Go read William K. Black[0] on the subject of accounting control fraud. He's the author of The Best Way to Rob a Bank is to Own One: How Corporate Executives and Politicians Looted the S&L Industry [2005] He was one of the lead regulators during the Savings and Loan crisis. Follow a few of the links on his Wikipedia page. It was fraud: massive and with regulators (led by Alan Greenspan) turning a blind eye.