Title 26 — Internal Revenue CodeRelease 119-73
§666 Accumulation distribution allocated to preceding years
Title 26 › Subtitle Subtitle A— - Income Taxes › Chapter CHAPTER 1— - NORMAL TAXES AND SURTAXES › Subchapter Subchapter J— - Estates, Trusts, Beneficiaries, and Decedents › Part PART I— - ESTATES, TRUSTS, AND BENEFICIARIES › Subpart Subpart D— - Treatment of Excess Distributions by Trusts › § 666
Summary
Treat a trust’s accumulation distribution as if parts of it were paid out on the last day of earlier taxable years, starting with the oldest year, under paragraph (2) of section 661(a). Do this only up to the amount that is more than the total undistributed net income from all earlier years. For any earlier year, the amount treated as paid cannot be more than that year’s undistributed net income. When you figure each year’s undistributed net income, do not count the accumulation distribution or any later accumulation distributions. If the part treated as paid for a prior year is at least that year’s undistributed net income, the trust is also treated as having paid an extra amount equal to the trust tax for that prior year (not including the tax under section 55) that is due to that undistributed net income. If the part treated as paid is less than the undistributed net income, the extra amount equals that tax multiplied by the ratio of the part to the undistributed net income. If records are missing, treat the amount as coming from the earliest year the trust existed when it earned undistributed net income. No refunds or credits are allowed for earlier years because of these treated distributions.
Full Legal Text
Title 26, §666
Internal Revenue Code — Source: USLM XML via OLRC
(a)In the case of a trust which is subject to subpart C, the amount of the accumulation distribution of such trust for a taxable year shall be deemed to be an amount within the meaning of paragraph (2) of section 661(a) distributed on the last day of each of the preceding taxable years, commencing with the earliest of such years, to the extent that such amount exceeds the total of any undistributed net income for all earlier preceding taxable years. The amount deemed to be distributed in any such preceding taxable year under the preceding sentence shall not exceed the undistributed net income for such preceding taxable year. For purposes of this subsection, undistributed net income for each of such preceding taxable years shall be computed without regard to such accumulation distribution and without regard to any accumulation distribution determined for any succeeding taxable year.
(b)If any portion of an accumulation distribution for any taxable year is deemed under subsection (a) to be an amount within the meaning of paragraph (2) of section 661(a) distributed on the last day of any preceding taxable year, and such portion of such distribution is not less than the undistributed net income for such preceding taxable year, the trust shall be deemed to have distributed on the last day of such preceding taxable year an additional amount within the meaning of paragraph (2) of section 661(a). Such additional amount shall be equal to the taxes (other than the tax imposed by section 55) imposed on the trust for such preceding taxable year attributable to the undistributed net income. For purposes of this subsection, the undistributed net income and the taxes imposed on the trust for such preceding taxable year attributable to such undistributed net income shall be computed without regard to such accumulation distribution and without regard to any accumulation distribution determined for any succeeding taxable year.
(c)If any portion of an accumulation distribution for any taxable year is deemed under subsection (a) to be an amount within the meaning of paragraph (2) of section 661(a) distributed on the last day of any preceding taxable year and such portion of the accumulation distribution is less than the undistributed net income for such preceding taxable year, the trust shall be deemed to have distributed on the last day of such preceding taxable year an additional amount within the meaning of paragraph (2) of section 661(a). Such additional amount shall be equal to the taxes (other than the tax imposed by section 55) imposed on the trust for such taxable year attributable to the undistributed net income multiplied by the ratio of the portion of the accumulation distribution to the undistributed net income of the trust for such year. For purposes of this subsection, the undistributed net income and the taxes imposed on the trust for such preceding taxable year attributable to such undistributed net income shall be computed without regard to the accumulation distribution and without regard to any accumulation distribution determined for any succeeding taxable year.
(d)If adequate records are not available to determine the proper application of this subpart to an amount distributed by a trust, such amount shall be deemed to be an accumulation distribution consisting of undistributed net income earned during the earliest preceding taxable year of the trust in which it can be established that the trust was in existence.
(e)No refund or credit shall be allowed to a trust or a beneficiary of such trust for any preceding taxable year by reason of a distribution deemed to have been made by such trust in such year under this section.
Legislative History
Notes & Related Subsidiaries
Editorial Notes
Amendments
1980—Subsec. (c). Pub. L. 96–222 inserted “(other than the tax imposed by section 55)” after “equal to the taxes”. 1978—Subsec. (b). Pub. L. 95–600 inserted “(other than the tax imposed by section 55)” after “equal to the taxes”. 1976—Subsec. (e). Pub. L. 94–455 added subsec. (e). 1969—Subsec. (a). Pub. L. 91–172 substituted in first sentence “In the case of a trust which is subject to subpart (C)” for “In the case of a trust (other than a foreign trust created by a United States person) which for a taxable year beginning after December 31, 1953, is subject to subpart (C)”, “for a taxable year” for “for such taxable year”, and “undistributed net income for all earlier preceding taxable years” for “undistributed net incomes for any taxable years intervening between the taxable year with respect to which the accumulation distribution is determined and such preceding taxable year” and in second sentence “for such” for “of such”, inserted in first sentence “, commencing with the earliest of such years,” after “preceding taxable years”, struck out “5” before “preceding taxable years” in first and third sentences and last sentence which read as follows: “In the case of a foreign trust created by a United States person, this subsection shall apply to the preceding taxable years of the trust without regard to any provision of the preceding sentences which would (but for this sentence) limit its application to the 5 preceding taxable years.” Subsec. (b). Pub. L. 91–172 inserted “attributable to the undistributed net income” after “taxable year” in second sentence and “attributable to such undistributed net income” before “shall be computed” in third sentence. Subsec. (c). Pub. L. 91–172 inserted “attributable to the undistributed net income” before “multiplied by the ratio” in second sentence and “attributable to such undistributed net income” before “shall be computed” in third sentence. Subsec. (d). Pub. L. 91–172 added subsec. (d). 1962—Subsec. (a). Pub. L. 87–834 inserted “(other than a foreign trust created by a United States person)” after “In the case of a trust”, and inserted sentence making this subsection applicable, in the case of a foreign trust created by a United States person, to the preceding taxable years of the trust without regard to any provision of the preceding sentences of this subsection which would (but for this sentence) limit its application to the 5 preceding taxable years.
Statutory Notes and Related Subsidiaries
Effective Date
of 1980 AmendmentAmendment by Pub. L. 96–222 effective, except as otherwise provided, as if it had been included in the provisions of the Revenue Act of 1978, Pub. L. 95–600, to which such amendment relates, see section 201 of Pub. L. 96–222, set out as a note under section 32 of this title.
Effective Date
of 1978 AmendmentAmendment by Pub. L. 95–600 applicable to taxable years beginning after Dec. 31, 1978, see section 421(g) of Pub. L. 95–600, set out as a note under section 5 of this title.
Effective Date
of 1976 AmendmentAmendment by Pub. L. 94–455 applicable to distributions made in taxable years beginning after Dec. 31, 1975, see section 701(h) of Pub. L. 94–455, set out as a note under section 667 of this title.
Effective Date
of 1969 AmendmentAmendment by Pub. L. 91–172 applicable to taxable years beginning after Dec. 31, 1968, except that for taxable years of a trust beginning before Jan. 1, 1970, first sentence of subsec. (a) not applicable and amount of accumulation distribution stated, see section 331(d)(1), (2)(B) of Pub. L. 91–172, set out as a note under section 665 of this title.
Effective Date
of 1962 AmendmentAmendment by Pub. L. 87–834 applicable with respect to distributions made after Dec. 31, 1962, see section 7(j) of Pub. L. 87–834, set out as a note under section 643 of this title.
Reference
Citations & Metadata
Citation
26 U.S.C. § 666
Title 26 — Internal Revenue Code
Last Updated
Apr 6, 2026
Release point: 119-73