The CAT has set 23 October 2026 as the cut-off for new claimants joining Trial 3
Merchant Interchange Fee proceedings have been given a firm cut-off date for new claimants seeking to participate in the next major trial, after the Competition Appeal Tribunal ruled that further participation must be controlled to protect the evidence and fairness of the process.
In a ruling dated 12 August 2026, the Tribunal set 23 October 2026 as the deadline for new claimants to apply to become Host Cases under the Umbrella Proceedings Order for the purposes of Trial 3. The ruling was made by The Honourable Mrs Justice Bacon, President of the Competition Appeal Tribunal, and carries the neutral citation [2026] CAT 68.
The decision followed an application by the defendants for a much earlier cut-off of 1 September 2026. They argued that a deadline was needed to ensure that the best available evidence could be presented in an orderly manner and to give them sufficient notice of the claims they would face before Trial 3.
The claimants opposed the proposed cut-off. They argued that no deadline was necessary, or alternatively that 1 January 2027 should apply only to claimants wishing to take an active role in Trial 3.
The Tribunal rejected both proposed dates. It concluded that some form of cut-off was warranted because of the way evidence for Trial 3 is being prepared.
Trial 3 involves a sample of claimants selected by the parties’ economic experts. That selection has already taken place, based on questionnaires completed by current active and stayed claimants. Disclosure from the sample is due to take place by 23 October 2026.
The Tribunal said allowing additional claimants to become Host Cases without a cut-off could undermine the integrity of that sampling process. A material increase in new claimant entities could make the existing sample less representative, while early participation could increase the pool of evidence available to the Tribunal.
The Tribunal also placed weight on fairness to the defendants. It said future claimants should not be able to obtain the benefit of Trial 3 without being exposed to obligations to provide information or documentary evidence. Although Trial 3 will determine exemption at the level of the defendants’ card schemes on an economy-wide basis, the Tribunal noted that some evidential matters remain specific to individual merchants.
Importantly for solicitors acting for potential claimants, the cut-off applies to both active and stayed claimants. The Tribunal rejected the argument that only claimants intending to participate actively in the trial should be covered, noting that all claimants may be subject to requests for information and disclosure.
The practical deadline is therefore 23 October 2026. New claimants seeking to become Host Cases for Trial 3 must apply by that date. The Tribunal has also directed that claimants applying by 23 October must file and serve the required questionnaires within seven days of applying, unless they do so earlier.
The ruling also directs defendants to respond promptly to applications for transfer from the High Court to the Tribunal and for designation as Host Cases. When agreeing draft Host Case orders, the parties must have regard to previous orders and wording that the Tribunal has previously accepted.
Trial 3 is listed to run for ten weeks from 11 October 2027. It will determine whether the conduct can benefit from exemption under Article 101(3) TFEU and section 9 of the Competition Act 1998.
For solicitors involved in the proceedings, the immediate consequence is procedural rather than a determination of liability or exemption: any new claimant seeking to participate in Trial 3 must act before the 23 October deadline and comply with the questionnaire timetable. The Tribunal has made clear that the flexibility of the Umbrella Proceedings mechanism cannot override orderly case management or the integrity of the Trial 3 evidence-gathering process.