The UK’s Competition and Markets Authority has reduced its oversight of global mergers, moving away from its post-Brexit role as one of the most assertive antitrust regulators worldwide.
From interventionist outlier to a lighter touch
Between 2020 and 2022, the authority sent 30–40% of Phase 1 merger cases to deeper Phase 2 investigations, compared with 10–20% before 2018. Over half of those deals were either blocked or withdrawn. This approach set it apart, especially in cases with no direct UK connection, including several major US-to-US transactions.
The peak came when the CMA initially blocked Microsoft’s $69 billion purchase of Activision Blizzard in 2023. The European Commission had already approved the deal with conditions, and a US court declined to intervene. After political pressure and a judicial review, the agency later approved a revised version with restrictions.
By early 2025, its stance had changed. The number of Phase 1 cases fell to 32 in the year ending March 2026, the lowest in two decades. Only seven cases moved to a “case review meeting,” down from 20 the previous year and 32 the year before. The 2025 calendar year saw the fewest interventions since the current merger system began in 2003.
Government pressure and the “4Ps” overhaul
The shift followed criticism from businesses and the UK government, which claimed regulatory overreach was discouraging investment. In January 2025, the CMA’s chair was removed amid calls for regulators to prioritize economic growth.
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The agency had already started adjusting its methods in late 2024 with the “4Ps” initiative—emphasizing pace, proportionality, predictability, and process. Key changes included:
- Earlier discussions with merging parties, including a new “Mergers Charter” setting clear expectations.
- A 40-working-day goal for pre-notification steps, which the CMA has met since June 2025.
- A 25-working-day target for simple Phase 1 clearances, also achieved since mid-2025.
- More flexible remedies, such as behavioral fixes at Phase 1.
Legislative updates in early 2025 further limited the CMA’s discretion. Phase 2 decisions, once handled by an independent panel, now involve a group with a majority of agency executives. The reforms also tightened jurisdictional tests, including the “share of supply” threshold and the “material influence” standard for reviewable control.
The change hasn’t been consistent. While the CMA has eased its stance on some global deals, it remains active where UK consumers face direct effects. In Shutterstock/Getty Images, it narrowed its Phase 2 review to focus on UK editorial markets after accepting that generative AI was altering global competition. The deal collapsed when the CMA demanded divestment of Shutterstock’s editorial operations. In Aramark/Entier, the authority ordered the unwinding of a US company’s purchase of a UK offshore catering business but allowed Aramark to keep the Australian portion.
Informal reviews and the “wait-and-see” approach
The CMA’s Mergers Intelligence Committee, which tracks unnotified deals, has seen an increase in informal submissions. Companies can submit briefing papers explaining why a transaction doesn’t raise UK competition issues or lacks jurisdiction. These submissions rose to 217 in the year ending March 2026, up from 187 the prior year.
Some high-profile deals, like Mars/Kellanova and Google/Wiz, appear to have been cleared this way, avoiding formal review. The CMA has also adopted a “wait-and-see” stance for global transactions where remedies in other jurisdictions might address UK concerns. In 2025–26, it reported two such cases, one of which was cleared elsewhere while the other remained unresolved.
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In Subsea 7/Saipem, the CMA limited its review to the UK Continental Shelf, clearing the deal without conditions while leaving broader concerns to other regulators. Yet the agency hasn’t retreated completely. In Global Business Travel Group/CWT, a US-to-US deal, it initially raised significant concerns but later approved it unconditionally after two panel members changed their views. The US Department of Justice had sued to block the deal but later dropped its challenge.
Foreign-to-foreign mergers still make up about half of the CMA’s interventions—far above the pre-2018 rate of 25%. The new approach suggests a more focused strategy, though its willingness to step in where UK markets are affected remains unchanged.
Companies now consider several factors when deciding whether to engage with the authority. They assess whether the deal has a direct and distinct impact on UK consumers. If not, parties can submit a briefing paper to the MIC explaining why. Other considerations include:
- Whether the case is straightforward or involves complex theories of harm. Detailed economic analysis may still require a full notification.
- The deal’s timeline and how a CMA review would interact with other jurisdictions. If remedies in the US or EU could resolve UK concerns, a “wait-and-see” approach may work.
- Whether closing can be made conditional on the CMA’s response. Some agreements include “springing” conditions requiring agency consent only if it calls in the deal before completion.
The CMA’s current stance balances reducing regulatory friction for global deals with maintaining oversight where UK markets are involved. For now, it continues to enforce this distinction.
Businesses handling these changes may find guidance on adapting to regulatory shifts in career development strategies for legal professionals.