Two class-action lawsuits have been filed against bankrupt brokerage MF Global as customers struggle to recover funds from the first major US casualty of the European debt crisis.

On Saturday, Seattle-based Hagens Berman said it was "investigating whether the company used clients' money to offset losses the company had incurred in failed investments."

It filed a lawsuit in the name of investors who bought MF Global shares between May 20 and October 28 or who bought bonds issued in August.

The complaint charged that MF Global "made false and misleading statements to investors, including failing to disclose the company's reported internal control problems in segregating clients' funds."

Attorney Reed Kathrein said Friday's resignation of the company's chief executive Jon Corzine, whose activities in the last weeks of the failing firm have attracted regulator scrutiny, was "not an encouraging sign."

"As we continue our investigation, we hope to uncover whether the company mixed investors' and company money, and if Corzine himself played a part in that decision," he added in a statement.

Boston law firm Block & Leviton said Friday it had also filed a class-action lawsuit in New York federal court on behalf of MF Global clients over the same period.

It charged MF Global made "certain materially false and misleading statements regarding the Company's internal financial controls and liquidity levels" through its "most senior" officers and directors.

Investors lost some $585 million in market capitalization in the week that preceded MF Global's bankruptcy filings alone, according to Block & Leviton.

MF Global filed for bankruptcy last Monday after confidence in the company was shattered by a string of losses from European public debt holdings.

According to the bankruptcy filing and its third-quarter financial report, MF Global has 25,000-50,000 creditors and around $40 billion in debts.

The company reported mounting losses related in part to a portfolio of $6.3 billion in high-risk European bonds, which it had reportedly used as collateral to raise even more funding, much of its short-term.

That funding apparently dried up as the company's troubles became more evident, and a rush to find an investor or buyer failed.