The Federal Bureau of Investigation hasn't found any evidence to suggest the hacker or hackers who successfully penetrated the computer system at JP Morgan scored any similar successes against other big US banks, according to four people close to the investigation.

The government investigates multiple computer security threats against banks on a constant basis, but so far hasn't found anything linking the Chase attack-which was first detected about two months ago and which officials have described as significant and egregious-to any similar type of penetration against other banks.