Fannie Mae and Freddie Mac saw their combined business in single-family mortgage-backed securities decline during the first six months of 2013 with nonbank lenders making up well over one-quarter of their business, according to an Inside The GSEs analysis. The two GSEs pumped out some $693.6 billion in new single-family MBS during the first and second quarters. With a 28.5 percent market share, nonbank sellers accounted for $197.4 billion of Fannie and Freddie loans sold during the January through June period.Nonbanks as a whole made the most of the retail channel (55.1 percent) during the six-month period, which was generally comparable to all GSE sellers (60.2 percent), while the gap widened in the correspondent channel between nonbanks (19.9 percent) and all GSE sellers (29.0 percent).