Baker & McKenzie is advising Tokyo-based bitcoin exchange Mt. Gox Co. Ltd. on a bankruptcy filing.

The petition follows the company’s announcement on Friday that hackers had apparently stole 750,000 bitcoins, an Internet-based currency not backed by any bank or government, that had been deposited by users and an additional 100,000 owned by the company itself. The total value of the stolen bitcoins was estimated at $480 million, accounting for 7 percent of all bitcoins traded globally.