Overview
2025 was the year of a hard "reset" in the United Kingdom antitrust arena, starting with the sacking of the UK Competition and Markets Authority's (CMA) Chair in January, accepting of remedies in an unprecedented approval of a 4:3 telecoms merger (Vodafone / Three) in March, a voluntary settlement in a cartel case (the Homebuilders Investigation) in July, the closure of a three-year investigation (into Cloud Services) also in July and more new guidance documents than you could shake a stick at. By the end the CMA had found some renewed swagger in the consumer enforcement space, announcing eight new investigations in late December. However, by the close, the antitrust, cartel and merger dockets remained significantly lighter than in recent years, causing some to question whether the pendulum had swung too far in the other direction.
As we start 2026, we will continue to see the UK competition enforcement and merger control landscape evolve against the backdrop of a new economic and political reality (both at home and abroad). The government has set a clear direction to focus on UK issues, do a better job at engaging with business, ensure more stable and certain markets and mergers regime, and use its tools to encourage greater growth and investment. What the latter means in practice is still to be determined and direct government intervention in future mergers involving national champions or national issues has not been ruled out. A more permissive mergers regime is likely to embolden greater consolidation, leading over time to more challenging edge cases coming before the agency.
The search for a new chair of the CMA is ongoing and, once that is confirmed, this may also lead to a broader change in the senior leadership team. We also welcome a New Year with an unprecedented number of root-and-branch reviews by government and into the CMA and its statutory remit, as well as that of the United Kingdom's other regulators (including in data protection and financial services).
So, with all that in mind, for this first issue of StepAhead 2026, here are six significant UK antitrust developments to keep a close eye on in the coming months:
1. The next markets investigation
The CMA's market investigation regime enables the agency to launch in-depth investigations of markets where it believes that competition is not working well. These have traditionally focused on UK-specific markets (airports, banking, ferry services, infant formula, road fuels, etc.), which is nicely in line with the government 2025 steer to re-orient the CMA's work to focus on home markets. No triggering event is required (i.e. a suspected antitrust violation or merger) making it a wide-ranging (and unique) tool at the CMA's disposal.
The UK government instructed the CMA in November 2025 to make its next market investigation into private dentistry, which is experiencing somewhat of a similar march of roll-ups and consolidation as other markets that have caught the CMA's eye in recent years (e.g. Veterinary Services, and, previously, Care Homes) and is a mix of individual ownership, corporate healthcare providers and private equity owners. Eventual remedies could include divestiture to address concentration concerns but more likely will result in commitments to improve price transparency or, potentially, price controls. Remedies could also involve the insurers themselves.
2. The next digital markets investigation
Despite gaining expansive new powers to investigate suppliers of digital services, the CMA has not opened a "strategic market status" (SMS) investigation since last February (when it kicked off the regime with the App Stores and Search and Search Advertising (SMS) investigations, which remain ongoing). A three-year market investigation into cloud concluded in summer 2025 with a recommendation to make that the next SMS case but as yet, no announcement has been made, and it is an open question whether that is the right market that the CMA – with its new domestic focus – should be looking at. Questions of comity in this sector have recently gained heightened relevance following the European Union's announced investigations into cloud in November 2025.
It is fair to say that these new digital markets powers, which specifically target United States tech companies (turnover of £1 billion in the United Kingdom or £25 billion globally is required to qualify as an SMS candidate) could not have come at a worse time for the CMA, which is under strict orders to focus on UK-specific issues and leave global and especially US-centric markets to other regulators. The CMA (and the UK Government) have little political cover to be seen to lead in the regulation of US tech and must tread extremely carefully given that the US administration is laser-focused on perceived overreach by foreign regulators of US tech firms.
This leads to significant uncertainty about if and when there will be another SMS investigation conducted by the UK CMA's Digital Markets Unit. The possibility has even been mooted that the regime will be mothballed altogether after conclusion of the existing two investigations. This makes it an essential "one to watch" in the coming months.
3. The next antitrust or cartel investigation
2025 was also very quiet for the CMA on the antitrust and cartel side, with only one new antitrust case opened (into waste management services) and no cartel investigations announced.
It was a year for case closures, however. The CMA settled its investigation into collusion in the UK government bond auctions market in February 2025 and also accepted voluntary commitments in an investigation into suspected breaches of competition law in the homebuilding market in October 2025. The CMA also reached a settlement with Vifor Pharma in its disparagement case in May 2025. The CMA's investigation into Google's Privacy Sandbox was also closed in October 2025. The CMA also fined broadcasters for exchanging information in labor markets and 15 car manufacturers and a trade association for a long-running cartel in the end-of-life vehicle recycling sector.
We will all be watching closely to see whether this will change in 2026 and what pipeline, if any, the CMA is currently working with.
4. Reform to the jurisdictional reach of the CMA in merger cases
The UK Government has previously acknowledged the need to reform the CMA's share of supply test in merger control, which has, coupled with the "voluntary" nature of the regime, led to deep uncertainty as to where the axe will fall. The further introduction in January 2025 of a hybrid test for larger companies with significant shares in their core markets, where no increment with the target is required, has added further nervousness. The CMA's decision to investigate six AI partnerships, acqui-hires and investments as "mergers" in 2023-2025, only to clear them all unconditionally (or acknowledge that they did not qualify for investigation in the first place) further engendered confusion and uncertainty, elements antithetical to the new imperative to encourage inward investment to the United Kingdom.
Businesses will therefore welcome efforts to clarify the CMA's jurisdiction through the adoption of more brightline tests (for example, focused on turnover or transaction value) and potentially a move to a mandatory regime, which would remove the discretionary element of the UK merger control regime that has generated so much uncertainty and align the UK with other major jurisdictions.
The United Kingdom Government announced in October 2025 that it was working with CMA leadership to formulate proposals to increase certainty here, so expect a consultation soon.
5. Reform to how the CMA takes decisions on merger cases
This was trailed in a recent UK Government "action plan," which acknowledged that the CMA's panel system (where independent experts were appointed at Phase 2 to take decisions, a throwback to the days before the CMA when an entirely separate organization, the Competition Commission, undertook the Phase 2 investigation) was no longer working well. The experience in recent cases, most notably Microsoft / Activision, where the CMA had to effectively undo the decision of the panel was the most stark example of this.
These planned reforms throw the doors open to all manner of alternative approaches to decision-making, including a requirement for the CMA to prosecute merger prohibitions in court (akin to other common law jurisdictions) or – where the CMA keeps decision-making in-house – move merger decisions to full-merits appeals. We are expecting this consultation to launch in the next couple of months.
6. The outcome in Getty / Shutterstock
The anticipated merger of Getty Images / Shutterstock is an important test of the new "wait and see" mantra espoused by the CMA for global deals. This merger is currently under in-depth review by the UK CMA and US Department of Justice (among others) with the UK having identified concerns in stock photos and editorial photos in November 2025 and due to publish its interim Phase 2 report in February 2026. That report will also provide an indication of what remedies the CMA will be willing to consider.
On the face of it, this case could be a good candidate for the US to lead on concerns in regard to stock photos (a global market) with the CMA bringing up the rear with a UK-specific remedy agreed for editorial photos (a national market). However, given the somewhat unpredictable nature of current United States merger enforcement, the CMA could again be left in the invidious position of being the only international competition authority finding concerns on wider than UK markets.
The parties have already offered a structural divestiture of the affected UK business in editorial but a remedy for the CMA's global concerns could be harder to agree. With the parties holding a combined share of up to 80% of the relevant markets (on the CMA's read), the nature and scope of remedies will also be a real-world test of the CMA's new remedies guidance, published in October 2025.
Looking ahead
Here in the Steptoe London office, we will be keeping a close eye on how the CMA puts words into practice across its myriad functions and how this may impact business, positively or negatively. This is a moment of significant and fundamental change in competition enforcement in the United Kingdom but also across many other regulatory regimes and there is significant opportunity for affected businesses to have their voices heard.
If you would like to be kept informed on UK-specific antitrust developments on a more regular basis, be sure to sign up to the CMA's Critical Friend¸ a LinkedIn newsletter published bi-weekly maintained by Steptoe's London Antitrust partner, Ronan Scanlan.
