Overview
Introduction
On May 20, 2025, the European Commission (the Commission) published the proposed text, which it has adopted, of the Agreement between the European Union and the United Kingdom regarding cooperation in the application of their competition laws. This agreement is a critical supplement to the Trade and Cooperation Agreement (TCA) and the first standalone legal instrument designed to re-establish structured dialogue between UK and EU competition authorities. It should be welcomed by businesses as a first step towards better convergence between the UK and the EU in competition policy and enforcement.
It is also worth noting that the UK only has comparable cooperation arrangements (in the form of MOUs) with the US, Canada, Australia, and New Zealand.
Overview
The proposed agreement draws its legal authority from Article 361(4) of the TCA, which explicitly permits the EU and UK to conclude supplementary agreements in the field of competition. This text formalizes cooperation between the European Commission, the national competition authorities (NCAs) of EU Member States, and the UK's Competition and Markets Authority (CMA). An important feature is that for the first time in an EU cooperation agreement, the CMA may cooperate directly with individual Member State enforcement agencies.
Its purpose is defined in Article 1: to "promote cooperation and coordination" in competition enforcement "to enhance the effective enforcement" of each party's respective laws. It covers all standard competition law matters: antitrust (Articles 101 and 102 TFEU, Competition Act 1998), merger control (EU Merger Regulation, Enterprise Act 2002), and market investigations.
Importantly, the agreement does not seek harmonization. It re-establishes procedural cooperation, not substantive alignment, and is expressly constrained by each party's domestic legal framework, particularly regarding confidentiality and data protection. This means that there will be a recognized forum within which discussions can take place.
Key Features
The agreement introduces several important tools for institutional cooperation, while preserving discretion and national sovereignty. First, it creates a notification mechanism. Where enforcement activity by one authority could significantly impact the other's interests, notification is required as soon as an initial investigative step is made public. This is particularly relevant in cross-border mergers or cartel matters involving overlapping markets. In the context of mergers, given that the UK maintains a voluntary notification system, this may offer the CMA an opportunity to learn about the details of mergers notified to other Member States, in advance of any notification to it (or of a transaction being closed without it being informed).
Second, the agreement allows for voluntary coordination of enforcement activities. Authorities may choose to align timing or strategy, share insights, or even coordinate remedies, though this cooperation can be limited or withdrawn unilaterally at any stage. It provides a mechanism for the CMA to discuss economic issues or theories of harm with other Member States where, for example, the proposed transaction falls below the thresholds for notification to the Commission.
Third, the agreement codifies the principle of negative comity, requiring each side to give "careful consideration" to the other's important interests throughout the enforcement process. The most legally complex provisions, however, concern information sharing. Authorities may exchange non-public information, including personal data, provided it is allowed under applicable domestic law. In cases where parties have provided confidential business information, sharing requires either consent or legal justification under local law. Article 6 also contains limitations on onward disclosure, including a general prohibition on sharing with third countries or non-competition authorities without prior written approval.
The agreement also includes safeguards around the use of information (Article 7), specifying that shared material may only be used for the enforcement of competition laws, and, under certain conditions, may be used in proceedings involving sanctions against individuals. A breach of confidentiality or accidental misuse triggers mutual cooperation to mitigate harm (Article 9).
While the agreement is a significant step forward, it is limited in scope. There is no provision for automatic cooperation, nor any shared enforcement tools such as case management systems or joint investigation procedures. The ECN-style framework that existed before Brexit is not being revived. All cooperation remains voluntary, and each authority retains full discretion over how far it participates. The agreement also excludes state aid, foreign subsidies, and digital markets' regulation. It does not cover the public interest aspects of merger or market investigations, nor does it create obligations on procedural alignment. It is best understood as a procedural instrument.
Outlook
For practitioners, the agreement provides a clearer legal framework for managing parallel investigations and regulatory risk. In recent years, divergence in procedure and communication between the Commission and the CMA has created uncertainty for companies active in both jurisdictions. Indeed, there have been several mergers where the CMA and the Commission have come to different conclusions. These have included Microsoft/Activision Blizzard, Meta/Kustomer, and Cargotec/Konecranes. This agreement should help restore predictability, consistency, and foster the establishment of 'clear principles' with the aim of avoiding conflicts between jurisdictions.
The proposed agreement is also particularly relevant given the broad investigatory and enforcement powers exercised by both the Commission and the CMA in cartel and merger cases. These include dawn raids, formal requests for information (RFIs), the power to impose significant fines, and the ability to block transactions or impose conditions (on mergers). As mentioned above, where parallel investigations arise - such as in complex, multi-jurisdictional mergers - this agreement provides a legal basis for authorities to coordinate case timelines, avoid duplicative burdens on companies, and reduce the risk of conflicting outcomes. For businesses, this means greater procedural clarity, potentially more consistent remedies, and an opportunity to engage with both authorities through a more coordinated process, rather than navigating two disconnected investigations.
Additionally, the agreement signals renewed institutional trust, particularly given the inclusion of safeguards around data handling and personal information. While the UK remains a third country for data protection purposes, the agreement recognizes the EU's 2021 adequacy decision and reflects a pragmatic approach to sharing sensitive materials in a post-GDPR environment.
Finally, the agreement is not yet in force. It awaits formal ratification by both the UK and EU, and will enter into force on the first day of the second month after both parties complete the process. Given the typical timeline for ratification, implementation is likely in early or mid-2026. Article 11 provides for a review two years post-entry into force, which may allow for a broader or deeper cooperation model to evolve over time - depending on political and institutional appetite.
Conclusion: A Quiet but Meaningful Milestone
The UK–EU Competition Cooperation Agreement represents a pragmatic and legally significant return to structured engagement between authorities. While modest in ambition, it addresses several of the most practical problems created by the UK's withdrawal from the EU's regulatory architecture and is hopefully a first step towards more convergence and greater predictability for business. It is especially important for multinationals facing investigations or notifications in both jurisdictions. And although it does not restore the deep cooperation that once existed under the ECN, it marks an important institutional realignment after years of regulatory uncertainty. The agreement is likely to receive increased attention upon ratification. For now, its relative obscurity presents a rare opportunity for legal thought leadership - whether through commentary, client guidance, or strategic compliance advice. Law firms, in-house counsel, and scholars alike should pay close attention to this development as a model of third-country cooperation in a post-Brexit regulatory landscape.
