Struggling US brokerage firm MF Global has filed for bankruptcy after confidence in the company was shattered by a string of losses from European public debt holdings.
The firm filed for Chapter 11 bankruptcy protection in a Manhattan bankruptcy court on Monday, making it the first major US casualty from the European debt crisis.
While MF Global is well-known on Wall Street, it is not thought to be so interconnected that its collapse could trigger a crash like that seen in the wake of the Lehman Brothers bankruptcy in 2008.
But attention immediately turned to JPMorgan Chase and subsidiaries of Deutsche Bank, after MF's bankruptcy filing showed those firms to be its two biggest creditors.
JPMorgan was said to have a claim of over $1.2 billion with MF linked to bond holdings, while Deutsche Bank had a claim of over $1.0 billion.
Shares in JPMorgan fell 5.3 percent on the news while Deutsche Bank's US-listed shares fell 11.5 percent.
There were also signs that Washington was concerned.
The Financial Stability Oversight Council -- created during the 2008 crisis and comprising the heads of the Treasury, Federal Reserve, Securities and Exchange Commission, and Commodity Futures Trading Commission -- discussed the bankruptcy Monday.
"The... council convened today by conference call to review developments regarding MF Global and received a series of oral reports from the SEC, CFTC, and the Federal Reserve," a Treasury official said.
The New York Times, citing unnamed sources, reported late Monday that federal regulators were investigating hundreds of millions of dollars of customer money that had gone missing from MF Global's books in recent days.
The Times said the discovery of the missing funds had scuttled a last-ditch attempt by MF Global to save itself by selling a large part of its business to Interactive Brokers Group, a rival brokerage firm.
The newspaper cautioned that the missing funds could be the result of sloppy bookkeeping or represent something "more intentional and troubling."
Neither firm could immediately be reached for comment.
Shares in MF -- which had reported $41 billion in assets at the end of September -- were halted on the New York Stock Exchange early Monday in anticipation of the bankruptcy.
Ahead of the bankruptcy filing, Chris Low of FTN Financial wrote that MF's downfall would be "the biggest US casualty so far in the European sovereign crisis."
"Hopefully, the firm's situation is unique. (Chief executive Jon) Corzine's bet on sovereign debt is what got the firm in trouble. According to regulators, other, bigger US entities are not exposed."
According to figures from bankruptcydata.com, MF's filing is the eighth largest US bankruptcy in the past 30 years.
Lehman, the largest, had $691 billion in assets at the time of its collapse.
According to the bankruptcy filing, MF Global has 25,000-50,000 creditors and more than $1.0 billion in assets.