A few examples of rating agency miscues include the following events. In December 2001, Enron was rated investment grade on a Friday. On Sunday, it filed for bankruptcy. Also at that time, S&P rated Tyco bonds as investment grade (BBB), although the market clearly priced Tyco bonds in the junk category. And by the time the rating services downgraded WorldCom to junk status in May 2002, the market had reflected that fact for some time. The lesson that investors should take from this is that bond ratings are simply one piece of information. They don’t substitute for investors doing their own analysis (or “due diligence”).