Moody’s Rebounds in Non-Agency MBS Ratings Derby , Edges Into Lead in Non-Mortgage Deals Moody’s Investors Service has significantly increased its market share in the ratings of non-agency MBS during early 2004, a business that continues to be dominated by Standard & Poor’s. According to a new analysis of rating agency market shares, Moody’s stamped its credit grade on 81.6 percent of the non-agency MBS issued in the first quarter of 2004, based on dollar