26 CFR § 1.666(b)-1A - Total taxes deemed distributed.
(a) If an accumulation distribution is deemed under § 1.666(a)–1A to be distributed on the last day of a preceding taxable year and the amount is not less than the undistributed net income for such preceding taxable year, then an additional amount equal to the “taxes imposed on the trust attributable to the undistributed net income” (as defined in § 1.665(d)–1A(b)) for such preceding taxable year is also deemed distributed under section 661(a)(2). For example, a trust has undistributed net income of $8,000 for the taxable year 1974. The taxes imposed on the trust attributable to the undistributed net income are $3,032. During the taxable year 1977, an accumulation distribution of $8,000 is made to the beneficiary, which is deemed under § 1.666(a)–1A to have been distributed on the last day of 1974. The 1977 accumulation distribution is not less than the 1974 undistributed net income. Accordingly, the taxes of $3,032 imposed on the trust attributable to the undistributed net income for 1974 are also deemed to have been distributed on the last day of 1974. Thus, a total of $11,032 will be deemed to have been distributed on the last day of 1974.
(b) For the purpose of paragraph (a) of this section, the undistributed net income of any preceding taxable year and the taxes imposed on the trust for such preceding taxable year attributable to such undistributed net income are computed after taking into account any accumulation distributions of taxable years intervening between such preceding taxable year and the taxable year. See paragraph (d) of § 1.666(a)–1A.