Eugene Fama on ratings agencies and problems in mortgage markets:
Interview with Eugene Fama, by Douglas Clement, The Region. FRB Minneapolis: ... Region: Some observers have suggested that regulators and others have put too much reliance on ratings agencies to determine the risk of mortgage-backed securities and that even financially sophisticated parties “didn’t really know what they were buying.” Is this evidence that credit markets are inefficient?
Fama: That story just doesn’t appeal to me. First of all, it’s well known that rating agencies tend to lag actual changes in credit worthiness. For example, stock prices predict changes in ratings better. The best models of credit quality are basically options pricing models that work off the stock price. So I’m very skeptical of these stories.
The bond market is a simpler market than the stock market. Bonds are simpler to evaluate than stocks, because there’s downside risk, but you don’t have to worry much about the upside: They’re not going to pay you more than they promised. So bonds are much simpler to deal with. Now bond products have become more complicated because of the securitization of that market, but still not that big a deal. [entire interview]