Enron:
The energy company's bankruptcy in 2001 after allegations of massive accounting fraud wiped out $78 billion in stock market value and led to the collapse of Arthur Andersen and the passage of the Sarbanes-Oxley Act of 2002. A class action settlement of $7.185 billion was the largest of all time. Former President Jeff Skilling is serving a 24 year sentence.
Bernard Madoff:
New York money manager Bernard Madoff's $65 billion Ponzi scheme, the largest fraud ever by an individual, was exposed in December 2008 when Madoff, now doing 150 years in prison, confessed to his sons. The case led the SEC, which missed several opportunities to stop the fraud, to focus on Ponzis and investment advisor fraud.
Lehman Brothers:
Investment bank Lehman, with $600 billion in assets, failed in late 2008. It was the largest bankruptcy in history and a spark to the worldwide financial crisis. A bankruptcy examiner's report concluded there were "colorable" claims against its top executives and its auditor, Ernst & Young, for fraud, but neither the SEC nor the DOJ have so far filed charges.
Cendant:
Shortly after the company was created by the merger of CUC International and HFS in 1997, a massive, decade long accounting fraud at CUC was uncovered. It was estimated to have cost investors at least $19 billion, and was the largest fraud prosecuted by the SEC to that date. Securities class action lawsuits settled later for more than $3 billion. A judge sentenced former chairman Walter Forbes to 12 years and seven months in federal prison and ordered him to pay $3.275 billion in restitution.
MF Global:
The brokerage firm, led by former Goldman Sachs Chairman and former New Jersey Senator then Governor Jon Corzine, had $41 billion in assets before failing in October 2011. That put MF Global at #8 on the list of ten largest bankruptcies. A year later, $1.6 billion in customer assets were still missing and no SEC or DOJ