§8133. Apportionment when income interest ends.

(a) End of mandatory income interest.--When a mandatory income interest ends, the trustee shall pay to a mandatory income beneficiary who survives that date, or the estate of a deceased mandatory income beneficiary whose death causes the interest to end, the beneficiary's share of the undistributed income which is not disposed of under the governing instrument unless the beneficiary has an unqualified power to revoke more than 5% of the trust immediately before the income interest ends. In the latter case, the undistributed income from the portion of the trust that may be revoked shall be added to principal.

(b) Proration of final payment.--When a trustee's obligation to pay a fixed annuity or a fixed fraction of the value of the trust's assets ends, the trustee shall prorate the final payment if and to the extent required by applicable law to accomplish a purpose of the trust or its settlor or testator relating to income, gift, estate or other tax requirements.

(c) Definition.--As used in this section, the term "undistributed income" means net income received before the date on which an income interest ends. The term does not include an item of income or expense which is due or accrued or net income which has been added or is required to be added to principal under the governing instrument.