The credit card providers have been accused of charging shops excessive fees to process card transactions, which resulted in retailers being forced to pass on these costs in inflated prices for shoppers.
Up to 46m MasterCard customers could be entitled to damages under the lawsuit. The allegations relate to a 16-year period from 1992 to 2008.
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The action follows a 2014 ruling from the European Court of Justice which found MasterCard had charged excessive fees to store owners. Lawyers from Quinn Emanuel, who are bringing the case forward, said because “MasterCard’s fees have already been found to be illegal … this ‘follow-on’ claim need only prove the damage consumers suffered as a result of MasterCard’s anti-competitive behaviour.”
MasterCard rebuffed the claims, stating: “We continue to firmly disagree with the basis of this claim, and we intend to oppose it vigorously.”
Former financial services ombudsman Walter Merricks is working with lawyers on the claim, which will also be a test bed for new laws which mean all affected customers are automatically eligible for compensation, without having to opt-in to legal action.