$70M Bitcoin missing

Photo: The Canadian Press

The frenzy surrounding bitcoin amped up further Thursday as the virtual currency soared above $15,000 for the first time, just days before it starts trading on major U.S. exchanges.

At the same time, there are fresh concerns about the security of bitcoin and other virtual currencies after NiceHash, a company that mines bitcoins on behalf of customers, said it is investigating a breach that may have resulted in the theft of bitcoin valued at about $70 million.

Research company Coindesk said that a wallet address referred to by NiceHash users indicates that about 4,700 bitcoins had been stolen. NiceHash said it will stop operating for 24 hours while it verifies how many bitcoins were taken. Wallet is a nickname for an online account.

There was no immediate response from NiceHash to an emailed request for more details.

Slovenian police are investigating the case together with authorities in other states, spokesman Bostjan Lindav said, without providing details.

The hack occurred just as the trading community prepares for bitcoin to start trading on two established U.S. exchanges. Futures for bitcoin will start trading on the Chicago Board Options Exchange on Sunday evening and on crosstown rival CME Group's platforms later in the month.

The price of bitcoin has jumped in the past year, particularly so in recent weeks. On Thursday it surged to over $15,000, up $1,300 in less than a day, according to Coindesk. At the start of the year, one bitcoin was worth less than $1,000.

Bitcoin is the world's most popular virtual currency. Such currencies are not tied to a bank or government and allow users to spend money anonymously. They are basically lines of computer code that are digitally signed each time they are traded.