The UK Supreme Court hands down a significant judgment relating to the certification of a £14bn opt-out competition collective action brought against a credit card company (Merricks / Mastercard)

On 11 December 2020 the Supreme Court handed down a very significant judgment relating to the certification of a £14bn opt-out competition collective action brought by Walter Merricks against Mastercard, in respect of losses alleged to have resulted from the use of anti-competitive multilateral interchange fees. The Supreme Court largely confirmed the less restrictive approach to certification set out by the Court of Appeal when it overturned the Competition Appeal Tribunal’s (CAT’s) original refusal to grant the Collective Proceedings Order (CPO) sought by Mr. Merricks (see our previous briefing). As a result, the CAT will now need to reconsider Mr. Merricks’ application for certification of the claim against