Officials looking into investors targeting big US banks to make 'easy money'

First Republic Bank was one of several US companies that had millions wiped from its share price. (AP Photo: Godofredo A Vásquez)

US authorities are now looking into whether big investment firms are targeting, or attacking, otherwise healthy banks to make a profit.

Federal and state officials are assessing whether "market manipulation" caused the recent volatility in banking shares, Reuters is exclusively reporting.