Tokyo-based Coincheck lost $532 million in digital assets (nearly $420 million in NEM tokens and $112 in Ripples) The exchange abruptly froze most of its services, including deposits, withdrawals and trade of almost all cryptocurrencies, except Bitcoin. The exchange has already reported the incident to the law enforcement authorities and to Japan’s Financial Services Agency to investigate the cause of the missing tokens. In 2014, Mt Gox, one of the largest bitcoin exchanges, filed for bankruptcy after admitting it had lost $450 million in Bitcoins.
Source: https://thehackernews.com/2018/01/coincheck-cryptocurrency-heist.html