For purposes of paragraph (1), the taxable income of the beneficiary for any taxable year shall be deemed to be not less than zero.
For purposes of paragraph (1), if the amount of the undistributed net income deemed distributed in any preceding taxable year of the trust is less than 25 percent of the amount of the accumulation distribution divided by the number of preceding taxable years to which the accumulation distribution is allocated under section 666(a), the number of preceding taxable years of the trust with respect to which an amount is deemed distributed to a beneficiary under section 666(a) shall be determined without regard to such year.
In computing the partial tax under paragraph (1) for any beneficiary, the income of such beneficiary for each of his prior taxable years shall include amounts previously deemed distributed to such beneficiary in such year under section 666 as a result of prior accumulation distributions (whether from the same or another trust).
In the case of accumulation distributions made from more than one trust which are includible in the income of a beneficiary in the same taxable year, the distributions shall be deemed to have been made consecutively in whichever order the beneficiary shall determine.
For purposes of this paragraph, the term “partial tax” means the partial tax imposed by subsection (a)(2) determined under this subsection without regard to this paragraph.
For purposes of this paragraph, the pre-death portion of the partial tax shall be an amount which bears the same ratio to the partial tax as the portion of the accumulation distribution which is attributable to the period before the date of the death of the decedent or the date of the generation-skipping transfer bears to the total accumulation distribution.
If, in the same prior taxable year of the beneficiary in which any part of the accumulation distribution from a trust (hereinafter in this paragraph referred to as “third trust”) is deemed under section 666(a) to have been distributed to such beneficiary, some part of prior distributions by each of 2 or more other trusts is deemed under section 666(a) to have been distributed to such beneficiary, then subsections (b) and (c) of section 666 shall not apply with respect to such part of the accumulation distribution from such third trust.
For purposes of paragraph (1), an accumulation distribution from a trust to a beneficiary shall be taken into account only if such distribution, when added to any prior accumulation distributions from such trust which are deemed under section 666(a) to have been distributed to such beneficiary for the same prior taxable year of the beneficiary, equals or exceeds $1,000.
In determining the increase in tax under subsection (b)(1)(D) for any computation year, the taxes described in section 665(d)(2) which are deemed distributed under section 666(b) or (c) and added under subsection (b)(1)(C) to the taxable income of the beneficiary for any computation year shall, except as provided in subparagraphs (B) and (C), be treated as a credit against the increase in tax for such computation year under subsection (b)(1)(D).
If the beneficiary did not choose the benefits of subpart A of part III of subchapter N with respect to the computation year, the beneficiary may in lieu of treating the amounts described in subparagraph (A) (without regard to subparagraph (C)) as a credit may treat such amounts as a deduction in computing the beneficiary’s taxable income under subsection (b)(1)(C) for the computation year.
For purposes of determining under subparagraph (A) the amount treated as a credit for any computation year, the limitations under subpart A of part III of subchapter N shall be applied separately with respect to amounts added under subsection (b)(1)(C) to the taxable income of the beneficiary for such computation year. For purposes of computing the increase in tax under subsection (b)(1)(D) for any computation year for which the beneficiary did not choose the benefits of subpart A of part III of subchapter N, the beneficiary shall be treated as having chosen such benefits for such computation year.
The items of income, deduction, and credit of the Trust shall retain their character (subject to the application of section 904(f)(5)) to the extent necessary to apply this paragraph.
For purposes of this paragraph, the term “computation year” means any of the three taxable years remaining after application of subsection (b)(1)(B).
In the case of a distribution from a trust to a nonresident alien individual or to a foreign corporation, the first sentence of subsection (a) shall be applied as if the reference to the determination of character under section 662(b) applied to all amounts instead of just to tax-exempt interest.