Mt. Gox
On 13 June 2011, the Mt. Gox bitcoin exchange reported some 25,000 BTC (US$400,000 at the time) robbed from 478 accounts. Then on Friday 17 June, Mt. Gox's user database leaked for sale to pastebin, signed by "~cRazIeStinGeR~" and tied to "auto36299386@hushmail.com". The theft of Bitcoins from Mt. Gox accounts continued, reportedly, throughout that day. On 19 June, a stream of fraudulent trades caused the nominal price of a bitcoin to fraudulently drop to one cent on the Mt. Gox exchange, after a hacker allegedly used credentials from a Mt. Gox auditor's compromised computer to transfer a large number of bitcoins illegally to himself. He used the exchange's software to sell them all nominally, creating a massive "ask" order at any price. Within minutes the price corrected to its correct user-traded value. Accounts with the equivalent of more than $8,750,000 were affected. To prove that Mt. Gox still had control of the coins, the move of 424,242 bitcoins from "cold storage" to a Mt. Gox address was announced beforehand, and executed in Block 132749.