UK merger control: Policy updates from the Competition and Markets Authority

The Competition and Markets Authority (CMA) is continuing with its overhaul of merger control in the UK, responding to the government’s growth edict by further embedding the “4Ps” – pace, predictability, proportionality and progress – in its work.

We unpacked the 4Ps in this blog post.

Recent developments include a consultation on revised merger remedies guidance, updated procedures for the Mergers Intelligence Committee (MIC), and broader process reforms set out in the CMA’s updated jurisdictional guidance.

Remedies consultation

In March 2025, the CMA launched a review of its approach to remedies in merger cases, and, following feedback received, is now consulting on proposed changes to its merger remedies guidance. The consultation closed on 13 November.

The proposals indicate something of a shift in the CMA’s mindset. A key change is an express acknowledgment that behavioural commitments can be effective remedies in some cases and clarifying that every remedy will be assessed on its merits, regardless of which “type” of remedy it is. This is a welcome departure from the previous guidance, in which the CMA expressed a strong preference for structural (divestment) remedies. However, the draft guidance indicates that the CMA may retain some preference for structural remedies, which the CMA considers are usually more clear-cut than behavioural remedies.

Other proposed revisions to the guidance are welcome, particularly those aimed at driving earlier engagement on remedies between the parties and the CMA, in particular at the end of a phase 1 review. The statutory timeframes which apply at this point are tightly compressed, meaning it is challenging in practice for the parties to propose more complex remedies after the CMA has issued its phase 1 decision, and equally challenging for the CMA to assess whether those remedies will be effective in addressing the competition issue identified. Earlier engagement on a without prejudice basis should open the door, at least in principle, to the possibility of more behavioural remedies being considered at phase 1. However, it remains to be seen how these changes are implemented in practice, and whether the new guidance truly heralds a softer, more flexible approach from the CMA with a view to getting deals through wherever possible.

Updated guidance on mergers jurisdiction and procedure

On 28 October 2025, the CMA published its updated jurisdiction and procedure guidance (CMA2) and a new template Merger Notice, following consultation on the draft which took place over the summer.

The key changes include clarification on the scope and application of the “material influence” and “share of supply” tests which form part of the CMA’s jurisdictional thresholds. These tests afford the CMA a great deal of flexibility in determining whether it has jurisdiction to review a merger and had been criticised for causing a high degree of uncertainty for parties. The changes implemented by the CMA should result in greater predictability (one of the 4Ps), but more change may be coming, as the UK government separately announced that it plans to consult on legislative changes to these tests.

The updated guidance also introduces KPI commitments to ensuring that the pre-notification stage of a merger investigation will be limited to 40 working days, down from a current average of 65 working days; and to clearing “straightforward” phase 1 cases within 25 working days (within the 40 working day statutory deadline). This is clearly aimed at delivering the “pace” part of the 4Ps.

Turning to the “process” element of the 4Ps framework, the changes are also aimed at achieving better and more extensive engagement between the merger parties and the CMA, with early “teach-ins” becoming a regular part of the process, and additional informal update calls with the parties.

Finally, the updated guidance confirms the CMA’s new approach to global deals. The CMA is adopting a “wait and see” approach in cases where a transaction is subject to review by other international regulators, and where remedies agreed in other jurisdictions would be likely to address competition concerns in the UK. This supports the “proportionality” plank of the 4Ps.

Updated guidance on the Mergers Intelligence Committee

Also on 28 October 2025, the CMA published updated guidance on its mergers intelligence function. The UK’s merger control regime remains voluntary for the most part, meaning that parties are not obliged to inform the CMA about a merger, even if the CMA would have jurisdiction to review it. However, the CMA has a duty to track merger activity in order to consider whether any merger might give rise to a substantial lessening of competition (SLC). The CMA’s MIC identifies and screens unnotified mergers. The MIC is highly active and meets weekly to consider potential transactions for review.

To mitigate the risk of the MIC finding out about an unnotified deal and sending an enquiry letter, parties have the option of submitting on a confidential basis a five-page briefing paper to the MIC, setting out information about their transaction and explaining why it does not result in any SLC. For a suitable case, where it’s clear that the CMA does not have jurisdiction to review the transaction, or that a SLC will not arise, this is a very useful and important tool. A response from the CMA indicating that it does not have any further questions at the time gives the parties sufficient certainty on the CMA’s views to allow them to complete with confidence.

The updated guidance on the MIC provides some clarifications on engagement with the MIC and aligns the MIC with the changes made in the jurisdictional and procedural guidance. Importantly, the updated guidance confirms that briefing papers must be no more than five pages in length, reiterating that the briefing paper process is an initial screening mechanism. Briefing papers which are longer than five pages will be rejected and may indicate, in practice, that the case is perhaps not an appropriate candidate for the briefing paper process.

Comment

These changes are overall likely to be welcomed by business and investors, as the previous UK merger control processes could sometimes feel highly burdensome and inflexible when compared with the merger control regimes of other jurisdictions. But the CMA’s greater focus on pace, in particular, will come at a cost. The CMA has made it clear that achieving the 4Ps is a shared endeavour and the parties must be prepared to meet deadlines to CMA information requests and make focused submissions to enable the CMA to meet their targets. Transaction planning should include consideration of UK merger control risk from the outset, and careful planning for CMA engagement and strategy.

The CMA has had a busy time of late, launching a major consumer protection campaign and enforcement action focusing on online pricing practices, and responding to the Chancellor’s invitation to open a market study into private dentistry. The 4Ps mantra continues to drive the CMA’s strategy and we expect this to continue.