The Bitcoin exchange that collapsed after filing for bankruptcy in 2014 was Mt. Gox.
Mt. Gox began as a website for trading “Magic: The Gathering Online” cards before becoming a Bitcoin exchange. Its name came from “Magic: The Gathering Online eXchange.” Based in Tokyo, it grew into one of the largest Bitcoin exchanges by trading volume during the early 2010s.
In February 2014, Mt. Gox halted trading, suspended withdrawals, and filed for bankruptcy protection in Japan. The exchange reported that approximately 850,000 bitcoins belonging to customers and the company were missing, although some coins were later found. The collapse became one of the defining security and custody failures in Bitcoin’s early history.
Mt. Gox is an exchange name, not a Bitcoin protocol feature. The incident also illustrates why ownership on a trading platform differs from control of coins in a personal wallet: customers depended on the exchange to hold and transfer their funds. Legal proceedings and creditor rehabilitation continued long after the 2014 collapse.