The UK Court of Appeal has ruled that Mastercard and Visa may appeal a High Court judgment holding that the card networks' interchange fees charged to merchants breach competition law.

The decision, handed down by the Court of Appeal, grants the two payment giants permission to challenge a ruling that had found their multilateral interchange fees — the charges levied on retailers each time a customer pays by card — infringed UK and European antitrust rules.

The underlying litigation pits major UK retailers against the card schemes. Merchants have long argued that the fees, set collectively by Mastercard and Visa rather than negotiated individually, inflate their costs of accepting card payments. The High Court had sided with the merchants, finding the fee-setting arrangements restricted competition.

The Court of Appeal's willingness to hear the case signals that the legal questions at stake — including how interchange fees should be assessed under competition law and what standard applies to platform-type pricing arrangements — remain genuinely contested rather than settled.

What it means for practitioners

For claimant firms acting for retailers, the appeal introduces delay and uncertainty into damages claims that flowed from the High Court finding. Any merchant claims for repayment of interchange fees, including collective proceedings before the Competition Appeal Tribunal, will now have to account for the possibility that the liability finding could be overturned or narrowed. Defendants' counsel, meanwhile, gain a second opportunity to argue that the fees reflect the efficiencies and two-sided market dynamics of card payment systems. Competition litigators on both sides should diarise the appeal timetable and consider how potential outcomes — affirmation, reversal, or a remittal — would affect quantum arguments and settlement leverage in the wider wave of UK interchange fee litigation.