The Tokyo-based bitcoin exchange that was once the largest in the world abruptly closed on 25 February. Its website is offline and its headquarters are empty. The only activity is outside its offices, where protesters are picketing after losing money on their bitcoin investment. Wired.com reports that the closure is the result of Mt. Gox “losing hundreds of millions of dollars due to a years-long hacking effort that went unnoticed by the company.” The exchange, open since 2010, reportedly lost 744,408 bitcoin, valued at roughly $425 million based on current exchange rates. Mt. Gox’s closure follows a series of events that began 23 February when CEO Mark Karpeles resigned from the Bitcoin Foundation board. The company abruptly suspended trading today citing “unusual activity.” The website was taken down in the following hours. Six other bitcoin exchanges—Coinbase, Kraken, Bitstamp, BTC China, Blockchain and Circle—issued a statement that read in part, “This tragic violation of the trust of users of Mt. Gox was the result of one company's actions and does not reflect the resilience or value of bitcoin and the digital currency industry.” (Reuters)(Associated Press @ San Francisco Chronicle)(WIRED)