Barclays suspended six traders in connection with an investigation into alleged wrongdoing in foreign exchange trading on Friday, sources with knowledge of the situation told CNBC.
Barclays declined to comment on the report, which comes after the Financial Times reported that RBS had suspended two traders in its foreign exchange division amid an ongoing probe.
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In its third-quarter earnings on Friday, RBS said that investigations relating to foreign exchange trading activities was a possible factor that could affect future results. It added that it was reviewing its forex trading procedures.
Regulators launched a formal investigation into the market after media reports back in June highlighted alleged wrongdoing in foreign exchange trading.
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The U.S. Justice Department, the U.K.'s Financial Conduct Authority (FCA), Switzerland's Financial Market Supervisory Authority, the Monetary Authority of Singapore and the Hong Kong Monetary Authority have all confirmed their involvement in the probe.
Every day, $5.3 trillion is traded in foreign exchange markets, according to the Bank of International Settlements, with around 41 percent of trades being processed through sales desks in the United Kingdom and 18 percent in the U.S. Deutsche Bank is the world's leading foreign exchange house, according to a Euromoney, with 15.18 percent. Second-placed Citi has a market share of 14.9 percent with Barclays and UBS just behind.