(a)

(1) Notwithstanding any other provision of this subchapter, if an individual under section 8402(b)(2) is entitled, or would on proper application be entitled, to old-age insurance benefits under title II of the Social Security Act, the annuity otherwise payable to such individual shall be reduced under this subsection.

(2) A reduction under this subsection commences beginning with the first month for which the individual both—

(A) is entitled to an annuity under this subchapter; and

(B) is entitled, or would on proper application be entitled, to old-age insurance benefits under title II of the Social Security Act.

(3)

(A)

(i) Subject to clause (ii) and subparagraphs (B) and (C), the amount of a reduction under this subsection shall be equal to the difference between—

(I) the old-age insurance benefit which would be payable to the individual for the month referred to in paragraph (2); and

(II) the old-age insurance benefit which would be so payable, excluding all wages derived from Federal service of the individual, and assuming the individual were fully insured (as defined by section 214(a) of the Social Security Act).

(ii) For purposes of this subsection, the amount of a benefit referred to in subclause (I) or (II) of clause (i) shall be determined without regard to subsections (b) through (l) of section 203 of the Social Security Act, and without regard to the requirement that an application for such benefit be filed.

(B) A reduction under this subsection—

(i) may not exceed an amount equal to the product of—

(I) the old-age insurance benefit to which the individual is entitled (or would on proper application be entitled) for the month referred to in paragraph (2), determined without regard to subsections (b) through (l) of section 203 of the Social Security Act; and

(II) a fraction, as determined under section 8421(b)(3) with respect to the individual, except that the reference to "service" in subparagraph (A) of such section shall be considered to mean Federal service; and

(ii) may not cause the annuity payment for an individual to be reduced below zero.

(C) An amount computed under subclause (I) or (II) of subparagraph (A)(i), or under subparagraph (B)(i)(I), for purposes of determining the amount of a reduction under this subsection shall be adjusted under section 8340 of this title.

(4) A reduction under this subsection applies with respect to the annuity otherwise payable to such individual under this subchapter (other than under section 8337) for the month involved—

(A) based on service of such individual; and

(B) without regard to section 8345(j), if otherwise applicable.

(5) The operation of the preceding paragraphs of this subsection shall not be considered for purposes of applying the provisions of the second sentence of section 215(a)(7)(B)(i) or the provisions of section 215(d)(5)(ii) of the Social Security Act in determining any amount under subclause (I) or (II) of paragraph (3)(A)(i) or paragraph (3)(B)(i)(I) for purposes of this subsection.

(b)

(1) Notwithstanding any other provision of this subchapter—

(A) a disability annuity to which an individual described in section 8402(b)(2) is entitled under this subchapter, and

(B) a survivor annuity to which a person is entitled under this subchapter based on the service of an individual described in section 8402(b)(2),

shall be subject to reduction under this subsection if that individual or person is also entitled (or would on proper application also be entitled) to any similar benefits under title II of the Social Security Act based on the wages and self-employment income of such individual described in section 8402(b)(2).

(2)

(A) Subject to subparagraph (B), reductions under this subsection shall be made in a manner consistent with the manner in which reductions under subsection (a) are computed and otherwise made.

(B) Reductions under this subsection shall be discontinued if, or for so long as, entitlement to the similar benefits under title II of the Social Security Act (as referred to in paragraph (1)) is terminated (or, in the case of an individual who has not made proper application therefor, would be terminated).

(3) For the purpose of applying section 224 of the Social Security Act to the disability insurance benefit used to compute the reduction under this subsection, the amount of the CSRS annuity considered shall be the amount of the CSRS annuity before application of this section.

(4) The Office shall prescribe regulations to carry out this subsection.

(c) For the purpose of this section, the term "Federal service" means service which is employment for the purposes of title II of the Social Security Act and chapter 21 of the Internal Revenue Code of 1986 by reason of the amendments made by section 101 of the Social Security Amendments of 1983.

(d) In administering subsections (a) through (c)—

(1) the terms "an individual under section 8402(b)(2)" and "an individual described in section 8402(b)(2)" shall each be considered to include any individual—

(A) who is subject to this subchapter as a result of any provision of law described in section 8347(o), and

(B) whose employment (as described in section 8347(o)) is also employment for purposes of title II of the Social Security Act and chapter 21 of the Internal Revenue Code of 1986; and

(2) the term "Federal service", as applied with respect to any individual to whom this section applies as a result of paragraph (1), means any employment referred to in paragraph (1)(B) performed after December 31, 1983.