One Year Ago

One year ago today the credit markets were seizing and the stock market was crashing. What have we learned about the causes of the meltdown? Was the primary cause the failure of the Fed to sufficiently regulate the subprime mortgage market or the securitization of loans? The bursting of a bubble? A failure by Congress to regulate Fannie and Freddie? A move toward deregulation nationally? Stupidity by institutional investors seeking returns on capital that could not be sustained? The wrong incentives for bankers or others (like compensation tied to short term gains)? Something else?