Filed by plaintiff Gregory Greene, the class action complaint filed in the US District Court of Chicago, alleges Green has lost $25,000 worth of the virtual currency. Green claims Mt. Gox and its chief executive, Mark Karpeles, were negligent and committed fraud for having failed to protect the Tokyo-based exchange from theft.
"Mt. Gox intentionally and knowingly failed to provide its users with the level of security protection for which they paid," said Greene.
Greene said bitcoin prices plummeted after Mt. Gox found the security breach, but said he and other investors in the virtual currency could not cut their losses because the exchange had halted trading. Mt. Gox took down its website on Tuesday.
Mt. Gox said it may have 750,000 of its customers' bitcoins and 100,000 of its own, equal to about 7 percent of bitcoins worldwide, for a total loss of about $480 million.
The case is Greene v. MtGox Inc, U.S. District Court, Northern District of Illinois, No. 14-01437.
Mr. Greene is represented by Steven Woodrow of Edelson PC.
