Sergei Potapenko and Ivan Turõgin, both 40, agreed to forfeit more than $400 million as part of their guilty pleas, per the Department of Justice.

The US Justice Department noted that two Estonian nationals have reportedly pleaded guilty to an alleged $577M cryptocurrency fraud scheme.

The co-founders of Hashflare, a crypto mining ponzi scheme that stole $577 million from hundreds of thousands of investors around the world, both pleaded guilty on Wednesday to conspiracy to commit wire fraud.

The Estonian pair also founded another venture called Polybius in 2017, a virtual currency bank that promised to pay investors dividends from profits.

The US authorities described the operation as “a massive, multi-faceted cryptocurrency Ponzi scheme that victimized hundreds of thousands of people” globally.