The FBI and Secret Service are working together to investigate cyberattacks against several U.S. banks.
Bloomberg.com reports Russian hackers attacked the U.S. financial system earlier this month. The attack resulted in the loss of many gigabytes of data.
Some investigators believe the attack came as a retaliation against the U.S. sanctions against Russia.
The New York Times said data and account information was stolen from JP Morgan Chase and at least four other firms.
It is unknown whether the hackers were financially motivated or conducting an espionage campaign.