Regulators are investigating Credit Agricole, HSBC, Deutsche Bank and Societe Generale over the Libor manipulation scandal that claimed the boss of British bank Barclays, the Financial Times reported Thursday.
Citing sources close to the probes, the FT said regulators were examining evidence of links between traders at all four banks and Barclays' former trader Philippe Moryoussef.
US futures regulator the Commodity Futures Trading Commission recently accused an unnamed trader of having "orchestrated an effort to align trading strategies among traders at multiple banks".
According to the business publication, this trader was former euroswaps trader Moryoussef.
Britain's financial regulator the Financial Services Authority (FSA) is investigating seven institutions over the scandal, a senior official told lawmakers on Monday.
Tracey McDermott said the probe involved "not only British banks."
Barclays was fined £290 million ($452 million, 360 million euros) after admitting attempting to manipulate the Libor and Euribor rates between 2005 and 2009.
Libor (London Interbank Offered Rate) is a flagship London instrument used as an interest benchmark throughout the world, while Euribor is the eurozone equivalent.
The rates play a key role in global markets, affecting what banks, businesses and individuals pay to borrow money.