(a) Scope of section 691. In general, the regulations under section 691 cover: (1) The provisions requiring that amounts which are not includible in gross income for the decedent's last taxable year or for a prior taxable year be included in the gross income of the estate or persons receiving such income to the extent that such amounts constitute “income in respect of a decedent”; (2) the taxable effect of a transfer of the right to such income; (3) the treatment of certain deductions and credit in respect of a decedent which are not allowable to the decedent for the taxable period ending with his death or for a prior taxable year; (4) the allowance to a recipient of income in respect of a decedent of a deduction for estate taxes attributable to the inclusion of the value of the right to such income in the decedent's estate; (5) special provisions with respect to installment obligations acquired from a decedent and with respect to the allowance of a deduction for estate taxes to a surviving annuitant under a joint and survivor annuity contract; and (6) special provisions relating to installment obligations transmitted at death when prior law applied to the transmission.

(b) General definition. In general, the term income in respect of a decedent refers to those amounts to which a decedent was entitled as gross income but which were not properly includible in computing his taxable income for the taxable year ending with the date of his death or for a previous taxable year under the method of accounting employed by the decedent. See the regulations under section 451. Thus, the term includes:

(1) All accrued income of a decedent who reported his income by use of the cash receipts and disbursements method;

(2) Income accrued solely by reason of the decedent's death in case of a decedent who reports his income by use of an accrual method of accounting; and

(3) Income to which the decedent had a contingent claim at the time of his death.

(c) Prior decedent. The term income in respect of a decedent also includes the amount of all items of gross income in respect of a prior decedent, if (1) the right to receive such amount was acquired by the decedent by reason of the death of the prior decedent or by bequest, devise, or inheritance from the prior decedent and if (2) the amount of gross income in respect of the prior decedent was not properly includible in computing the decedent's taxable income for the taxable year ending with the date of his death or for a previous taxable year. See example 2 of paragraph (b) of § 1.691(a)-2.

(d) Items excluded from gross income. Section 691 applies only to the amount of items of gross income in respect of a decedent, and items which are excluded from gross income under subtitle A of the Code are not within the provisions of section 691.

(e) Cross reference. For items deemed to be income in respect of a decedent for purposes of the deduction for estate taxes provided by section 691(c), see paragraph (c) of § 1.691(c)-1.