THREE major banks have been fined £412 million for conspiring to rig a rate used to work out the value of financial products worth billions of Euros.

HSBC, JPMorgan and Credit Agricole were given the penalty for their role in the Euribor scandal, which involved the manipulation of interest rate derivatives.

Four other banks – RBS, Barclays, Societe Generale and Deutsche Bank – were part of the same case, settling with antitrust regulators in 2013.

The cartel was said to have operated between September 2005 and May 2008, with traders using chatrooms and instant messaging to affect markets and make profit.

Yesterday JPMorgan and HSBC maintained they had done nothing wrong and said they are considering their legal options.

However, Commissioner Margrethe Vestager said: “A sound and competitive financial sector is essential for investment and growth. Banks have to respect EU competition rules just like any other company operating in the single market.”

The Commission added: “The traders’ aim was to distort the normal course of pricing components for euro interest rate derivatives.

“They did this by telling each other their desired or intended Euribor submissions and by exchanging sensitive information on their trading positions or on their trading or pricing strategies.”

HSBC said: “The European Commission’s decision relates to allegations of Euribor manipulation and related purported conduct during the course of one month in early 2007. We believe we did not participate in an anti-competitive cartel. We are reviewing the European Commission’s decision and considering our legal options.”

JP Morgan also said it was gearing up for potential legal action, stating: “We have co-operated fully with the European Commission throughout its five-year investigation. We did not engage in any wrongdoing with respect to the Euribor benchmark. We will continue to defend our position against these allegations, including through possible appeals to the European courts.”