§ 2505.
(a)
General rule
In the case of a citizen or resident of the United States, there shall be allowed as a credit against the tax imposed by section 2501 for each calendar year an amount equal to—
(1)
the applicable credit amount in effect under section 2010(c) which would apply if the donor died as of the end of the calendar year, reduced by
(2)
the sum of the amounts allowable as a credit to the individual under this section for all preceding calendar periods.
For purposes of applying paragraph (2) for any calendar year, the rates of tax in effect under section 2502(a)(2) for such calendar year shall, in lieu of the rates of tax in effect for preceding calendar periods, be used in determining the amounts allowable as a credit under this section for all preceding calendar periods.
(Added [Pub. L. 94–455, title XX, § 2001(b)(2)], Oct. 4, 1976, [90 Stat. 1849]; amended [Pub. L. 97–34, title IV], §§ 401(b), 442(a)(5), Aug. 13, 1981, [95 Stat. 299], 321; [Pub. L. 101–508, title XI, § 11801(a)(40)], (c)(19)(B), Nov. 5, 1990, [104 Stat. 1388–521], 1388–528; [Pub. L. 105–34, title V, § 501(a)(2)], Aug. 5, 1997, [111 Stat. 845]; [Pub. L. 107–16, title V, § 521(b)], June 7, 2001, [115 Stat. 71]; [Pub. L. 111–312, title III], §§ 301(b), 302(b)(1)(A), (d)(2), 303(b)(1), Dec. 17, 2010, [124 Stat. 3300–3303].)