Okla. Stat. tit. 60, § 60-175.402: Distribution from trust or estate

DISTRIBUTION FROM TRUST OR ESTATE

A trustee shall allocate to income an amount received as a

distribution of income from a trust or an estate in which the trust

has an interest other than a purchased interest, and shall allocate

to principal an amount received as a distribution of principal from

such a trust or estate. If a trustee purchases an interest in a

trust that is an investment entity, or a decedent or donor transfers

an interest in such a trust to a trustee, Section 10 or 24 of this

act applies to a receipt from the trust.