First Republic Bank is one of the few bank originators of non-agency jumbo mortgages that has sold a significant share of its production in the secondary market in the past year. Officials at the bank said the sales have been driven by borrowers’ preference for 30-year fixed-rate mortgages and investor demand in the non-agency market, both of which have changed recently. In the first quarter of 2013, First Republic originated $2.32 billion of mortgages, including $1.85 billion in non-agency jumbo mortgages ...