Filing deadlines - the CAT pounces

In September 2025, the Competition Appeal Tribunal (CAT) issued guidance note 1/2025 on filing deadlines. The language was forceful – calling out parties who fail to observe filing deadlines or who seek an extension of time very shortly before the expiry of the deadline without providing adequate explanation of why an extension is necessary. "Failure to file by the deadline causes inefficiencies," it said.

It also highlighted the disruptive nature of the practice of leaving it to the last minute before the expiry of a deadline to seek an extension of time, "in expectation of receiving the documents by the required time, the Registry staff will usually have made arrangements, often outside normal working hours, for the immediate processing and onward transmission of those documents to Tribunal members, who themselves will usually be working to a tight timetable". With budgets tight the CAT is seemingly reluctant to incur any unnecessary overtime costs.

Promising to keep "a close watch on these matters", it suggested that in some cases the tribunal may require a senior member of the relevant legal team to explain in writing why the "situation" has arisen.

Two recent decisions bear out this new harder line approach to deadlines.

CAT finds no justification for the delay for late entities opting-in after the deadline

In early March, the tribunal made a ruling in the Commercial and Interregional Card Claims (interchange fees) collective proceedings[1] in favour of Visa and Mastercard in relation to their application challenging the inclusion of various legal entities named in the opt-in class register.

In the application, the tribunal was asked, by the class representative, in relation to any entities the tribunal considered had not validly opted in, to provide permission for those potential class members to opt in late under Rule 82(2) of the Tribunal Rules. In a unanimous decision, it declined to do so.

Some entities had missed the deadline by only a few hours or due to an administrative error but then waited months to bring an application for permission under Rule 82.

Regarding the applications to opt in late, the tribunal noted that these applications were not made promptly, with there being no good reason for the delay. The tribunal also repeatedly referred to the fact that there was no witness evidence about the reason for failing to opt in properly or the delay.

"Compliance with any Tribunal deadline is mandatory, not discretionary. That is all the more so for the important process of identifying the class for the purpose of opt-in collective proceedings. The process to specify a fixed date for opting in serves the important purposes of creating certainty in the proceedings and providing the defendant with an understanding of its legal exposure. It cannot be approached with the casualness displayed in the process in these proceedings."

The tribunal focused on the impact on the integrity of the opt-in regime which would be undermined if parties do not take the opt-in deadline seriously and if they do not feel obliged to seek to address any problems promptly and with proper explanations of the reasons for the problem.

No "exceptional" circumstances to allow grant of extension of time in CAT

In Aramark v CAT (Case: 1766/4/12/26), a decision handed down on 10 March 2026, the applicant Aramark was refused its request for an extension of time under Rule 25(3) of the Competition Appeal Tribunal Rules 2015. The result is that the Competition and Markets Authority's (CMA) order, for Aramark to divest its 90% stake in Entier, stands.

By way of background, in January 2025 Aramark acquired 90% of the issued share capital of Entier. In response, the CMA, launched a merger inquiry into the transaction. Following its investigation the CMA decided, in its final report, that the acquisition had created a relevant merger situation that has resulted or may result in a substantial lessening of competition. The remedy, it concluded, was the divestment of Entier.

In January and February of 2026 Aramark advised the CMA that it was considering and then intended to appeal this decision. In error, Aramark's legal team worked to an appeal deadline of 5pm on 13 February 2026. The CMA's deadline, under the CAT Rules and Tribunal's Guide, for filing an application for review under s120 of the Enterprise Act 2002 was 5pm on 12 February 2026.

Despite Aramark's legal team's apparent good faith misinterpretation of the rules, it was the tribunal's decision that it had no power to grant an extension of time under Rule 25(3) unless it was satisfied that the circumstances were exceptional.  It reasoned – this was a retrospective application, intended to cure a failure to comply with the statutory time limit – an obvious first question was why the applicant had not met the deadline. The tribunal noted that no full, specific and acceptable account of the factual position, supported by a statement of truth, was provided in support of the application.

Despite the applicant advancing several arguments justifying an extension of time – including the lack of prejudice suffered by the CMA, the severity of the consequences for Aramark, and the fact that the error was caused by the solicitors, not Aramark, the tribunal did not find that there were truly "exceptional" circumstances.

Key takeaway

Per paragraph 2. of guidance note 1/2025: "When the Tribunal sets a filing deadline… it expects that deadline to be met."

[1] Commercial and Interregional Card Claims I Ltd. (CICC I) v. Mastercard Inc. and others, Commercial and Interregional Card Claims II Ltd. (CICC II) v. Mastercard Inc. and others, Commercial and Interregional Card Claims I Ltd. (CICC I) v. Visa Inc. and others, and Commercial and Interregional Card Claims II Ltd. (CICC II) v. Visa Inc. and others, case numbers 1441/7/7/22, 1442/7/7/22, 1443/7/7/22 and 1444/7/7/22