The US charged 3 former London-based FX traders over currency rigging

US prosecutors accused three former London currency traders of arranging a "conspiracy" to rig the foreign exchange markets.

Richard Usher, who worked at both Royal Bank of Scotland and JPMorgan, Rohan Ramchandani, a former Citi banker, and Christopher Ashton, who used to be at Barclays, were charged with "conspiring to fix prices and rig bids for US dollars and euros exchanged in the FX spot market," the DoJ said in a statement.

According to the indictment, from 2007 to 2013 the traders were part of a group that called itself "the Cartel" or "the Mafia," which communicated via phone, messages and chat-rooms to collude on the setting of benchmark FX rates known as the fix.

They tried to manipulate the fix by "refraining from entering orders or trading at certain times," the DoJ said.

"Whether a crime is committed on the street corner or in the corner office, no one gets a free pass simply because they were working for a corporation when they broke the law," said Deputy Attorney General Sally Q. Yates.

"Today's indictment reiterates our commitment to holding individuals accountable for corporate misconduct."

The charges follow fines of more than $2.5 billion levied on RBS, Barclays, JP Morgan and Citi in May 2015 after the banks pleaded guilty to conspiring to rig the FX market.

"These former bank traders are alleged to have gained an unfair advantage on their counterparts by committing corporate fraud involving the manipulation of the foreign currency exchange," Paul Abbate, assistant director of the FBI's Washington office, said in the statement. "Their actions affected worldwide trading positions in the global marketplace."

The action against the three traders takes the number of individuals charged in the US FX probe to six.

In July last year, two FX executives were charged with conspiring to defraud a client by front-running, which involves trading ahead of a large order to take advantage of the upcoming price move. This month, another trader was charged with attempting to manipulate emerging market currency rates.