42 U.S.C. § 1320a–6

(a) Reduction in benefits Notwithstanding any other provision of this chapter, in any case where an individual— (1) is entitled to benefits under subchapter II that were not paid in the months in which they were regularly due; and (2) is an individual or eligible spouse eligible for supplemental security income benefits for one or more months in which the benefits referred to in clause (1) were regularly due, then any benefits under subchapter II that were regularly due in such month or months, or supplemental security income benefits for such month or months, which are due but have not been paid to such individual or eligible spouse shall be reduced by an amount equal to so much of the supplemental security income benefits, whether or not paid retroactively, as would not have been paid or would not be paid with respect to such individual or spouse if he had received such benefits under subchapter II in the month or months in which they were regularly due. A benefit under subchapter II shall not be reduced pursuant to the preceding sentence to the extent that any amount of such benefit would not otherwise be available for payment in full of the maximum fee which may be recovered from such benefit by an attorney pursuant to subsection (a)(4) or (b) of section 406 of this title . (b) “Supplemental security income benefits” defined For purposes of this section, the term “supplemental security income benefits” means benefits paid or payable by the Commissioner of Social Security under subchapter XVI, including State supplementary payments under an agreement pursuant to section 1382e(a) of this title or an administration agreement under section 212(b) of Public Law 93–66 . (c) Reimbursement of the State From the amount of the reduction made under subsection (a), the Commissioner of Social Security shall reimburse the State on behalf of which supplementary payments were made for the amount (if any) by which such State’s expenditures on account of such supplementary payments for the month or months involved exceeded the expenditures which the State would have made (for such month or months) if the individual had received the benefits under subchapter II at the times they were regularly due. An amount equal to the portion of such reduction remaining after reimbursement of the State under the preceding sentence shall be covered into the general fund of the Treasury.