An Illinois man has filed a class-action lawsuit against MtGox, alleging consumer fraud, negligence, breach of fiduciary duty, and breach of contract, among other allegations. The case appears to be the first such class-action suit filed in the United States against the failed Bitcoin exchange.

MtGox filed for bankruptcy protection in Japan on Friday.

In a 32-page filing submitted Thursday to the Northern District of Illinois, Gregory Greene says that he first encountered MtGox in late 2011 and signed up for an account. Greene, like many others, attempted to withdraw his bitcoins from MtGox once the company announced that it had sustained a massive security breach. However, given the company’s sudden shutdown and subsequent application for bankruptcy protection, Greene was unable to do so.

The lawsuit defines members of the class as “[a]ll persons in the United States who had bitcoins or Fiat Currency stored with Mt. Gox on February 7, 2014," which the filing speculates could be hundreds of thousands of people.

MtGox CEO Mark Karpeles did not respond to Ars’ request for comment concerning the lawsuit.

Greene’s court filing states that had he known of the company’s “substandard security procedures that left his bitcoins vulnerable to theft, he would have paid substantially less for Mt. Gox’s services or would not have paid at all.”

The document continues:

Worse yet, at the time Mt. Gox shut down, Greene had used Mt. Gox’s services to store and protect bitcoins with a present value of approximately $25,000 dollars. Despite his repeated attempts, Greene has been unable to withdraw his money from Mt. Gox since early February 2014. Prior to February 7, 2014, Plaintiff’s bitcoins had a market value of nearly double their value following Mt. Gox’s prohibition on withdrawals and eventual shutdown, which undeniably caused a sharp decline in the market value of bitcoins.

While this represents possibly the first such suit against MtGox in the United States, there are other lawsuits currently pending that allege shady dealings by other Bitcoin-related companies, including one targeting Butterfly Labs, a Kansas-based manufacturer of Bitcoin miners.

UPDATE 2:50pm CT: Greene's lawyer, Jay Edelson, told Ars that MtGox has not responded at all, and added: