The U.S. government expects to come up with a plan by year-end to gather more complete data on trading in the Treasuries market. It may also decide how much of the information—if any—it will release to taxpayers.

The Treasury Department is developing a plan for regulators to access "all cash Treasuries data," U.S. Treasury Counselor Antonio Weiss told subcommittees of the Senate Banking Committee Thursday. By year-end, the Treasury also "will have articulated a point of view about post-trade reporting" of data, he said.

The question of how widely trading data should be disseminated is a "controversial" one, Weiss said. It's the opening debate in the government's first review since 1998 of the structure of the $13.4 trillion market. The workings of the benchmark market for global borrowing—among the world's deepest and most liquid—had largely gone without scrutiny until a 12-minute crash and rebound in yields on Oct. 15, 2014.