Collapse of Mt. Gox

The collapse of Mt. Gox was the sequence of events that led to the February 2014 shutdown and insolvency of what had been the largest Bitcoin exchange. The Tokyo-based company stopped Bitcoin withdrawals on 7 February, suspended trading on 24 February and filed for civil rehabilitation in Japan on 28 February. It initially reported that approximately 850,000 BTC belonging to customers and the company could not be accounted for.

The failure was not one isolated event. It followed years of wallet losses, security incidents, unreliable accounting, banking and regulatory problems, and increasingly delayed customer withdrawals. Later transaction analysis and criminal allegations described theft beginning in 2011, well before the public shutdown.

Conditions before the shutdown

Mt. Gox held customers' national currency and Bitcoin in custodial accounts and matched trades inside its own database. Customers therefore depended on the exchange to maintain accurate balances, protect wallet keys and honor withdrawals. By the first half of 2013, Mt. Gox accounted for nearly three quarters of reported Bitcoin exchange trading, concentrating a large part of the young market's custodial risk in one company.

The exchange had already experienced a major account and database compromise in June 2011. An attacker used credentials from a compromised auditor account to place fraudulent trades, briefly driving the displayed price to one cent; a user-database disclosure also exposed email addresses and password hashes. Mt. Gox rolled back the affected trades, but the incident demonstrated weaknesses in its access controls and account security.

Financial pressure intensified in 2013. CoinLab sued Mt. Gox for US$75 million after a planned transfer of the exchange's North American business failed, while Mt. Gox alleged that CoinLab had retained US$5.3 million in customer deposits. U.S. authorities seized more than US$5 million from associated accounts after alleging that a subsidiary had operated without required money-services registration.

Mt. Gox paused U.S.-dollar withdrawals in June. Although it later announced a resumption, customers continued to report delays of weeks or months; by November, the Japanese bank processing international payments was reportedly limiting the exchange to ten outgoing wire transfers per day. These cash bottlenecks did not reveal the size of the Bitcoin shortfall, but they reduced the exchange's ability to meet withdrawals and obscured its financial condition.

February 2014 timeline

On 7 February, Mt. Gox halted Bitcoin withdrawals. Three days later it blamed transaction malleability, a real property of then-current Bitcoin transactions that could allow the transaction identifier to change without changing the payment. Mt. Gox argued that altered identifiers could make completed withdrawals look unsuccessful.

That explanation was disputed. Other exchanges resumed withdrawals after adjusting their systems, while Mt. Gox remained closed. A later academic analysis of public blockchain data found no evidence that widespread transaction-malleability attacks accounted for the missing amount before the collapse.

On 23 February, chief executive Mark Karpelès resigned from the Bitcoin Foundation's board. Mt. Gox suspended trading the next day and its website went blank. Six other Bitcoin businesses issued a joint statement distancing Bitcoin and their exchanges from Mt. Gox. A leaked crisis document claimed that hundreds of thousands of bitcoins had been lost over several years; the document was not an audited statement, but the scale was soon broadly confirmed by the company's court filing.

On 28 February, Mt. Gox sought civil rehabilitation in the Tokyo District Court. It reported an initial shortfall of about 850,000 BTC—approximately 750,000 BTC attributed to customers and 100,000 BTC attributed to the company—along with liabilities of approximately US$63.6 million and assets of approximately US$37.7 million. A Chapter 15 petition seeking U.S. recognition of the Japanese proceeding followed in March. In April, the Japanese court moved the company from the attempted rehabilitation into bankruptcy liquidation.

Missing bitcoins and investigation

In March 2014, Mt. Gox disclosed that it had located 200,000 BTC in an old-format wallet that the company had believed was empty. The discovery reduced the reported missing amount to approximately 650,000 BTC.

WizSec, an independent security group, later analyzed leaked exchange records and blockchain transactions. It concluded that most or all of the missing bitcoins had been removed from Mt. Gox hot wallets gradually, beginning in late 2011, and that the exchange had operated while already insolvent. The analysis also distinguished the wallet theft from suspicious internal trading bots that appeared later. This was an independent reconstruction rather than a court judgment.

In 2017, U.S. prosecutors alleged that BTC-e operator Alexander Vinnik received and laundered proceeds connected to the Mt. Gox theft. In 2023, the U.S. Department of Justice charged Alexey Bilyuchenko and Aleksandr Verner with conspiring to hack Mt. Gox and launder approximately 647,000 BTC. The accusations are allegations in criminal indictments, and the defendants are presumed innocent unless proved guilty.

Japanese prosecutors brought separate charges against Karpelès concerning Mt. Gox's internal records and funds. In 2019, the Tokyo District Court convicted him of falsifying electronic data and imposed a suspended sentence, while acquitting him of embezzlement. That judgment did not establish that he carried out the large wallet theft.

Creditor proceedings and repayments

The liquidation process preserved a pool of recovered Bitcoin, Bitcoin Cash and cash for creditors. Because Bitcoin's market value rose substantially after 2014, creditors sought civil rehabilitation, which could distribute the remaining cryptocurrency rather than value every Bitcoin claim only at the earlier bankruptcy price.

The Tokyo District Court commenced civil rehabilitation on 22 June 2018, staying the earlier bankruptcy proceeding. Creditors approved a rehabilitation plan in 2021, and the confirmation order became final and binding that November.

The trustee began Bitcoin and Bitcoin Cash repayments through designated exchanges in July 2024 and reported further distributions in 2024 and from January through March 2025. Repayments did not finish for every eligible creditor. As of 13 September 2026, the trustee's published deadline for base, early lump-sum and intermediate repayments was 31 October 2026. This date and the status of individual claims can change; the trustee's official notices are the controlling current source.

Significance

The collapse demonstrated the difference between Bitcoin's ledger security and the security of a custodial intermediary. The Bitcoin network continued operating, but customers who had transferred keys or national currency to Mt. Gox depended on the exchange's wallet controls, database and solvency. The event accelerated scrutiny of exchange custody, proof-of-reserves claims, accounting controls and regulation.

It also shows why loss figures require context. The 850,000 BTC figure was the initial reported shortfall; about 200,000 BTC was later recovered. Amounts held or distributed by the trustee are not equivalent to the total historically stolen, because the estate also contains cash, forked assets and proceeds from earlier sales.

External links

• Rehabilitation trustee announcements
• WizSec transaction analysis