The Federal Housing Finance Agency this week detailed its efforts to make sure Fannie Mae and Freddie Mac policies and practices are consistent enough to keep prepayments speeds on their to-be-announced securities essentially the same. Prepay speeds for the two government-sponsored enterprises have moved significantly closer as more of their products and program requirements have been standardized, the FHFA said in an update on its single security initiative. Keeping them that way is seen as critical to the success of the program, in which Fannie and Freddie TBA MBS will be fully fungible – and can even be combined in so-called second-tier securitizations. Some industry interests have urged...