The hacker or hackers behind one of the biggest ever cryptocurrency heists have returned over a third of around $600 million in stolen digital coins, a blockchain researcher said on Wednesday.
Poly Network, a decentralised finance platform that facilitates peer-to-peer transactions, announced the hack on Twitter, posting details of digital wallets to which the tokens were sent.
The value of the coins in the wallets was just over $600 million at the time of the announcement, according to blockchain analysts.
Poly Network later urged the hackers to return the stolen funds to several of its digital addresses, saying it planned to take legal action.
By late afternoon around $258 million in stolen tokens had been returned, according to public blockchain records and crypto tracking firm Elliptic.
Tom Robinson, Ellipic’s co-founder, said the extraordinary move could have been prompted by the headaches of laundering stolen crypto on such a scale.
Poly Network did not respond to requests for further details about the heist or the return of the funds. It was not immediately clear where the platform is based, or whether any law enforcement agency was investigating the heist.
The size of the theft was comparable with the $530 million in digital coins stolen from Tokyo-based exchange Coincheck in 2018. The Mt. Gox exchange, also based in Tokyo, collapsed in 2014 after losing half a billion dollars in bitcoin.
The latest attack comes as losses from theft, hacks and fraud related to decentralised finance (DeFi) hit an all-time high, raising the risk of both investing in the sector and of regulators looking to shake it down.
DeFi platforms allow financial transactions, usually in cryptocurrency, without traditional gatekeepers such as banks or exchanges. The sector has boomed over the last year, with platforms now handling more than $80 billion worth of digital coins.
Poly Network allows users to swap tokens across different blockchains.