The Department of Justice is reportedly investigating Standard & Poor’s and Moody’s Investors Service regarding the ratings the firms placed on non-agency mortgage-backed securities. The increased attention on the rating services follows S&P’s recent downgrade of the credit rating for the U.S., revelations by a former Moody’s employee and numerous other investigations that found problems with the ratings on non-agency MBS. In a letter sent this month to the Securities and Exchange Commission, William Harrington, a former senior vice president at Moody’s, alleged that the rating service knowingly published “worthless opinions” on non-agency MBS. ...