A Russian hacker pleaded guilty on Monday to helping steal the data of more than 80 million clients of JPMorgan Chase and other financial institutions, according to Bloomberg. Andrei Tyurin reportedly admitted to taking part in what may be the largest cyber attack in corporate history, stealing customer information from 12 financial firms in a scheme that aimed to manipulate stocks that the hackers were invested in for profit. Part of Tyurin’s plea deal, submitted in U.S. District Court in Manhattan, involves prosecutors recommending 15 to 20 years behind bars and Tyurin forfeiting more than $19 million. He is set to be sentenced at a later date.

Tyurin was extradited to the U.S. in 2018 after being found in Georgia. While U.S. intelligence reportedly had evidence that Russia sought to recruit Tyurin, authorities determined the attack was not a state-sponsored but the work of an independent criminal enterprise. The scheme’s alleged mastermind was arrested at his Tel Aviv, Israel, home in 2015.