(a) Section 677(b) provides that a grantor is not treated as the owner of a trust merely because its income may in the discretion of any person other than the grantor (except when he is acting as trustee or cotrustee) be applied or distributed for the support or maintenance of a beneficiary (other than the grantor's spouse in the case of income from property transferred in trust after October 9, 1969), such as the child of the grantor, whom the grantor or his spouse is legally obligated to support. If income of the current year of the trust is actually so applied or distributed the grantor may be treated as the owner of any portion of the trust under section 677 to that extent, even though it might have been applied or distributed for other purposes. In the case of property transferred to a trust before October 10, 1969, for the benefit of the grantor's spouse, the grantor may be treated as the owner to the extent income of the current year is actually applied for the support or maintenance of his spouse.

(b) If any amount applied or distributed for the support of a beneficiary, including the grantor's spouse in the case of property transferred in trust before October 10, 1969, whom the grantor is legally obligated to support is paid out of corpus or out of income other than income of the current year, the grantor is treated as a beneficiary of the trust, and the amount applied or distributed is considered to be an amount paid within the meaning of section 661(a)(2), taxable to the grantor under section 662. Thus, he is subject to the other relevant portions of subparts A through D (section 641 and following), part I, subchapter J, chapter 1 of the Code. Accordingly, the grantor may be taxed on an accumulation distribution or a capital gain distribution under subpart D (section 665 and following) of such part I. Those provisions are applied on the basis that the grantor is the beneficiary.

(c) For the purpose of determining the items of income, deduction, and credit of a trust to be included under this section in computing the grantor's tax liability, the income of the trust for the taxable year of distribution will be deemed to have been first distributed. For example, in the case of a trust reporting on the calendar year basis, a distribution made on January 1, 1956, will be deemed to have been made out of ordinary income of the trust for the calendar year 1956 to the extent of the income for that year even though the trust had received no income as of January 1, 1956. Thus, if a distribution of $10,000 is made on January 1, 1956, for the support of the grantor's dependent, the grantor will be treated as the owner of the trust for 1956 to that extent. If the trust received dividends of $5,000 and incurred expenses of $1,000 during that year but subsequent to January 1, he will take into account dividends of $5,000 and expenses of $1,000 in computing his tax liability for 1956. In addition, the grantor will be treated as a beneficiary of the trust with respect to the $6,000 ($10,000 less distributable income of $4,000 (dividends of $5,000 less expenses of $1,000)) paid out of corpus or out of other than income of the current year. See paragraph (b) of this section.

(d) The exception provided in section 677(b) relates solely to the satisfaction of the grantor's legal obligation to support or maintain a beneficiary. Consequently, the general rule of section 677(a) is applicable when in the discretion of the grantor or nonadverse parties income of a trust may be applied in discharge of a grantor's obligations other than his obligation of support or maintenance falling within section 677(b). Thus, if the grantor creates a trust the income of which may in the discretion of a nonadverse party be applied in the payment of the grantor's debts, such as the payment of his rent or other household expenses, he is treated as an owner of the trust regardless of whether the income is actually so applied.

(e) The general rule of section 677(a), and not section 677(b), is applicable if discretion to apply or distribute income of a trust rests solely in the grantor, or in the grantor in conjunction with other persons, unless in either case the grantor has such discretion as trustee or cotrustee.

(f) The general rule of section 677(a), and not section 677(b), is applicable to the extent that income is required, without any discretionary determination, to be applied to the support of a beneficiary whom the grantor is legally obligated to support.