1970—Subsec. (a)(3). Pub. L. 91–614, § 101(d)(2), substituted “fiduciary” for “executor” in heading and text.

Subsec. (b). Pub. L. 91–614, § 102(d)(7), substituted “period for which the return was filed” for “calendar year”.

1966—Subsec. (a)(1). Pub. L. 89–719 inserted “, or becomes unenforceable by reason of lapse of time,” after “sooner paid in full” and substituted “10 years from the date of death” for “10 years upon the gross estate of the decedent”.

Subsec. (a)(2). Pub. L. 89–719 substituted “person in possession, or beneficiary, to a purchaser or holder of a security interest” for “person in possession of property by reason of the exercise, nonexercise, or release of a power of appointment, or beneficiary, to a bona fide purchaser, mortgagee, or pledgee, for an adequate and full consideration in money and money’s worth” and “except any part transferred to a purchaser or a holder of a security interest” for “except any part transferred to a bona fide purchaser, mortgagee, or pledgee for an adequate and full consideration in money or money’s worth”.

Subsec. (a)(3). Pub. L. 89–719 substituted “purchaser or a holder of a security interest” for “bona fide purchaser, mortgagee, or pledgee for an adequate and full consideration in money or money’s worth” and “purchaser or holder of a security interest” for “purchaser, mortgagee, or pledgee”.

Subsec. (b). Pub. L. 89–719 substituted reference to exception provided in subsec. (c) for reference to exceptions provided in subsecs. (c) and (d), inserted reference to tax becoming unenforceable by reason of lapse of time, and substituted “purchaser or holder of a security interest” for “bona-fide purchaser, mortgagee, or pledgee, for an adequate and full consideration in money or money’s worth”.

Subsec. (c). Pub. L. 89–719 redesignated as par. (1) provisions formerly constituting subsec. (c), substituted “valid as against a mechanic’s lienor and, subject to the conditions provided by section 6323(b) (relating to protection for certain interests even though noticed filed), shall not be valid with respect to any lien or interest described in section 6323(b)” for “valid with respect to a security, as defined in section 6323(c)(2), as against any mortgagee, pledgee, or purchaser of any such security, for an adequate and full consideration in money or money’s worth, if at the time of such mortgage, pledge, or purchase such mortgagee, pledgee, or purchaser is without notice or knowledge of the existence of such lien”, and added par. (2).

Subsec. (d). Pub. L. 89–719 struck out subsec. (d) dealing with exceptions in the case of motor vehicles. See subsec. (c) above and reference therein to section 6323(b).

1964—Subsecs. (a), (b). Pub. L. 88–272, § 236(c)(2), inserted “and subsection (d) (relating to purchases of motor vehicles)”.

Subsec. (d). Pub. L. 88–272, § 236(b), added subsec. (d).

Amendment by section 101(d)(2) of Pub. L. 91–614 applicable with respect to decedents dying after Dec. 31, 1970, see section 101(j) of Pub. L. 91–614, set out as a note under section 2032 of this title.

Amendment by section 102(d)(7) of Pub. L. 91–614 applicable with respect to gifts made after Dec. 31, 1970, see section 102(e) of Pub. L. 91–614, set out as a note under section 2501 of this title.

Amendment by Pub. L. 89–719 applicable after Nov. 2, 1966, regardless of when title or lien of United States arose or when lien or interest of another person was acquired, with certain exceptions, see section 114(a)–(c) of Pub. L. 89–719, set out as a note under section 6323 of this title.

Amendment by Pub. L. 88–272 applicable to purchases made after Feb. 26, 1964, see section 236(d) of Pub. L. 88–272, set out as a note under section 6323 of this title.