Agency MBS backed entirely by “conforming jumbo” mortgages was one of the fastest-growing sectors of the market last year, but traditional 30-year fixed-rate mortgages remained the overwhelming favorite, according to a new analysis by Inside MBS & ABS. Fannie Mae and Freddie Mac issued $21.17 billion of jumbo-only MBS in 2015, a 90.2 percent increase from the previous year. Ginnie Mae issuance of such pools was up even more, by 163.0 percent, last year. Conforming-jumbo loans are...[Includes two data tables]