§ 4963.
(e)
Correction period
For purposes of this subchapter—
(1)
In general
The term “correction period” means, with respect to any taxable event, the period beginning on the date on which such event occurs and ending 90 days after the date of mailing under section 6212 of a notice of deficiency with respect to the second tier tax imposed on such taxable event, extended by—
(A)
any period in which a deficiency cannot be assessed under section 6213(a) (determined without regard to the last sentence of section 4961(b)), and
(B)
any other period which the Secretary determines is reasonable and necessary to bring about correction of the taxable event.
(2)
Special rules for when taxable event occurs
For purposes of paragraph (1), the taxable event shall be treated as occurring—
(A)
in the case of section 4942, on the first day of the taxable year for which there was a failure to distribute income,
(B)
in the case of section 4943, on the first day on which there are excess business holdings,
(C)
in the case of section 4971, on the last day of the plan year in which there is an accumulated funding deficiency, and
(D)
in any other case, the date on which such event occurred.
(Added [Pub. L. 96–596, § 2(c)(1)], Dec. 24, 1980, [94 Stat. 3473], § 4962; renumbered § 4963, [Pub. L. 98–369, div. A, title III, § 305(a)], July 18, 1984, [98 Stat. 783]; amended [Pub. L. 100–203, title X, § 10712(b)(3)], Dec. 22, 1987, [101 Stat. 1330–467]; [Pub. L. 104–168, title XIII, § 1311(c)(2)], July 30, 1996, [110 Stat. 1478]; [Pub. L. 109–280, title XII, § 1231(b)(1)],