The Wall Street Journal reported, citing people close to the investigation, that U.S. regulators are widening their probe of global interest-rate-rigging by scrutinizing what they claim is a pivotal role of two UK brokerage firms in the scandal.

The Journal said that while neither firm has been accused of wrongdoing, regulators allege that some of their employees were crucial in helping specific traders rig submissions by banks of estimated borrowing costs in different currencies.

To read the Wall Street Journal story click here.