Issuance of agency MBS has dropped off in the past year due to a decline in the supply of refinances. However, industry analysts expect that Fannie Mae and Freddie Mac will boost the supply of agency MBS with issuance backed by modified mortgages and re-performing loans. Fannie and Freddie could have $250 billion in modified mortgages on their balance sheets, according to estimates by Deutsche Bank Securities. The two government-sponsored enterprises will likely unload the holdings via securitization, prompted by portfolio reduction goals established by the Federal Housing Finance Agency. Freddie has been...