Fannie Mae and Freddie Mac issued a robust $189.92 billion of single-family mortgage-backed securities during the first three months of 2015, according to a new Inside The GSEs analysis.Business in the GSEs’ core MBS guaranty program grew 5.9 percent from the fourth quarter of last year. The pace in early 2015 was up a hefty 47.0 percent from the same period last year, which was the weakest quarter in over a decade. Nonbank seller/servicers continued to gain market share. These companies accounted for 45.6 percent of GSE MBS issued in early 2015, and their total production was up 7.7 percent from the previous quarter. (Includes 2 exclusive charts).