1969—Subsec. (a). Pub. L. 91–172, § 121(d)(2)(B), substituted reference to certain property acquired with borrowed funds for reference to certain leases.

Subsec. (b). Pub. L. 91–172, § 101(j)(18), (19), redesignated subsec. (d) as (b) and substituted “sections 518 (d) and 4948 (c)(4)” for “section 503 (e)”. Former subsec. (b), dealing generally with the operation of trusts, was struck out.

Subsec. (c). Pub. L. 91–172, § 101(j)(18), struck out subsec. (c) dealing with accumulated income.

Subsec. (d). Pub. L. 91–172, § 101(j)(19), redesignated subsec. (d) as (b).

1968—Subsec. (c). Pub. L. 90–630 inserted provision that par. (1) does not apply to income attributable to property transferred to a trust before January 1, 1951, by the creator thereof if the trust was irrevocable on such date and if the income is required to be accumulated pursuant to the mandatory terms of the instrument creating the trust.

Amendment by section 101(j)(18), (19) of Pub. L. 91–172 effective Jan. 1, 1970, see section 101(k)(1) of Pub. L. 91–172, set out as an Effective Date note under section 4940 of this title.

Amendment by section 121(d)(2)(B) of Pub. L. 91–172 applicable to taxable years beginning after Dec. 31, 1969, see section 121(g) of Pub. L. 91–172, set out as a note under section 511 of this title.

Section 6(c) of Pub. L. 90–630 provided that: “The amendments made by subsection (a) [amending section 504 of this title] and (b) [amending this section] shall apply with respect to taxable years beginning after December 31, 1953, and ending after August 16, 1954. For purposes of sections 3814 and 162(g)(4) of the Internal Revenue Code of 1939, provisions having the same effect as such amendments shall be treated as included in such sections effective with respect to taxable years beginning after December 31, 1950.”