If an amount specified in section 662(a) (1) or (2) is paid, credited, or required to be distributed by an estate or trust for a taxable year which does not end with or within the last taxable year of a beneficiary (because of the beneficiary's death), the extent to which the amount is included in the gross income of the beneficiary for his last taxable year or in the gross income of his estate is determined by the computations under section 662 for the taxable year of the estate or trust in which his last taxable year ends. Thus, the distributable net income and the amounts paid, credited, or required to be distributed for the taxable year of the estate or trust, determine the extent to which the amounts paid, credited, or required to be distributed to the beneficiary are included in his gross income for his last taxable year or in the gross income of his estate. (Section 662(c) does not apply to such amounts.) The gross income for the last taxable year of a beneficiary on the cash basis includes only income actually distributed to the beneficiary before his death. Income required to be distributed, but in fact distributed to his estate, is included in the gross income of the estate as income in respect of a decedent under section 691. See paragraph (e) of § 1.663(c)-3 with respect to separate share treatment for the periods before and after the death of a trust's beneficiary.