Mt. Gox was an online Bitcoin exchange, based in Tokyo. Prior to it being shut down in 2014, Mt. Gox was the largest Bitcoin exchange in the world, handling up to 70% of all Bitcoin transactions. In 2014, however, the exchange was suddenly closed and its owners filed for bankruptcy after 850,000 bitcoins ($460 mln at the time) have been stolen from the exchange by hackers. The attack was later revealed to have been made possible by the company's owners' poor management, neglect, and inexperience. The incident still serves as a reminder for many startups in the Bitcoin industry about the necessity of adequate security measures.