Several top lenders that issue non-agency MBS are also turning to in-house capital market operations to sell their deals to investors, a capability that other securitizers would like to have but hesitate to acquire. The capital market units of Countrywide Financial and Washington Mutual led a narrow field of in-house operations that underwrote most of their affiliates’ non-agency MBS originations during the first quarter of 2006, according to the Inside Mortgage Finance MBS Database.… [One data table included]