SIFMA provides comments to the Securities and Exchange Commission (SEC) on the Financial Industry Regulatory Authority’s (FINRA’s) proposed rule change that would begin dissemination of data for Agency mortgage-backed securities traded on a To-Be-Announced (TBA) basis, Release No. 34–65877, File No. SR–FINRA–2011–069.  SIFMA shares recommendations that are narrowly tailored and focused on two aspects of the proposal. The first area is the cap on disseminated volume, and the second regards certain implementation considerations for the rule proposal.  SIFMA concerns also stem from a mistaken characterization of TBA trading corresponding to a unitary TBA market. In reality, there are a number of MBS markets where securities are traded TBA, each with different liquidity and operational realities that should be reflected in the TRACE reporting regime.