The hackers behind the recent exploit of several pools on the decentralized exchange Curve Finance have returned approximately 73% of the stolen crypto assets, accounting for about $52.3 million.

Blockchain security firm PeckShield revealed Monday that Curve Finance lost $73.5 million in the hack. With the amount recovered so far, the exchange is looking to recoup the remaining $19.7 million.

Curve Finance Recovers $52M of Stolen Assets

Eight days ago, Curve Finance suffered a reentrancy attack that affected four pools using a certain version of the Ethereum Virtual Machine smart contract programming language Vyper. The hack extended to several decentralized finance protocols, including Metronome, Alchemix, and Ellipsis.

On August 3, Curve, Metronome, and Alchemix contacted the attackers via an on-chain message, offering a 10% bug bounty in exchange for the return of 90% of the stolen assets. The platforms promised to cease pursuing the case with law enforcement if the assets were returned before 08:00 UTC on August 6.

Failure to comply with the proposal would force the protocols to offer a public and give the reward to whoever identifies the hackers in a way that leads to their conviction in court, per the message.

Less than 24 hours after the proposal, one of the exploiters sent 4,819 ether (ETH) worth $8.9 million to Alchemix after asking the protocol team to confirm their wallet address to avoid making a wrong transfer.

Curve Extends Bounty for Remaining Funds

Over the weekend, the attackers returned most funds to the affected protocols. PeckShield explained that Alchemix received all of its lost assets, amounting to $22 million in ETH and alETH, while JPEG’d, another affected protocol, received $10.1 million in WETH.

In addition, white hat hackers returned the $13 million taken from Alchemix during the exploit, and Metronome received $1.4 million, adding to the $5.4 million returned by c0ffeebabe.eth on August 31. It is worth noting that JPEG’d and Metronome hackers returned 90% of the funds, keeping the remaining 10% as Curve offered.

Since the deadline has passed, Curve has extended a 10% bounty for the remaining funds to the public as promised. The exchange noted that the offer would end if the exploiter chose to return the funds in full.