Fannie Mae and Freddie Mac in May resumed a more than year-long streak of declines with monthly decreases in the volume of single-family mortgages securitized by the two GSEs, according to a new Inside The GSEs analysis. Fannie and Freddie issued $44.8 billion in single-family mortgage-backed securities in May, a 1.3 percent decrease from the previous month. April’s $45.4 billion issuance proved to be just a brief reversal to the longer trend.