12 C.F.R. § 1026.5
(a) Form of disclosures—(1) General.
(ii) The creditor shall make the disclosures required by this subpart in writing, in a form that the consumer may keep, except that:
(2) Terminology.
(3) Specific formats.
(iii) Telephone purchases. Disclosures required by § 1026.6 may be provided as soon as reasonably practicable after the first transaction if:
(ii) Timing requirements—(A) Credit card accounts under an open-end (not home-secured) consumer credit plan. For credit card accounts under an open-end (not home-secured) consumer credit plan, a card issuer must adopt reasonable procedures designed to ensure that:
(1) Periodic statements are mailed or delivered at least 21 days prior to the payment due date disclosed on the statement pursuant to § 1026.7(b)(11)(i)(A); and
(2) The card issuer does not treat as late for any purpose a required minimum periodic payment received by the card issuer within 21 days after mailing or delivery of the periodic statement disclosing the due date for that payment.
(B) Open-end consumer credit plans. For accounts under an open-end consumer credit plan, a creditor must adopt reasonable procedures designed to ensure that:
(1) If a grace period applies to the account:
(i) Periodic statements are mailed or delivered at least 21 days prior to the date on which the grace period expires; and
(ii) The creditor does not impose finance charges as a result of the loss of the grace period if a payment that satisfies the terms of the grace period is received by the creditor within 21 days after mailing or delivery of the periodic statement.
(2) Regardless of whether a grace period applies to the account:
(i) Periodic statements are mailed or delivered at least 14 days prior to the date on which the required minimum periodic payment must be received in order to avoid being treated as late for any purpose; and
(ii) The creditor does not treat as late for any purpose a required minimum periodic payment received by the creditor within 14 days after mailing or delivery of the periodic statement.
(3) For purposes of paragraph (b)(2)(ii)(B) of this section, “grace period” means a period within which any credit extended may be repaid without incurring a finance charge due to a periodic interest rate.