Visa and Mastercard face a proposed 5 billion pound UK class action over interchange from about one million businesses

Law firms Harcus Parker and Hausfeld filed collective proceedings applications at the UK Competition Appeal Tribunal on 26 October 2026, targeting multilateral interchange fees on Visa and Mastercard consumer debit, credit and prepaid card transactions between October 2020 and October 2026. If the tribunal certifies the claim, an estimated one million UK businesses, charities and organisations with revenue below 100 million pounds would be included on an opt-out basis, while larger businesses would have to opt in.

Reporting attributes a figure of roughly 5 billion pounds in total compensation to sources close to the case rather than to an official valuation. Mastercard called the claim speculative; both schemes dispute its basis.

This is the broadest UK interchange claim yet by covered merchant count, and it runs on top of a separate registered claim for about 126,000 businesses over post-Brexit fees on EEA-issued cards. The Competition Appeal Tribunal already found in June 2025 that certain consumer and commercial card MIFs restricted competition, so the open question is quantum and pass-on rather than liability in principle.

A certified opt-out class of a million merchants turns UK interchange from a regulatory file into a balance-sheet item for both schemes.

The certification hearing, whether the two UK claims are case-managed together, and whether the schemes change UK MIF levels before quantum is decided.

• paymentexpert.com