Judgment (CPO Variation)

The Tribunal’s judgment in relation to an application by the Defendants for the CPO to be varied to exclude from the opt-out class all merchants with Gross Merchandise Sales (GMS) of over £10 million on the UK Amazon Marketplace over the Relevant Period, on the basis that these excluded merchants should instead pursue collective proceedings on an opt-in basis (the Application). 

At an oral hearing held on 7-8 September 2026, the Tribunal determined that the Defendants’ application would be refused, with reasons to follow in writing. This judgment sets out the Tribunals’ written reasons. 

Firstly, the Tribunal considered whether the Defendants’ application amounted to an abuse of process. The Tribunal noted that the appeal in Evans v Barclays Bank Plc & Ors. (Evans) was pending before the Supreme Court at the time of the certification hearing in these proceedings, and that the Defendants had at the time of the certification hearing expressly reserved their right to make further submissions on the opt-in/opt-out question once the Supreme Court issued its judgment. In those circumstances, the Tribunal considered that the Application did not amount to an abuse of process insofar as the submissions advanced were based on the Evans Supreme Court judgment ([2025] UKSC 48).  

Secondly, the Tribunal considered Rule 79(3) of the Competition Appeal Tribunal Rules 2015 as it applies to the determination of whether collective proceedings should be opt-in or opt-out. The Tribunal noted that Rule 79(3) provides for the Tribunal to make a broad evaluative assessment and that this assessment is expressly not confined to considerations of strength and practicability, although these two factors are clearly significant. The Tribunal considered the following factors:

1. The strength of the claims. The Tribunal held that the concept of the strength of the case involves a spectrum, and that the Supreme Court confirmed in Evans that the weaker the case, the more that factor weighs in favour of opt-in certification, whereas the stronger the case, the less the leveraging effect of opt-out proceedings is unfair, having regard to the objective of collective proceedings in enabling access to justice. The Tribunal’s assessment, which was made on a very provisional basis, was that for four of the five heads of abuses alleged in these proceedings, the claims are strongly arguable with a reasonably good prospect of success.
2. Practicability. The Tribunal considered the Supreme Court’s decision in Evans. It rejected the Defendants’ submission that Evans established that when it is practicable (on an objective basis) for class members to opt in, then irrespective of the merits of the claims, the proceedings should normally not be certified on an opt-out basis. Furthermore, the Tribunal did not accept that the fact that a merchant had a GMS of over £10 million meant it was practical for that merchant to opt in to the proceedings. Instead, it found that many such merchants may be relatively small companies for whom it may not be reasonably practicable to make an informed decision about whether to participate in the claim or not. The Tribunal also found that the Defendants’ proposed cut-off between the opt-in and opt-out class was entirely arbitrary, and that unlike in Evans, the main core value of the claim in these proceedings lies in the mass of more modest claims, not in a small number of very large claims.

3. Other relevant factors. The Tribunal also had regard to: 

   (i) the fact that these proceedings have been progressing on an opt-out basis since late November 2025 and that a variation of the CPO at this stage, with a view to a new application for a separate or subclass, would cause disruption and significant delay;

   (ii) the fact that a delay in these proceedings would also cause further delay to the Hammond action (with which the Stephan action is being jointly case managed); and 

   (iii) the concern set out in the Tribunal’s CPO judgment ([2025] CAT 42) that independent merchants may feel intimidated by engaging directly in litigation with the Defendants.