They were selling ratings on bonds instead of doing what they're actually supposed to do, which is evaluate the bond on it's merits and then assign it a rating.

They were selling ratings on bonds instead of doing what they're actually supposed to do, which is evaluate the bond on it's merits and then assign it a rating. It was pay-for-ratings instead of pay-for-evaluation. This is documented pretty well in Michael Lewis' and Matt Taibbi's books about the 2008 financial crash.