A Russian man extradited to the US has been charged with hacking into US banks, brokers and financial news firms.
Andrei Tyurin is accused of being part of a gang that conducted an "extensive hacking" campaign from 2012-15.
One of the most high-profile victims was JP Morgan Chase, which lost data on 80 million customers.
Mr Tyurin was extradited to the US from Georgia to face charges of wire and bank fraud and computer hacking.
In total, the gang behind the attacks on US financial institutions is believed to have stolen information on more than 100 million Americans, said the Department of Justice (DoJ) in a statement.
The DoJ claims that Mr Tyurin was a key member of the hacking gang and carried out "massive" attacks at the behest of other members. Numerous technical tricks were used to penetrate accounts, said the DoJ indictment, including the well-known Heartbleed bug which can give attackers access to sensitive data stored in a computer's memory.
As well as gaining illicit access to customers' accounts, the group is believed to have used its list of stolen contacts as a way of artificially inflating the value of companies in which members owned stocks.
Mr Tyurin is believed to be one of the last members of the gang which carried out the attacks. Four other men have already been arrested and charged for their alleged involvement.