A Bloomberg report claims that JPMorgan Chase and "at least" four more banks in the US have been victims of a virtual attack from hackers. The data gathered from the breach could reportedly "be used to drain accounts," according to two Bloomberg sources who have been briefed on the situation by the US government. At the moment, it is unknown which other banks were affected by this, but the FBI has already opened an investigation and is currently working to find out more details. "[We are] working with the United States Secret Service to determine the scope of recently reported cyberattacks against several American financial institutions," said the FBI in a statement. Meanwhile, a different report from CNN Money notes that seven of the "top" 15 banks were on the wrong end of these attacks, per people familiar with the matter -- though such information has not been corroborated by US officials.