FBI probing JPMorgan hack, reports say

NEW YORK -- The FBI is investigating a hacking attack on JPMorgan Chase and at least one other bank, according to reports citing unnamed sources familiar with the matter.

A report on Bloomberg.com said Wednesday that the FBI is investigating an incident in which Russian hackers attacked the U.S. financial system earlier this month in possible retaliation against U.S. government-sponsored sanctions aimed at Russia.

The attack, Bloomberg said, led to the loss of sensitive data. Bloomberg cited security experts saying that the attack appeared "far beyond the capability of ordinary criminal hackers."

The New York Times, also citing people familiar with the matter, said JP Morgan and at least four other firms were hit this month by what it described as coordinated attacks that siphoned off huge amounts of data, including checking and savings account information.

In a statement, JPMorgan spokeswoman Trish Wexler said companies "of our size unfortunately experience cyber attacks nearly every day. We have multiple, layers of defense to counteract any threats and constantly monitor fraud levels."

Wexler did not confirm the reports and the FBI declined to comment.

The Wall Street Journal also cited unnamed sources in a less detailed report that called the attacks a "significant breach of corporate computer security."

JPMorgan is the largest U.S. bank by assets.