Posting on social media, NiceHash said that "there has been a security breach involving NiceHash website" resulting in a loss of funds. NiceHash, formed in 2014, serves as a marketplace for miners to rent out their hash rate to others.
The announcement follows an hours-long outage and reports from a multitude of users that their NiceHash-associated wallets had been emptied. NiceHash previously announced that it was "under maintenance," a message that it had posted to its official website as well.
The company said in its statement:
"Importantly, our payment system was compromised and the contents of the NiceHash Bitcoin wallet have been stolen. We are working to verify the precise number of BTC taken. Clearly, this is a matter of deep concern and we are working hard to rectify the matter in the coming days. In addition to undertaking our own investigation, the incident has been reported to the relevant authorities and law enforcement and we are co-operating with them as a matter of urgency."