Call it the year of the stealth bankruptcy.

After two years of colossal corporate meltdowns--the liquidations of Lehman Brothers and Circuit City, the General Motors and Chrysler bankruptcies, the near failures of AIG and Citigroup--2010 seemed like a year of convalescence. The default rate on corporate debt, according to Moody's, plummeted from the peak levels of 2009 and headed back toward pre-recession levels. The biggest bankruptcy of the year was a company most Americans have never heard of--bond insurer Ambac--and investors saw it coming so far in advance that the markets barely reacted. And overall corporate profits reached stratospheric levels, signaling boom times for companies that endured the Great Recession and lived to tell the tale.