12 CFR § 12.9 - Settlement of securities transactions.
(a) All contracts effected or entered into by a national bank for the purchase or sale of a security (other than an exempted security as defined in 15 U.S.C. 78c(a)(12), government security, municipal security, commercial paper, bankers' acceptances, or commercial bills) shall provide for completion of the transaction within the number of business days in the standard settlement cycle followed by registered broker dealers in the United States, unless otherwise agreed to by the parties at the time of the transaction. The number of business days in the standard settlement cycle shall be determined by reference to paragraph (a) of SEC Rule 15c6–1, 17 CFR 240.15c6–1(a).
(b) Paragraphs (a) and (c) of this section do not apply to contracts:
(1) For the purchase or sale of limited partnership interests that are not listed on an exchange or for which quotations are not disseminated through an automated quotation system of a registered securities association;
(2) For the purchase or sale of securities that the SEC may from time to time, taking into account then existing market practices, exempt by order from the requirements of paragraph (a) of SEC Rule 15c6–1, 17 CFR 240.15c6–1(a), either unconditionally or on specified terms and conditions, if the SEC determines that an exemption is consistent with the public interest and the protection of investors.
(c) Paragraph (a) of this section does not apply to contracts for the sale for cash of securities that are priced after 4:30 p.m. Eastern time on the date the securities are priced and that are sold by an issuer to an underwriter pursuant to a firm commitment underwritten offering registered under the Securities Act of 1933, 15 U.S.C. 77a et seq., or sold to an initial purchaser by a national bank participating in the offering. A national bank shall not effect or enter into a contract for the purchase or sale of the securities that provides for payment of funds and delivery of securities later than the fourth business day after the date of the contract unless otherwise expressly agreed to by the parties at the time of the transaction.
(d) For purposes of paragraphs (a) and (c) of this section, the parties to a contract are deemed to have expressly agreed to an alternate date for payment of funds and delivery of securities at the time of the transaction for a contract for the sale for cash of securities pursuant to a firm commitment offering if the managing underwriter and the issuer have agreed to the date for all securities sold pursuant to the offering and the parties to the contract have not expressly agreed to another date for payment of funds and delivery of securities at the time of the transaction.