Fannie Mae and Freddie Mac will not be branching out into the role of a “master servicer” in a new, yet-to-be-launched $2 billion bond program as top Republican members of the House Financial Services Committee feared, according to Treasury Secretary Timothy Geithner.In a letter dated July 21 and in response to a letter sent by Committee Chairman Spencer Bachus, R-AL, Vice Chairman Jeb Hensarling, R-TX, and four of the committee’s subcommittee chairman, Geithner firmly ruled out any participation by the two GSEs in Treasury’s loan-guarantee program.