Okla. Stat. tit. 60, § 60-175.303: Apportionment when income interest ends

APPORTIONMENT WHEN INCOME INTEREST ENDS

A. In this section, "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 that is due or accrued

or net income that has been added or is required to be added to

principal under the terms of the trust.

B. 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 that is not disposed of under the terms of the trust unless

the beneficiary has an unqualified power to revoke more than five

percent (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 must be added to principal.

C. 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

relating to income, gift, estate, or other tax requirements.