California remains the top source of new single-family mortgages for Fannie and Freddie, 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 $132.2 billion of home loans on Golden State properties were securitized by the two GSEs during the first six months of 2012, accounting for 22.9 percent of their total business for the half year. That was up 46.7 percent from total California production during the first six months of 2011 as the overall GSE market rose 38.8 percent from a year ago.