On January 26, 2018, Coincheck announced hackers stole 523 million NEM coins from its internet-connected hot wallet, which lacked adequate security controls. The exchange began reimbursing approximately 260,000 affected users.

Unidentified assailants stole 523 million NEM coins (about $534 million) from the exchange's hot wallet. According to Coincheck, NEM coins are kept on a single-signature hot wallet instead of a more secure multi-signature wallet, and the stolen coins are confirmed to be Coincheck customers.