Ellie K writes Bitcoin exchange MyCoin has vanished — leaving $387 million in investor funds unaccounted for. MyCoin is a Hong Kong-based virtual currency trading exchange. Bitcoin exchanges are no stranger to controversy. Mt. Gox closed in February 2014, filing for bankruptcy and leaving investors approximately $500 million out of pocket. Others were 'cyberattacked' including Flexcoin, Poloniex and Bitcurex.