By Nate Raymond
NEW YORK (Reuters) - The U.S. Justice Department on Tuesday brought charges against three former traders at JPMorgan Chase & Co <JPM.N>, Citigroup Inc <C.N> and Barclays Plc <BARC.L> arising from a global probe into the manipulation of foreign exchange prices at major banks.
Richard Usher, formerly of JPMorgan, Rohan Ramchandani, formerly of Citigroup, and Chris Ashton, formerly of Barclays, were charged in an indictment filed in federal court in Manhattan with conspiring to restrain trade.
The case came after JPMorgan, Barclays, the Royal Bank of Scotland <RBS.L> and a Citigroup unit pleaded guilty in May 2015 to conspiring to manipulate currency prices, agreeing at that time to pay more than $2.5 billion in criminal fines.
Those plea deals contributed to the more than $10 billion some of the biggest banks in the world have agreed to pay to resolve U.S. and European probes into the manipulation of foreign exchange rates.
The indictment said that from 2007 to 2013, Usher, Ramchandani and Ashton participated with other euro-dollar traders belonging to an electronic chat group called "The Cartel" to suppress competition in the foreign currency exchange spot market.
Usher, JPMorgan's former chief currency trader, and Ramchandani, Citigroup's ex-head of European spot foreign exchange trading, left both banks in 2014. Ashton, Barclays' former global head of spot trading, was a trader at the British bank until 2015. All three traders were based in the United Kingdom, according to court papers and their lawyers.
The U.S. charges came after the UK Serious Fraud Office (SFO) in March said it had closed its own investigation without any individuals being charged, saying there was "insufficient evidence for a realistic prospect of conviction."
Lawyers for Ramchandani and Usher in statements criticized the Justice Department's decision to bring charges after the SFO had decided not to do so.
"The UK authorities looked at the matter very carefully and concluded that there were no offences, and we continue to believe that Mr. Usher has done nothing wrong," said Jonathan Pickworth, a lawyer for Usher.
Stephen Pollard, a lawyer for Ramchandani, said his client had been investigated for over 18 months in the UK and was not prosecuted.
"It is unacceptable for the American DoJ to by-pass the SFO decision and seek to prosecute conduct undertaken on British soil by British citizens where the British regulators have confirmed there was no criminal offense," Pollard said in a statement.
A lawyer for Ashton declined to comment.
To date, three other individuals have faced U.S. charges stemming from the foreign exchange probe.
Last week, a former trader at Barclays and BNP Paribas SA <BNPP.PA>, Jason Katz, pleaded guilty to participating in a price-fixing conspiracy, becoming the first person to admit criminal wrongdoing in the probe.
In July, an HSBC Holdings Plc <HSBA.L> executive, Mark Johnson, was arrested and charged along with a former executive for participating in a fraudulent scheme involving a $3.5 billion currency transaction. Johnson has pleaded not guilty.
The case is U.S. v. Usher et al, U.S. District Court, Southern District of New York, No. 17-cr-19.
(Reporting by Nate Raymond in New York; additional reporting by Jamie McGeever in London; Editing by Chizu Nomiyama and Meredith Mazzilli)