California remains the top source of new single-family mortgages for Fannie Mae and Freddie Mac, even as Fannie remains the dominant GSE in terms of production through the first half of the year, according to an Inside The GSEs analysis. A total of $160.3 billon home loans on Golden State properties were securitized by the two GSEs during the first six months of 2013, accounting for 23.1 percent of their total business for the half year. That was up 21.2 percent from total California production during the first six months of 2012 as the overall GSE market rose 20.2 percent from a year ago.