Armin Niedermeier, a spokesman for Frankfurt-based Deutsche Bank, declined to comment.

MF Global's 6.25 percent notes due 2016, which traded at 43 cents on the dollar earlier today, fell to 35 cents after the bankruptcy filing, according to Trace, the bond-price reporting system of the Financial Industry Regulatory Authority. The bonds traded as high as 104 cents as of Sept.7.

MF Global's largest shareholders include Pyramis Global Advisors LLC, with FMR LLC as custodian, with 8.4 percent of the stock, and RS Investments in San Francisco, with Guardian Life Insurance Co. as custodian, with 7.8 percent, according to court papers. As of June 30, MF Global had two series of preferred stock, including 1.5 million shares issued to J.C. Flowers & Co.

MF Global, formerly part of Man Group Plc, has its roots in a sugar brokerage founded by James Man in England in 1793. MF Global became a public company in a 2007 spinoff. The unit was built up before the spinoff by acquiring the assets of bankrupt brokerage Refco Inc. in 2005.

Broker-dealers aren't eligible to file for Chapter 11 bankruptcy, and need to either sell assets, as Bear Stearns Cos. did in 2008 to JPMorgan, or liquidate, as did Lehman Brothers Holdings Inc.'s brokerage unit and Bernard Madoff's firm. Liquidations are overseen by the Securities Investor Protection Corp. so as to return or replace customer securities. SIPC, created under the Securities Investor Protection Act, insures losses of as much as $500,000 a customer in registered securities.

Corzine, who helped run Goldman Sachs from 1994 to 1999, had sought to transform MF Global into a midsize investment bank since arriving there in March 2010. He increased the firm's risk and used its own money to trade, including investments in European sovereign debt that rattled markets.

Buyers Sought

Corzine, 64, reached out to Goldman Sachs about selling all or part of the company, according to two people with knowledge of the firm's deliberations. Macquarie Group Ltd. examined MF Global's books, according to a person with knowledge of the situation. Paula Chirhart, a spokeswoman for Macquarie in New York, declined to comment.

Barclays Plc was among banks that looked at MF Global, another person said. Kerrie Cohen, a bank spokeswoman in New York, declined to comment.

State Street Corp., which is also reported to be a potential bidder, doesn't comment on rumors, Hannah Grove, a spokeswoman for the Boston-based firm, said in an e-mail.