"Bybit is solvent even if this hack loss is not recovered, all of clients assets are 1 to 1 backed, we can cover the loss," the company's chief executive officer Ben Zhou said in a post on X.
Bybit said its security team, along with forensic experts, was investigating the incident, adding: "We have reported the case to the appropriate authorities.".
He said the company received more than 350,000 withdrawal requests following what he described as "the worst hack in history", adding: "ALL withdraws have been processed.".
The Dubai-based Bybit exchange said an attacker gained control of an Ethereum wallet and transferred its holdings to an unidentified address.
The firm, which has more than 60 million users worldwide, said no other wallets were affected and withdrawals were proceeding normally.
