§ 2001.
(b)
Computation of tax
The tax imposed by this section shall be the amount equal to the excess (if any) of—
(1)
a tentative tax computed under subsection (c) on the sum of—
(A)
the amount of the taxable estate, and
(B)
the amount of the adjusted taxable gifts, over
(2)
the aggregate amount of tax which would have been payable under chapter 12 with respect to gifts made by the decedent after December 31, 1976, if the modifications described in subsection (g) had been applicable at the time of such gifts.
For purposes of paragraph (1)(B), the term “adjusted taxable gifts” means the total amount of the taxable gifts (within the meaning of section 2503) made by the decedent after December 31, 1976, other than gifts which are includible in the gross estate of the decedent.
(d)
Adjustment for gift tax paid by spouse
For purposes of subsection (b)(2), if—
(1)
the decedent was the donor of any gift one-half of which was considered under section 2513 as made by the decedent’s spouse, and
(2)
the amount of such gift is includible in the gross estate of the decedent,
any tax payable by the spouse under chapter 12 on such gift (as determined under section 2012(d)) shall be treated as a tax payable with respect to a gift made by the decedent.
(g)
Modifications to tax payable
(1)
Modifications to gift tax payable to reflect different tax rates
For purposes of applying subsection (b)(2) with respect to 1 or more gifts, the rates of tax under subsection (c) in effect at the decedent’s death shall, in lieu of the rates of tax in effect at the time of such gifts, be used both to compute—
(A)
the tax imposed by chapter 12 with respect to such gifts, and
(B)
the credit allowed against such tax under section 2505, including in computing—
(i)
the applicable credit amount under section 2505(a)(1), and
(ii)
the sum of the amounts allowed as a credit for all preceding periods under section 2505(a)(2).
(2)
Modifications to estate tax payable to reflect different basic exclusion amounts
The Secretary shall prescribe such regulations as may be necessary or appropriate to carry out this section with respect to any difference between—
(A)
the basic exclusion amount under section 2010(c)(3) applicable at the time of the decedent’s death, and
(B)
the basic exclusion amount under such section applicable with respect to any gifts made by the decedent.
([Aug. 16, 1954, ch. 736], [68A Stat. 373]; [Pub. L. 94–455, title XX, § 2001(a)(1)], Oct. 4, 1976, [90 Stat. 1846]; [Pub. L. 95–600, title VII, § 702(h)(1)], Nov. 6, 1978, [92 Stat. 2930]; [Pub. L. 97–34, title IV, § 402(a)]–(c), Aug. 13, 1981, [95 Stat. 300]; [Pub. L. 98–369, div. A, title I, § 21(a)], July 18, 1984, [98 Stat. 506]; [Pub. L. 100–203, title X, § 10401(a)]–(b)(2)(A), Dec. 22, 1987, [101 Stat. 1330–430], 1330–431; [Pub. L. 103–66, title XIII, § 13208(a)]–(b)(2), Aug. 10, 1993, [107 Stat. 469]; [Pub. L. 105–34, title V], §§ 501(a)(1)(D), 506(a), Aug. 5, 1997, [111 Stat. 845], 855; [Pub. L. 105–206, title VI, § 6007(e)(2)(B)], July 22, 1998, [112 Stat. 810]; [Pub. L. 105–277, div. J, title IV, § 4003(c)], Oct. 21, 1998, [112 Stat. 2681–909]; [Pub. L. 107–16, title V, § 511(a)]–(c), June 7, 2001, [115 Stat. 70]; [Pub. L. 111–312, title III, § 302(a)(2)], (d)(1), Dec. 17, 2010, [124 Stat. 3301], 3302;