Real estate investment trusts that specialize in the residential MBS market held $232.44 billion of agency and non-agency MBS at the end of March, according to a new Inside MBS & ABS analysis. The MBS holdings of 16 top mortgage REITs were down 0.3 percent from the fourth quarter and off 11.9 percent from March 2015. However, several REITs boosted their positions during early 2016 and the industry is slated to see a major merger of two firms ... [Includes one data chart]