20 CFR § 404.408b - Reduction of retroactive monthly social security benefits where supplemental security income (SSI) payments were received for the same period.
(a) When reduction is required. We will reduce your retroactive social security benefits if—
(1) You are entitled to monthly social security benefits for a month or months before the first month in which those benefits are paid; and
(2) SSI payments (including federally administered State supplementary payments) which were made to you for the same month or months would have been reduced or not made if your social security benefits had been paid when regularly due instead of retroactively.
(b) Amount of reduction. Your retroactive monthly social security benefits will be reduced by the amount of the SSI payments (including federally administered State supplementary payments) that would not have been paid to you, if you had received your monthly social security benefits when they were regularly due instead of retroactively.
(c) Benefits subject to reduction. The reduction described in this section applies only to monthly social security benefits. Social security benefits which we pay to you for any month after you have begun receiving recurring monthly social security benefits, and for which you did not have to file a new application, are not subject to reduction. The lump-sum death payment, which is not a monthly benefit, is not subject to reduction.
(d) Refiguring the amount of the reduction. We will refigure the amount of the reduction if there are subsequent changes affecting your claim which relate to the reduction period described in paragraph (a) of this section. Refiguring is generally required where there is a change in your month of entitlement or the amount of your social security benefits or SSI payments (including federally administered State supplementary payments) for the reduction period.
(e) Reimbursement of reduced retroactive monthly social security benefits. The amount of the reduction will be—
(1) First used to reimburse the States for the amount of any federally administered State supplementary payments that would not have been made to you if the monthly social security benefits had been paid when regularly due instead of retroactively; and
(2) The remainder, if any, shall be covered into the general fund of the U.S. Treasury for the amount of SSI benefits that would not have been paid to you if the monthly social security benefits had been paid to you when regularly due instead of retroactively.