42 CFR 433.312 - Basic requirements for refunds.
(1) Except as provided in paragraph (b) of this section, the State Medicaid agency has 1 year from the date of discovery of an overpayment to a provider to recover or seek to recover the overpayment before the Federal share must be refunded to CMS.
(2) The State Medicaid agency must refund the Federal share of overpayments at the end of the 1-year period following discovery in accordance with the requirements of this subpart, whether or not the State has recovered the overpayment from the provider.
(b)Exception. The agency is not required to refund the Federal share of an overpayment made to a provider when the State is unable to recover the overpayment amount because the provider has been determined bankrupt or out of business in accordance with § 433.318.
(2) The date upon which an overpayment occurs is the date upon which a State, using its normal method of reimbursement for a particular class of provider (e.g., check, interfund transfer), makes the payment involving unallowable costs to a provider.