Mt. Gox Explained: The Collapse That Lost 850,000 Bitcoin
Mt.Gox was founded in 2010 by American Jed McCaleb; its name is short for Magic: The Gathering Online Exchange, and it began as a card-trading site be…
On February 28, 2014, in Tokyo, Mt.Gox — then the world's largest Bitcoin exchange — filed for bankruptcy. Three weeks earlier it had handled over 70% of global Bitcoin trading. Its bankruptcy paperwork admitted that roughly 850,000 bitcoin were missing, about 750,000 of them belonging to customers. No exchange failure has shaped Bitcoin more deeply. In Chinese-speaking communities, Mt.Gox is still nicknamed "Mentougou," after a Beijing district whose name sounds a little like "Mt. Gox."
What Mt.Gox was: from card-trading site to Bitcoin giant
Mt.Gox was founded in 2010 by an American, Jed McCaleb. Its name is short for "Magic: The Gathering Online Exchange" — it began as a card-trading marketplace before becoming a Bitcoin exchange. In 2011, McCaleb sold the company to a Frenchman living in Japan, Mark Karpelès.
At its peak the platform matched over 70% of global Bitcoin trading volume. It was not merely the biggest exchange; in practice it was the market. Back then, the dollar price of Bitcoin was, to a large degree, whatever Mt.Gox's order book said it was.
How it collapsed, step by step
The fall was not sudden. Later investigations found hackers had drained Mt.Gox's hot wallets since at least 2011 through leaked private keys — the keys to the money were outside the company's control, and for years nobody noticed.
On February 7, 2014, Mt.Gox suspended Bitcoin withdrawals, and customer balances became numbers users could see but not move. Panic, a run on the exchange, delistings, and rumors followed. Three weeks later, on February 28, Mt.Gox filed for bankruptcy in Tokyo. Bitcoin's price crashed that year and entered a long bear market; users were dragged into bankruptcy and rehabilitation proceedings that lasted years.
Where the 850,000 bitcoin went
The figures were staggering: about 850,000 bitcoin had vanished — roughly 750,000 belonging to users and about 100,000 belonging to the company, an astonishing slice of all circulating coins.
There was one twist: liquidators later found about 200,000 bitcoin in an old wallet. The rest was never fully recovered and is widely believed to have been moved, tumbled, and cashed out over the years. "I deposited coins and never saw them again" became a generational memory.
Karpelès's verdict, and the decade-long payout
In 2015, Mark Karpelès was arrested in Japan. In 2019, a Tokyo court found him guilty of data manipulation — falsifying records — and handed him a suspended sentence; charges including embezzlement were not upheld. In plain terms, he cooked the books but was not held criminally liable for stealing the money.
For creditors, the wait was far longer. The case moved from bankruptcy liquidation into civil rehabilitation, and under the rehabilitation plan repayments in Bitcoin and yen began in 2024 — a full decade after the coins vanished. Some were repaid when Bitcoin was worth far more than in 2014; others spent years proving a balance held a decade earlier.
Lessons for ordinary users
The sentence Mt.Gox burned into the industry is "Not your keys, not your coins." Coins left on an exchange are, in substance, a claim against it. If the platform is hacked, frozen, or bankrupted, the number on your screen may never turn into assets in your own wallet.
Three plain rules follow. Don't park large positions on an exchange for the long term. Move long-term holdings into a wallet whose seed phrase you control, and back that phrase up carefully (this guide to seed phrases and private-key safety covers the basics). And spread funds across several exchanges so one failure cannot wipe you out.
When choosing a venue, compare proof-of-reserves, security records, and withdrawal rules at major exchanges — Binance, OKX, and Gate.io — or use their official sign-up pages: Binance, OKX, and Gate.io. A top-tier exchange is not zero risk, but transparency and track record are useful filters.
FAQ
What does "Mentougou" mean?
The Chinese community's nickname for Mt.Gox, after a Beijing district whose name sounds similar; "the Mentougou incident" is the Chinese name for the collapse.
How much bitcoin did Mt.Gox lose?
Roughly 850,000 bitcoin were reported missing — about 750,000 belonging to users and about 100,000 to the company. Around 200,000 were later found in an old wallet; the rest was never fully recovered.
Did customers ever get repaid?
Partially, and only after a decade. Under civil rehabilitation, creditors began receiving repayment in Bitcoin and yen in 2024; amounts and timing varied by creditor and registration.
Did Mark Karpelès go to prison?
He was arrested in Japan in 2015. In 2019 a Tokyo court found him guilty of data manipulation — falsifying records — and gave him a suspended sentence; embezzlement charges were not upheld, so he served no prison time.
Risk warning
An exchange hack or bankruptcy can leave assets unreachable for years, and historical compensation is slow and uncertain. This article is a historical explainer, not investment advice.
Risk disclosure and affiliate notice: Trading and holding cryptocurrencies carry the risk of losing your principal, and keeping assets on an exchange means taking on the platform's credit and security risk. Nothing here is investment advice. This article contains affiliate links; signing up through them may earn us a commission at no extra cost to you, and it does not affect our independent judgment. The facts here are compiled from public sources and are current as of October 2026.