17 CFR § 230.173 - Notice of registration.
(a) In a transaction that represents a sale by the issuer or an underwriter, or a sale where there is not an exclusion or exemption from the requirement to deliver a final prospectus meeting the requirements of section 10(a) of the Act pursuant to section 4(3) of the Act or Rule 174 (§ 230.174), each underwriter or dealer selling in such transaction shall provide to each purchaser from it, not later than two business days following the completion of such sale, a copy of the final prospectus or, in lieu of such prospectus, a notice to the effect that the sale was made pursuant to a registration statement or in a transaction in which a final prospectus would have been required to have been delivered in the absence of Rule 172 (§ 230.172).
(b) If the sale was by the issuer and was not effected by or through an underwriter or dealer, the responsibility to send a prospectus, or in lieu of such prospectus, such notice as set forth in paragraph (a) of this section, shall be the issuer's.
(c) Compliance with the requirements of this section is not a condition to reliance on Rule 172.
(d) A purchaser may request from the person responsible for sending a notice a copy of the final prospectus if one has not been sent.
(e) After the effective date of the registration statement with respect to an offering, notices as set forth in paragraph (a) of this section, are exempt from the provisions of section 5(b)(1) of the Act.
(f) Exclusions. This section shall not apply to any:
(1) Transaction solely between brokers or dealers in reliance on Rule 153 (§ 230.153);
(4) Offering registered on Form S-8 (§ 239.16b of this chapter).