But later on Wednesday, blockchain analytics firm Elliptic said hackers had returned $258 million worth of the stolen digital coins to Poly Network, after a plea from the platform urging the hackers to return the stolen crypto to its rightful place.

Earlier, Poly Network announced the hack on Twitter and posted details of digital wallets to which it said the money was transferred, urging people to blacklist tokens from those addresses and said it planned to take legal action.

Despite nearly half of the stolen crypto being returned, the theft is one of the biggest ever in cryptocurrency markets, which in 2018 saw the $530 million heist from Tokyo-based exchange Coincheck and the 2014 collapse of the Mt. Gox exchange, also based in Tokyo, after it lost half a billion dollars in bitcoin.

The latest attack comes as losses from theft, hacks and fraud related to decentralized finance hit an all-time high, raising the risk of both investing in the sector and of regulators looking to crack down on it.

Poly Network did not immediately respond to a request for more detail about the incident. It was not immediately clear where the platform is based, or whether any law enforcement agency was investigating the heist.