) on the date of the death of the surviving spouse; and
    - (ii) The executor of the decedent's estate elected portability (see § [20.2010-2(a)](/cfr/26/20.2010-2.md?p=a) and [(b)](/cfr/26/20.2010-2.md?p=b) for applicable requirements).
  - (2) **No DSUE amount available from last deceased spouse.** If the last deceased spouse of such surviving spouse had no DSUE amount, or if the executor of such a decedent's estate did not make a portability election, the surviving spouse's estate has no DSUE amount (except as provided in [paragraph (b)(1)(ii)](#b-1-ii) of this section) to be included in determining the 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 (b)](#b) of this section for a special rule in the case of multiple deceased spouses and a previously applied DSUE amount.
  - (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)](/cfr/26/20.2010-1.md?p=e-5)) of a surviving spouse even if, on the date of the death of the surviving spouse, 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)](/cfr/26/20.2010-1.md?p=e-5).
- (b) **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 to taxable gifts in accordance with § [25.2505-2(b)](/cfr/26/25.2505-2.md?p=b) and [(c)](/cfr/26/25.2505-2.md?p=c). If a surviving spouse has applied the DSUE amount of one or more (successive) last deceased spouses to the surviving spouse's transfers during life, 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)](/cfr/26/20.2010-1.md?p=e-5) at the time of the surviving spouse's death, then the DSUE amount to be included in determining the applicable exclusion amount of the surviving spouse at the time of the surviving spouse's death is the sum of—
    - (i) The DSUE amount of the surviving spouse's last deceased spouse as described in [paragraph (a)(1)](#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 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 (b)](#b):
- (c) **Date DSUE amount taken into consideration by surviving spouse's estate—**
  - (1) **General rule.** A portability election made by an executor of a decedent's estate (see § [20.2010-2(a)](/cfr/26/20.2010-2.md?p=a) and [(b)](/cfr/26/20.2010-2.md?p=b) for applicable requirements) generally applies as of the date of the decedent's death. Thus, such decedent's DSUE amount is included in the applicable exclusion amount of the decedent's surviving spouse under [section 2010(c)(2)](/cfr/26/2010.md?p=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)](#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 transfer 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)](/cfr/26/20.2010-2.md?p=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 surviving spouse cannot substantiate the DSUE amount claimed on the surviving spouse's return.
  - (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)](#a) of this section). However, when the special rule regarding qualified domestic trusts in [paragraph (c)(3)](#c-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 (c)(3)](#c-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)](/cfr/26/2056A.md?p=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)](/cfr/26/2010.md?p=c-2) is the DSUE amount of the decedent as redetermined in accordance with [§ 20.2010-2(c)(4)](/cfr/26/20.2010-2.md?p=c-4) (subject to the limitations in [paragraph (a)](#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)](/cfr/26/2010.md?p=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](/cfr/26/2056A.md) is imposed. However, the decedent's DSUE amount as redetermined in accordance with [§ 20.2010-2(c)(4)](/cfr/26/20.2010-2.md?p=c-4) may be applied to certain taxable gifts of the surviving spouse. See [§ 25.2505-2(d)(3)(i)](/cfr/26/25.2505-2.md?p=d-3-i).
    - (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)](/cfr/26/2056A.md?p=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)](/cfr/26/2010.md?p=c-2) (subject the limitations in [paragraph (a)](#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)](/cfr/26/20.2010-2.md?p=c-4) for the rules for computing the decedent's DSUE amount in the case of a qualified domestic trust.
- (d) **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](/cfr/26/6501.md) applicable to the tax shown on that return. See also [section 7602](/cfr/26/7602.md) 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. For purposes of these examinations to determine the DSUE amount, the surviving spouse is considered to have a material interest that is affected by the return information of the deceased spouse within the meaning of [section 6103(e)(3)](/cfr/26/6103.md?p=e-3).
- (e) **Availability of DSUE amount for estates of nonresidents who are not citizens.** The estate of a nonresident surviving spouse who is not a citizen of the United States at the time of such surviving spouse's death shall not take into account the DSUE amount of any deceased spouse of such surviving spouse within the meaning of [§ 20.2010-1(e)(5)](/cfr/26/20.2010-1.md?p=e-5) except to the extent allowed under any applicable treaty obligation of the United States. See [section 2102(b)(3)](/cfr/26/2102.md?p=b-3).
- (f) **Effective/applicability date.** This section applies to the estates of decedents dying on or after June 12, 2015. See [26 CFR 20.2010-3T](/cfr/26/20.2010-3T.md), as contained in [26 CFR part 20](/cfr/26/part20.md), revised as of April 1, 2015, for the rules applicable to estates of decedents dying on or after January 1, 2011, and before June 12, 2015.