SIFMA provides comments to the Securities and Exchange Commission (SEC) on Temporary Rule 206(3)-3T under the Investment Advisers Act of 1940 (Advisers Act) relating to principal trades with certain advisory clients, Release No. 1A.-2653; File No. S7-23-07.  SIFMA believes the SEC should consider expanding the list of underwritten securities eligible for principal transactions under the proposed rule, and shares its observations and recommendations on other issues relating to the proposal including client and account eligibility, and application of the proposed rule.