12 CFR 226.21 - Treatment of credit balances.
When a credit balance in excess of $1 is created in connection with a transaction (through transmittal of funds to a creditor in excess of the total balance due on an account, through rebates of unearned finance charges or insurance premiums, or through amounts otherwise owed to or held for the benefit of a consumer), the creditor shall:
(a) Credit the amount of the credit balance to the consumer's account;
(b) Refund any part of the remaining credit balance, upon the written request of the consumer; and
(c) Make a good faith effort to refund to the consumer by cash, check, or money order, or credit to a deposit account of the consumer, any part of the credit balance remaining in the account for more than 6 months, except that no further action is required if the consumer's current location is not known to the creditor and cannot be traced through the consumer's last known address or telephone number.