42 CFR §428.405

1. (a)Rebate amounts owed by a manufacturer. For payment of a rebate amount owed by a manufacturer:
   1. (1)Upon receipt of a rebate amount, payment is due no later than 11:59 p.m. Pacific Time (PT) on the 30th calendar day after the date of receipt of information regarding the rebate amount on—
      1. (i)A Rebate Report as set forth in § 428.401(c) or § 428.402; or
      2. (ii)A report of a reconciled rebate amount as set forth in § 428.401(d) or § 428.402.
   2. (2)Failure to pay a rebate amount due timely and in full may result in an enforcement action as described in subpart F of this part.
2. (b)Refund to the manufacturer. If a reconciled rebate amount for an applicable period as set forth in § 428.401(d) or § 428.402 is less than what the manufacturer paid for that applicable period, CMS will initiate the process to provide a refund equal to the excess amount paid within 60 days of the date of receipt of the report with such reconciled rebate amount.