Redwood Trust, which pioneered the revival of the jumbo MBS market a few years back, this month officially exited the Fannie Mae/Freddie Mac correspondent-purchase business, dismantling the effort and trimming the size of its Denver office. The real estate investment trust had entered the government-sponsored enterprise market two years ago, after obtaining agency approvals at the end of 2013. It quickly built a network of several dozen lenders that sold whole loans to Redwood, which pooled them in GSE MBS. But sources familiar with the effort told...