(a) Manner of computing tax. If a beneficiary has elected under section 669(a) to compute the tax on the amounts deemed distributed under section 666 by the short-cut throwback method provided in section 669(a)(1)(B), the tax liability of the beneficiary for the taxable year is computed in the following manner:

(1) First, determine the number of preceding taxable years of the trust, on the last day of which an amount is deemed under section 666(a) to have been distributed. In any case where there has been a prior accumulation distribution with respect to which the beneficiary has elected to compute his tax either by the exact throwback method or by the short-cut throwback method, or to which the next to the last sentence of section 668(a) has applied, for purposes of an election to use the short-cut throwback method with respect to a subsequent accumulation distribution, in determining the number of preceding taxable years of the trust with respect to which an amount of the subsequent accumulation distribution is deemed distributed to a beneficiary under section 666(a), there shall be excluded any preceding taxable year during which any part of the prior accumulation distribution was deemed distributed to the beneficiary. For example, assume that an accumulation distribution of $90,000 made to a beneficiary in 1963 is deemed distributed in the amounts of $25,000 in each of the years 1962, 1961, and 1960, and in the amount of $15,000 in 1959, and a subsequent accumulation distribution of $85,000 made to the same beneficiary in 1964 is deemed distributed in the amount of $10,000 during 1959, and $25,000 during each of the years 1958, 1957, and 1956. The accumulation distribution made in 1963 is deemed distributed in 4 preceding taxable years of the trust (1962, 1961, 1960, and 1959). Inasmuch as the year 1959 was a year during which part of the 1963 accumulation distribution was deemed distributed, for purposes of determining the number of preceding taxable years in which the accumulation distribution of $85,000 made in 1964 is deemed distributed, the year 1959 is excluded and the $85,000 accumulation distribution is deemed distributed in three preceding taxable years (1958, 1957, and 1956),

(2) Second, divide the number of preceding taxable years of the trust, on the last day of which an amount is deemed under section 666(a) to have been distributed (determined as provided in subparagraph (1) of this paragraph) into the amount (representing an accumulation distribution made by a foreign trust created by a U.S. person) required to be included under section 669(a) in the gross income of the beneficiary for the taxable year,

(3) Third, compute the tax of the beneficiary for the current taxable year (the year in which the accumulation distribution is paid, credited, or required to be distributed to him) and for each of the 2 taxable years immediately preceding such year,

(i) With the inclusion in gross income of the beneficiary for each of such 3 years of the amount determined under subparagraph (2) of this paragraph, and

(ii) Without such inclusion.

The difference between the amount of tax computed under subdivision (i) of this subparagraph for each year and the amount computed under subdivision (ii) of this subparagraph for that year is the additional tax resulting from the inclusion in gross income for that year of the amount determined under subparagraph (2) of this paragraph. If the number of preceding taxable years of the trust, on the last day of which an amount is deemed under section 666(a) to have been distributed, is less than three, the taxable years of the beneficiary for which this recomputation is made shall equal the number of years in which an amount is deemed under section 666(a) to have been distributed, commencing with the taxable year of the beneficiary in which the accumulation distribution is paid, credited, or required to be distributed to him. If the beneficiary was not alive during one of the two taxable years immediately preceding the taxable year, the tax resulting from the inclusion of the amount determined in subparagraph (2) of this paragraph in the gross income of the beneficiary will be computed only for the taxable year in which the accumulation distribution was paid, credited, or required to be distributed to him and the preceding year during which the beneficiary was alive. In the event the beneficiary was not alive during either of the 2 years immediately preceding the taxable year in which the accumulation distribution was paid, credited, or required to be distributed, the tax shall be computed on the basis of the beneficiary's taxable year without regard to the inclusion in income required by section 668(a) of any amount other than pursuant to section 669(a)(1)(B). For example, assume that a foreign trust created by a U.S. person accumulates $3,000 of income in 1964 and $7,000 in 1963 and then distributes the accumulated income on January 1, 1965, to a beneficiary who is a U.S. person. The limitation on tax is determined by recomputing the beneficiary's gross income for 1964 and 1965 by adding $5,000 to his gross income for each year. If the same distribution were made to an infant who was born in 1965, the limitation on tax would be computed by adding $5,000 to his gross income for such year. In the case of the infant, the resulting increase in tax would be multiplied by two to arrive at the limitation on the increase in his tax for 1965 attributable to such distribution.

(4) Fourth, add the additional taxes resulting from the application of subparagraph (3) of this paragraph for the taxable year and the 2 taxable years (or the 1 taxable year, where applicable) immediately preceding the year in which the accumulation distribution is paid, credited, or required to be distributed and then divide this amount by three (or two, where applicable). The resulting amount is then multiplied by the number of preceding taxable years of the trust on the last day of which an amount is deemed under section 666(a) to have been distributed (previously determined under subparagraph (1) of this paragraph). The resulting amount is the tax, under the short-cut throwback method provided in section 669(a)(1)(B), which is attributable to the amounts treated under section 668(a) as having been received by the beneficiary from a foreign trust created by a U.S. person on the last day of the preceding taxable year.

(5) Fifth, add the amount determined under subparagraph (4) of this paragraph to the beneficiary's tax for the taxable year in which the accumulation distribution was paid, credited, or required to be distributed to him, computed without inclusion of the accumulation distribution in gross income for that year. The total is the beneficiary's income tax for such year.

(b) Credit for tax paid by trust. The income taxes deemed distributed to a beneficiary in the manner described in paragraphs (c) and (d) of §1.669(a)-2 are included in the beneficiary's gross income for purposes of the computations required by this section. To the extent provided in §1.669(a)-2, credits for such taxes are allowable to the beneficiary. In the computations under the short-cut throwback method provided in section 669(a)(1)(B), the rules set forth in section 662(b) and §1.662(b)-1 shall be applied in determining the character, in the hands of the beneficiary, of the amounts, including taxes includible in the distribution or deemed distributed, treated as received by a beneficiary in prior taxable years. For example, if one-fifth of such amounts represents tax-free income, then one-fifth of the amount determined under paragraph (a)(2) of this section shall be treated as tax-free income.

[T.D. 6989, 34 FR 739, Jan. 17, 1969]