It isn't clear how much money Corzine is worth. He spent roughly $100 million of his fortune to win a U.S. Senate seat and the New Jersey governorship. In 2005, the last full year that he was a U.S. senator, he was estimated to be worth between $125 million and $175 million.
MF Global sought bankruptcy protection in 2011 after a disastrous bet on European countries' debt. Under Corzine's leadership, the firm bet $6.3 billion on bonds issued by Italy, Spain and other nations with deeply troubled financial systems. Those bonds plummeted in value in the weeks before MF Global's failure as fears intensified that some European countries might default.
The firm's $41 billion bankruptcy was the eighth-largest in U.S. history. It was also the first collapse of a Wall Street firm since the 2008 financial crisis ended. Critics have long complained that regulators have failed to aggressively pursue much bigger financial firms, whose high-risk bets nearly toppled the financial system.
Corzine, 66, had been a CEO of Wall Street powerhouse Goldman Sachs before entering politics in 2000. He served as a Democratic U.S. senator from New Jersey and later governor of the state. He took the top job at MF Global in March 2010 after losing his 2009 bid for re-election as governor to Chris Christie.
MF Global was a small commodities broker when Corzine arrived. His vision was to transform the firm into a full-scale investment bank, similar to Goldman. The CFTC's lawsuit says he sought to do so by generating revenue from aggressive trading strategies.
The plan worked for a while even as the firm's investments grew increasingly risky, the lawsuit said. In the second half of 2011, its investments put heavy strains on its cash flow and capital. By October 2011, the lawsuit says, sources of cash were drying up.
Corzine and other employees communicated with one another, by email and sometimes on recorded phone lines, about the firm's "dire situation," the lawsuit says.
It says a treasurer of the firm's parent company, MF Global Holdings Ltd., told a chief financial officer and another employee in a recorded conversation on Oct. 6, 2011, that "we have to tell Jon that enough is enough. We need to take the keys away from him."
Corzine "disparagingly nicknamed the Global treasurer 'the Gravedigger,'" the lawsuit says
Corzine stepped down as MF Global chief in November 2011, a few days after the firm filed for bankruptcy protection.
Three reports on MF Global's collapse, by a House panel and two court-appointed trustees, placed most of the blame on Corzine. It said his risky strategies caused the failure.
Shareholders of MF Global have sued Corzine and other top managers. The investors say they lost about $585 million in just a week as the firm foundered. They accuse MF Global and the executives of making false and misleading statements about the firm's financial strength.
Giddens, the trustee, also joined a lawsuit filed by MF Global customers against Corzine and the other top executives.
Corzine testified at three hearings of House and Senate committees in December 2011 after lawmakers subpoenaed him. It was a rare sight in Washington: A former member of Congress being called by former colleagues to testify publicly about potential violations of law.
Corzine's testimony offered little to satisfy lawmakers or MF Global customers who lost money. Yet his explanations would be hard to disprove, legal experts said.
He said he never intended to "misuse" client money or to order anyone else to do so. Corzine also rebuffed an assertion that he knew about customer money that might have been transferred to a European affiliate just before MF Global collapsed.
O'Brien, the former assistant treasurer, was subpoenaed to testify at a hearing last year about an email she sent that appeared to contradict testimony from Corzine. The email said Corzine ordered a transfer of customer money to cover an overdraft in the firm's bank account in London.
"On the advice of counsel," she told Congress, "I respectfully decline to answer based on my constitutional right."
Neumeister and Rexrode contributed from New York.