For years, the ratings agencies have contended that the grades they assign debt securities are independent opinions and therefore entitled to First Amendment protections, like those afforded journalists. But newly released documents in a class-action case ... cast doubt on the independence of the two largest agencies, Moody's Investors Service and Standard & Poor's. The case, filed in 2008 by a group of 15 institutional investors against Morgan Stanley and the two agencies, involves a British-based debt issuer called Cheyne Finance. Cheyne collapsed in August 2007 under a load of troubled mortgage securities. Even though Cheyne's portfolio was bulging with residential mortgage securities, some of its debt received the agencies' highest ratings, a grade equal to that assigned to United States Treasury securities. When the primary analyst at S.& P. notified Morgan Stanley that some of the Cheyne securities would most likely receive a BBB rating, not the A grade that the firm had wanted, the agency received a blistering e-mail from a Morgan Stanley executive. S.& P. subsequently raised the grade to A. After the institutions that bought Cheyne's debt sued Morgan Stanley and the ratings agencies, Moody's and S.& P. immediately mounted a First Amendment defense. But Shira A. Scheindlin, the federal judge overseeing the matter ... argued that the ratings were not opinions but were misrepresentations that were possibly a result of fraud or negligence.