Back in 2016, 119,756 Bitcoin (BTC) was stolen from the Bitfinex crypto exchange. Some of the coins have continued to move between wallets over the years, including as recently as Monday.

Blockchain data shows that an unknown crypto user has moved 270.97974 Bitcoin from a wallet associated with the hack. The sum is worth roughly $5.2 million at time of publication.

The address 1GytseWXyzGpmHkcv9uDzkU9D8pLaGyR5x, which is believed to be associated with the hack, shows less than 0.001 BTC remaining. The BTC were sent to a previously unknown Bitcoin address, 3MyXrfSg7JFXLa7bD6YF1GnomEr8EXYRnx, which holds only the transacted amount.

The hackers responsible for the breach have moved only 1%–2% of the stolen funds during the four-year interim since the theft took place. Their HODLing strategy appears to be paying off — the haul was worth a mere $72 million at the time, but is now valued at around $2.3 billion.

In June, the thieves transferred 736 BTC from the hack to the Russian darknet marketplace Hydra, with some coins actually ending up back at Bitfinex. Likewise, someone transferred 3,503 BTC from addresses associated with the 2016 Bitfinex hack back in July as well. Coins also moved in October, with 2,900 BTC changing wallets. Various amounts of Bitcoin from the hack have also moved on multiple other occasions.

98% of the stolen funds have remained untouched for four years, however. This may suggest that the hackers have faced difficulties laundering the digital assets as authorities enforce stricter regulations. 

Turner Wright contributed to this article.