((a)) ** Conditions for reduction; computation** If for any month prior to the month in which an individual attains retirement age (as defined in section 416()(1) of this title)—

((1)) such individual is entitled to benefits under , and

((2)) such individual is entitled for such month to—

((A)) periodic benefits on account of his or her total or partial disability (whether or not permanent) under a workmen’s compensation law or plan of the United States or a State, or

((B)) periodic benefits on account of his or her total or partial disability (whether or not permanent) under any other law or plan of the United States, a State, a political subdivision (as that term is used in ), or an instrumentality of two or more States (as that term is used in ), other than (i) benefits payable under title 38, (ii) benefits payable under a program of assistance which is based on need, (iii) benefits based on service all or substantially all of which was included under an agreement entered into by a State and the Commissioner of Social Security under , and (iv) benefits under a law or plan of the United States based on service all or substantially all of which is employment as defined in ,

((3)) such total of benefits under sections 423 and 402 of this title for such month, and

((4)) such periodic benefits payable (and actually paid) for such month to such individual under such laws or plans,

((5)) 80 per centum of his “average current earnings”, or

((6)) the total of such individual’s disability insurance benefits under for such month and of any monthly insurance benefits under for such month based on his wages and self-employment income, prior to reduction under this section.

((7)) the total of the benefits under sections 423 and 402 of this title, after reduction under this section, with respect to all persons entitled to benefits on the basis of such individual’s wages and self-employment income for such month which were determined for such individual and such persons for the first month for which reduction under this section was made (or which would have been so determined if all of them had been so entitled in such first month), and

((8)) any increase in such benefits with respect to such individual and such persons, before reduction under this section, which is made effective for months after the first month for which reduction under this section is made.

((b)) ** Reduction where benefits payable on other than monthly basis** If any periodic benefit for a total or partial disability under a law or plan described in subsection (a)(2) is payable on other than a monthly basis (excluding a benefit payable as a lump sum except to the extent that it is a commutation of, or a substitute for, periodic payments), the reduction under this section shall be made at such time or times and in such amounts as the Commissioner of Social Security finds will approximate as nearly as practicable the reduction prescribed by subsection (a).

((c)) ** Reductions and deductions under other provisions** Reduction of benefits under this section shall be made after any reduction under subsection (a) of , but before deductions under such section and under section 422(b)  of this title.section 403 of this title1

((d)) ** Exception** The reduction of benefits required by this section shall not be made if the law or plan described in subsection (a)(2) under which a periodic benefit is payable provides for the reduction thereof when anyone is entitled to benefits under this subchapter on the basis of the wages and self-employment income of an individual entitled to benefits under , and such law or plan so provided on .section 423 of this titleFebruary 18, 19811981-02-18

((e)) ** Conditions for payment** If it appears to the Commissioner of Social Security that an individual may be eligible for periodic benefits under a law or plan which would give rise to reduction under this section, the Commissioner may require, as a condition of certification for payment of any benefits under to any individual for any month and of any benefits under for such month based on such individual’s wages and self-employment income, that such individual certify (i) whether he has filed or intends to file any claim for such periodic benefits, and (ii) if he has so filed, whether there has been a decision on such claim. The Commissioner of Social Security may, in the absence of evidence to the contrary, rely upon such a certification by such individual that he has not filed and does not intend to file such a claim, or that he has so filed and no final decision thereon has been made, in certifying benefits for payment pursuant to .section 423 of this titlesection 402 of this titlesection 405(i) of this title

((f)) ** Redetermination of reduction**

((1)) In the second calendar year after the year in which reduction under this section in the total of an individual’s benefits under and any benefits under based on his wages and self-employment income was first required (in a continuous period of months), and in each third year thereafter, the Commissioner of Social Security shall redetermine the amount of such benefits which are still subject to reduction under this section; but such redetermination shall not result in any decrease in the total amount of benefits payable under this subchapter on the basis of such individual’s wages and self-employment income. Such redetermined benefit shall be determined as of, and shall become effective with, the January following the year in which such redetermination was made.

((2)) In making the redetermination required by paragraph (1), the individual’s average current earnings (as defined in subsection (a)) shall be deemed to be the product of—

((A)) his average current earnings as initially determined under subsection (a); and

((B)) the ratio of (i) the national average wage index (as defined in ) for the calendar year before the year in which such redetermination is made to (ii) the national average wage index (as so defined) for the calendar year before the year in which the reduction was first computed (but not counting any reduction made in benefits for a previous period of disability).

((g)) ** Proportionate reduction; application of excess** Whenever a reduction in the total of benefits for any month based on an individual’s wages and self-employment income is made under this section, each benefit, except the disability insurance benefit, shall first be proportionately decreased, and any excess of such reduction over the sum of all such benefits other than the disability insurance benefits shall then be applied to such disability insurance benefit.

((h)) ** Furnishing of information**

((1)) Notwithstanding any other provision of law, the head of any Federal agency shall provide such information within its possession as the Commissioner of Social Security may require for purposes of making a timely determination of the amount of the reduction, if any, required by this section in benefits payable under this subchapter, or verifying other information necessary in carrying out the provisions of this section.

((2)) The Commissioner of Social Security is authorized to enter into agreements with States, political subdivisions, and other organizations that administer a law or plan subject to the provisions of this section, in order to obtain such information as the Commissioner may require to carry out the provisions of this section.