Mt. Gox, once handling 70% of all Bitcoin transactions, lost 850,000 BTC through years of theft and mismanagement.
Mt. Gox lost Bitcoin through multiple incidents spanning 2011-2014. Transaction malleability attacks allowed the exchange to be tricked into reissuing withdrawals. Poor security practices, unencrypted hot wallets, and lack of auditing allowed hackers to drain funds over years. The exchange filed for bankruptcy in February 2014.
BTC dispersed over years through early Bitcoin exchanges and OTC markets. Alexander Vinnik, linked to the theft, processed funds through BTC-e exchange (later seized by DOJ). Approximately 142,000 BTC recovered in cold wallets. Creditors received partial repayment in 2024 through bankruptcy proceedings.
N/A - multiple transactions over years