May 10, 2011 - Bitcoin7 11,000 BTC

Bitcoin7 Incident
Time: 2011-10-05 (UTC)
Victim: Bitcoin7 & Customers
Status: Indeterminate amount returned to customers by Bitcoin7
Suspects:

• Official story: Potential “inside job” (an employee perpetrated a theft). Official statement by Bitcoin7 owners in a listing to sell the code behind Bitcoin7.
• Previous official story: Unknown hacker from Eastern Europe or Russia.Initial official statement by Bitcoin7, quoted by Stephen Gornick and retrieved on BitcoinTalk.
• Suspected scam by several members of the community.

Amount: Lower bound 5000 BTC, 5000 BTC is almost certainly a low estimate, as the source is a listing that promotes the successes of Bitcoin7 and fails to acknowledge the severity of the theft. If Bitcoin7 disappeared, then the value should be bounded above by 15000 BTC, which is based on the size of order books at the time.
Equivalent in USD: 15980 $
Equivalent in January 2014 BTC: 20.7 BTC
An upstart exchange at the time, Bitcoin7, rapidly grew to the third-largest USD exchange (behind then-leaders Mt. Gox and Tradehill) but then suffered a major debilitating hack, or so the official story goes. It is widely suspected that there was no hack and Bitcoin7’s operators simply ran away with the funds.

Bitcoin7 shut down because of this hack. The magnitude served as a reminder to the Bitcoin community to stop trusting new exchanges without identification. The platform was however later sold for $10000 in 2013, and has since relaunched at Bitcoiner7.com but being branded still as Bitcoin7.