UK Government Heralds Major Changes to UK Merger Control Regime

On 20 January 2026, the UK government announced a range of proposed reforms to the UK merger control regime.  The proposals are, once again, driven by the “primary mission” of the government – to deliver economic growth.  To that end, the merger-related reforms are intended to facilitate more targeted interventions and faster and more predictable investigations. Institutionally, the reforms are intended to increase the “accountability” of the Competition and Markets Authority (CMA) to Parliament (and, it appears, also to government), while safeguarding the “vital independence" of the CMA’s operational decision-making.

Who decides?

The headline change in the reforms is the abolition of the independent CMA panels who currently oversee Phase 2 merger investigations.  Largely replicating the model used for decision making under the CMA’s new digital markets regime, the panels will be replaced by “sub-committees” appointed by the CMA Board, comprised of senior CMA staff, CMA board members, and “expert decision makers” (appointed by the government).  As a purported check on the CMA executive, at least half of the members of a sub-committee have to be drawn from the pool of non-executive members of the CMA Board or non-CMA staff experts.

While faster and more efficient Phase 2 investigations are, of course, a good idea in principle, this model raises two potential concerns for dealmakers.

First, a key benefit of the CMA’s revised Phase 2 process (which came into force as recently as 2024) has been an increased ability for the merging businesses to “make their case” directly to CMA decision makers.  It remains unclear whether the CMA sub-committees will have the same appetite and bandwidth to absorb the wide range of detailed evidence and analysis on which complex Phase 2 cases typically turn, and to engage effectively with the merging businesses on the key issues on an ongoing basis.  While CMA sub-committees take decisions under the digital markets regime, they have a limited track record of any sort (given that the first investigations under that regime started just over a year ago).

Second, the new model means that the CMA’s executive team (under the direction of the CEO) will play a more “hands-on” role in the assessment of Phase 2 mergers, which currently benefit from a “fresh pair of eyes” provided by independent panel members.  The abolition of the independent panel removes one of the last significant constraints on the CMA executive’s decision-making power in merger cases, leaving the UK regime curiously lacking in key “checks and balances” found in most peer merger control regimes, such as access to file and “merits” review on appeal.  The proposed reforms therefore remove an important feature of the regime, designed to provide fairness for merging businesses, without any element of the reform package seeking to compensate for the loss of this procedural protection.  If the government is minded to resist any change to the standard of review that the CMA’s merger decisions will face on appeal (as its predecessor ultimately did when legislating for the UK’s digital markets regime), then the continued absence of any meaningful access to file appears particularly difficult to justify.

Clearer jurisdictional rules

The government also intends to formalise the CMA’s recent narrowing of the way in which it applies two of the less clear-cut parts of its jurisdictional tests: the “share of supply” test and the “material influence” test.  The CMA has previously used a wide range of factors to assess whether these tests are met, but will in future be tied to a “closed list” of factors that it is able to consider (effectively eliminating the possibility that the CMA could one day return to using some of the more “exotic” factors that it has used in the past). And, even with these changes, the UK regime will continue to be governed by one of the most flexible sets of jurisdictional rules found worldwide. 

Curiously, the so-called “UK nexus” test, which similarly lacks clear parameters, is excused from this tidying up exercise (perhaps because, since only being in force since the start of last year, business has yet to gain much experience with the difficulty of applying this test in practice).  The case for a clearer articulation of the UK nexus test is, in fact, arguably even stronger given that it also forms part of the test that triggers the mandatory merger reporting requirement for businesses that have been “designated” under the digital markets regime (so a difference of views about whether the test is met could, in theory, result in a significant fine, rather than “just” an unexpected call-in).

A longer runway for Phase 1 remedies

In keeping with the objective to generally close down cases as quickly as possible, the government is aiming to provide more time (and scope) to agree remedies at the end of a Phase 1 investigation. While “in principle” remedies currently have to be agreed within 10 working days of the CMA’s decision on competition issues, the government proposes to extend this period to 20 working days, to allow more time for “near misses” to be worked through.  This appears to be aimed at facilitating more complex remedies, such as carve-outs and behavioural remedies, in practice potentially expanding the toolbox of solutions available to merging businesses to address concerns.

A bigger role for government?

While the government is keen to make clear that independent competition regulation remains the “bedrock” of the UK regime, it is planning to introduce another lever to influence the CMA’s approach, giving the Secretary of State a “formal role” (e.g., consultation or approval) in authorising key guidance documents.  Notably, the government cites the CMA’s Merger Assessment Guidelines (which guide the substantive approach to investigating mergers) as an example of the kind of document that would be subject to government approval in future. 

In the past, the CMA has made changes to its own guidance to facilitate tougher enforcement against global M&A, particularly in fast-moving industries.  These changes were made without much debate outside specialist antitrust circles.  This suggestion therefore provides more oversight of the CMA in relation to potential future policy changes.  It does, however, open the door to further outside influence over the operations of an independent regulator and its approach to specific cases in practice.

Conclusion

Ultimately these reforms are some way off (given the need to pass legislation) so no immediate change should be expected.  The proposals provide further evidence of the shared desire of the CMA and the government to move more quickly and efficiently.  But while these aims are laudable (and welcome), aspects of the proposals would exacerbate existing criticisms around a lack of “checks and balances” which could, in turn, risk undermining business and legal confidence.  These concerns are likely to be hotly debated as the proposals firm up in the coming months.

To read more about our thoughts on key UK and global merger control trends in the coming year, request your copy of our Clarity in antitrust: 10 key themes in 2026 publication.