§ 2021.
(d)
Offset for social security taxes
(1)
Persons covered
In the case of a participant who was a participant subject to this subchapter before January 1, 1984, and whose service—
(A)
is employment for the purposes of title II of the Social Security Act [
42 U.S.C. 401 et seq.] and chapter 21 of title 26, and
(B)
is not creditable service for any purpose under subchapter III of this chapter or chapter 84 of title 5,
there shall be deducted and withheld from the basic pay of the participant under this section during any pay period only the amount computed under paragraph (2).
(2)
Reduction in contribution
The amount deducted and withheld from the basic pay of a participant during any pay period pursuant to paragraph (1) shall be the excess of—
(A)
the amount determined by multiplying the percent applicable to the participant under subsection (a) by the basic pay payable to the participant for that pay period, over
(B)
the amount of the taxes deducted and withheld from such basic pay under
section 3101(a) of title 26 (relating to old-age, survivors, and disability insurance) for that pay period.
([Pub. L. 88–643, title II, § 211], as added [Pub. L. 102–496, title VIII, § 802], Oct. 24, 1992, [106 Stat. 3202]; amended [Pub. L. 103–178, title II, § 202(a)(3)], Dec. 3, 1993, [107 Stat. 2026]; [Pub. L. 112–96, title V, § 5003], Feb. 22, 2012, [126 Stat. 200]; [Pub. L. 118–31, div. G, title IX, § 7901(d)(1)], Dec. 22, 2023, [137 Stat. 1106].)