Together, Fannie Mae and Freddie Mac in October posted a combined decline in the volume of single-family mortgages securitized, according to a new Inside The GSEs analysis. Fannie and Freddie issued $63.1 billion in single-family mortgage-backed securities in October, a 1.5 percent decrease from September. On a year-to-date basis, October’s MBS issuance dropped an even steeper 50.6 percent.