Business is booming at Fannie Mae and Freddie Mac thanks to a healthy surge in refinance activity, according to a new Inside Mortgage Finance analysis of mortgage-backed securities issued by the two government-sponsored enterprises during the first quarter of 2015. Fannie and Freddie issued a total of $189.92 billion of single-family MBS during the first three months of the year. That was up 5.9 percent from the fourth quarter of 2014, and it marked the biggest output for the GSEs since the third quarter of 2013. Early 2015 was leaps and bounds ahead of the pace set during the same period last year, which marked a 14-year low in mortgage production. All of the oomph came...[Includes three data charts]