The Tower Amendment is a 1975 amendment to the United States Securities Exchange Act of 1934.
In the same year, the Municipal Securities Rulemaking Board (MSRB) had been put in place and was a driving force behind the Tower Amendment. Authored by the former Republican Senator John Tower of Texas, the amendment prohibits the SEC and MSRB from directly or indirectly requiring issuers to file municipal securities documents with them before the securities are sold.
References
Tower Amendment Wikipedia(Text) CC BY-SA