Virtual currencies including Bitcoin, Monacoin and Bitcoin Cash were stolen from the exchange’s hot wallet, with 4.5bn yen’s worth ($40m) belonging to Zaif customers.
The incident occurred over a two-hour period on September 14, with server issues detected three-days later and the authorities notified shortly after. The firm is withholding precise details of the attack while the authorities investigate.
Parent company Tech Bureau has reportedly already been hit with two business improvement orders this year and was subsequently forced to sign an agreement with investment group Fisco that will see the firm receive 5bn yen to help replace the lost coins, in exchange for majority ownership.