The GSEs’ share of total new mortgage originations continued to fall during the first half of 2005, as both Fannie Mae and Freddie Mac faced regulatory challenges during shifting market conditions. According to data tracked by Inside The GSEs, Fannie, Freddie and the Federal Home Loan Banks accounted for just $533 billion of the estimated $1.42 trillion in overall originations during the first half of 2005. That represented just 37.5 percent of the mortgage market…