Infini, a prepaid payments card issuer that offers interest on deposited dollar stablecoins, warned a hacker it had “gathered critical IP and device information” after losing almost all the value locked in its wallets.

The attacker drained $49.5 million from the Hong Kong-based neobank’s wallets, according to Peckshield. The company said only on Sunday it had hit $50 million in total value locked.

The exploit came just days after Bybit, the second-largest cryptocurrency exchange by trading volume, saw a hacker drain its ether cold wallet and make off with nearly $1.5 billion in crypto’s largest exploit.

“We are closely monitoring the address involved and are prepared to take immediate action to freeze any stolen funds if necessary,” Infini told the hacker in a blockchain transaction. “In an effort to resolve this matter amicably, we are willing to offer you 20% of the stolen assets should you choose to return the funds.”

Infini gave the perpetrator 48 hours to “facilitate a swift resolution,” and that failure to respond means it will “have no choice” but to continue its investigation in collaboration with law enforcement.

According to Cyvers, the exploit occurred after a developer who helped set up its smart contract kept admin rights over it. More than three months later, they leveraged these rights and drained the funds to a wallet funded over cryptocurrency mixer Tornado Cash.

The neobank’s founder, Christian Li, has pledged to cover the full loss from his personal funds and took responsibility for the incident.