Mt. Gox has discovered 200,000 missing bitcoins in a wallet no longer in use, the troubled Bitcoin exchange announced Thursday, reducing the number of missing bitcoins from 850,000 to 650,000. “We believed there were no bitcoins left in old wallets, but found 199,999.99 bitcoins on March 7,” Mt. Gox Chief Executive Officer Mark Karpeles said in a document (PDF) released Thursday. Mt. Gox said it reported the discovery to attorneys on March 8 and moved the newfound bitcoins to offline storage. Once one of the largest and most popular Bitcoin exchanges, Mt. Gox filed for bankruptcy last month, saying it had lost nearly 750,000 customer bitcoins, as well as 100,000 of the exchange’s own bitcoins, as a result of a security lapse. The discovery of the overlooked bitcoins apparently occurred before hackers hijacked and defaced Karpeles’ Reddit account and personal blog with charges of fraud earlier this month.