Barclays (BARC.L), Royal Bank of Scotland (RBS), Citigroup (C), and JPMorgan (JPM) are among several banks that have been fined €1.07bn (£935m) by the European Commission for colluding on currency foreign exchange trading strategies.
The European commission said the banks, which also include Citigroup, JP Morgan and MUFG (Mitsubishi UFJ Financial Group), formed two cartels to manipulate the spot foreign exchange market for 11 currencies, including the United States dollar, the euro and the pound.
The "Three Way Banana Split" cartel, made up of traders at UBS, Barclays, RBS, Citigroup and JP Morgan, was handed a fine totalling 811.2 million euros.
The European Commission said Thursday that investigators found that some bank employees in charge of spot trading in 11 currencies "exchanged sensitive information and trading plans".
The Essex express 'n the Jimmy chatroom was so-called because all the traders but "James" lived in Essex and met on a train to London.
Other chatroom names included the "Three way banana split" and "Two and a half men".
Barclays, RBS and MUFG Bank, formerly the Bank of Tokyo-Mitsubishi, were fined for its part in the Forex-Essex Express cartel, the commission said.
UBS, which escaped the latest fines, said: "This is a legacy matter where UBS was the first bank to disclose potential misconduct".
"These cartel decisions send a clear message that the commission will not tolerate collusive behaviour in any sector of the financial markets", said Vestager.
Credit Suisse was charged separately by the European Union over foreign exchange collusion past year, and a fine may yet be announced, Bloomberg reported. Former US attorney general Loretta Lynch in 2015 said the banks engaged in a "brazen display of collusion" to game markets. "This kind of behaviour has no place at the bank we are today; our culture and controls have changed fundamentally during the past ten years".
"We are committed to ensuring integrity and compliance with the regulatory authorities in every jurisdiction in which we operate, and have taken a number of measures to prevent this occurring again".
Because Barclays, RBS, Citigroup, and JPMorgan all received reduced fines for their cooperation with the investigation, they will not be able to appeal the commission's ruling. They would sometimes agree to "stand down" or stop a trading activity to avoid interfering with another trader in the group.
The 11 currencies involved include the euro, British pound, Japanese Yen, Swiss Franc, US, Canadian, New Zealand and Australian Dollars, and Danish, Swedish and Norwegian crowns.
At €311m, Citigroup's fine was the largest, followed by fines of €249m for RBS, €229m for JPMorgan, and €210m for Barclays.