26 U.S.C. § 677: Income for benefit of grantor

distributed to the grantor or the grantor’s spouse; held or accumulated for future distribution to the grantor or the grantor’s spouse; or applied to the payment of premiums on policies of insurance on the life of the grantor or the grantor’s spouse (except policies of insurance irrevocably payable for a purpose specified in section 170(c) (relating to definition of charitable contributions)). Income of a trust shall not be considered taxable to the grantor under subsection (a) or any other provision of this chapter merely because such income in the discretion of another person, the trustee, or the grantor acting as trustee or co-trustee, may be applied or distributed for the support or maintenance of a beneficiary (other than the grantor’s spouse) whom the grantor is legally obligated to support or maintain, except to the extent that such income is so applied or distributed. In cases where the amounts so applied or distributed are paid out of corpus or out of other than income for the taxable year, such amounts shall be considered to be an amount paid or credited within the meaning of paragraph (2) of section 661(a) and shall be taxed to the grantor under section 662.