Merger Control 2026

As M&A Shows Signs of Recovery, Merger Control Recalibrates

As in recent years, the number of M&A transactions worldwide in 2025 remained well below the peak levels seen in 2021. However, there were indications of a recovery, at least in certain sectors and regions. Deal value increased meaningfully in the second half of 2025, driven in large part by transactions in the technology, media and telecommunications, energy and infrastructure sectors. US megadeals – including Union Pacific’s USD85 billion acquisition of Norfolk Southern and Kimberly-Clark’s nearly USD50 billion purchase of Kenvue, both currently undergoing regulatory review – led the way, while increases in deal value in other geographies, including Europe and Asia, were comparatively modest.

Overall, the long-anticipated resurgence in worldwide M&A activity has remained uneven at best, shaped by persistent geopolitical tensions, cautious capital deployment and a still-fragile macroeconomic outlook. Yet, in the absence of a full-scale global rebound in dealmaking, merger control regimes around the world have continued to evolve at pace.

What is emerging is not a simple tightening or loosening of merger control enforcement, but a broader recalibration of policy. Authorities are reassessing how merger control should operate in a world increasingly defined by industrial policy, supply chain resilience, technological rivalry and sustainability considerations. For merging parties, this means that the challenge is no longer just navigating complex rules but understanding how these rules are being interpreted in real time. And, most importantly, how this recalibration of merger control, still very much a work-in-progress, is likely to impact their deal, if at all.

Against this backdrop, 2026 is shaping up to be a year in which the direction of travel may in some respects become clearer, even if the ultimate destination does not.

Changing landscapes across key merger control jurisdictions

European Union

In the EU, the long-anticipated review of the European Commission’s merger control guidelines has moved from policy debate to concrete proposal. On 30 April 2026, the Commission launched a public consultation on draft new EU Merger Guidelines, intended to replace both the 2004 Horizontal Merger Guidelines and the 2008 Non-Horizontal Merger Guidelines.

The new draft reflects a discussion that began in earnest following the Commission’s 2019 prohibition of Siemens’ proposed acquisition of Alstom and grew louder following the 2024 Draghi Report, which described the need to increase European productivity as “an existential crisis”. Namely, how EU merger control can allow European companies to reach the scale needed to compete globally with – in particular – US and Chinese rivals, without compromising the Commission’s core commitment to preserving effective competition within the EU. Unsurprisingly, the draft guidelines give greater visibility to themes such as innovation, resilience and sustainability. They also suggest a willingness of the Commission to look beyond short-term price effects in favour of longer-term procompetitive outcomes. What practical effect this “new” approach will have on the Commission’s assessment of mergers remains to be seen. Until there is clear evidence of a shift in practice, however, merging parties should not assume that the Commission will become significantly more permissive.

Although the draft guidelines have understandably attracted much of the recent attention, another development – the proliferation of “call-in” powers – may ultimately prove more consequential for merging parties. These powers allow member state competition authorities to assert jurisdiction over transactions that fall below their filing thresholds and, in some cases, refer such transactions to the Commission for review. While the objective is to prevent potentially problematic deals from escaping European scrutiny, the expansion of these powers has significantly reduced the legal certainty that filing thresholds once provided, making it increasingly difficult for parties to conclude with confidence that a transaction will not be reviewed in Europe.

United States

US merger control is in transition. There is a markedly different tone at the federal agencies than there was under the Biden administration, when Lina Khan chaired the Federal Trade Commission (FTC) and Jonathan Kanter led the Antitrust Division of the Department of Justice (DOJ). Their replacements, Andrew Ferguson at the FTC and Gail Slater at DOJ (recently departed), have signalled a greater willingness to operate within more traditional enforcement frameworks, placing greater emphasis on established principles, rather than aggressively expanding the boundaries of merger control law. Among other things, there is now more openness at the agencies to remedies as a means of resolving competition concerns, allowing a path for otherwise problematic mergers to proceed. This likely has also resulted in fewer deals dying in the boardroom based on the regulatory hurdles being viewed as insurmountable.

An important procedural development is that the new, more burdensome Hart-Scott-Rodino (HSR) form introduced in February 2025 has, at least for now, been set aside following legal challenges. As a result, filings are currently being accepted using the pre-February 2025 form, which is substantially less onerous. This should lead to a shorter overall timeline for US approval, especially in straightforward cases, as less time is needed to complete the HSR form.

This is certainly not to suggest that the road to US merger control approval is without obstacles. US enforcement remains robust, particularly in politically sensitive or strategically important sectors. This is not surprising, as the first Trump administration was not known to be soft on mergers. At the same time, political and policy considerations are widely perceived to play an increasingly important role in the review of certain high-profile transactions, placing a premium on advisers with strong government experience, institutional credibility and access.

Adding to the complexity, state attorneys general are playing an increasingly prominent role in merger control enforcement in the US, including through state-level notification requirements. A prime example of this is the review of Paramount’s proposed USD110 billion acquisition of Warner Bros. in California, where the attorney general has “committed to fighting market consolidation that we find unlawful”, independently from whatever decision the DOJ may take regarding the deal.

United Kingdom

The Competition and Markets Authority (CMA) is in the process of recalibrating its merger control enforcement around the themes of pace, predictability, proportionality and process, with the aim of maintaining effective enforcement while at the same time ensuring business confidence.

As part of a wider package of potential refinements to the UK competition law regime proposed by the UK government (which is the subject of an ongoing consultation process), it has been proposed to limit the criteria that the CMA may apply when assessing whether an acquirer has the ability to exert “material influence” over a target’s commercial policy and conduct on the market, as well as to provide exhaustive (rather than merely illustrative) criteria for the “share-of-supply” test to be met.

The CMA has also recently revised its merger remedies guidance, indicating a greater willingness under certain circumstances to accept behavioural (as opposed to structural) remedies as resolving competition concerns arising from a merger. This openness to behavioural remedies has, to some degree, already started to be reflected in the CMA’s practice.

Notwithstanding the outcome of the current consultation, the UK will remain a critical merger control jurisdiction. Although its regime is formally “voluntary” and will remain so, the CMA has proven to be a force to be reckoned with. Merging parties that overlook the UK as a merger control jurisdiction do so at their peril, especially in the case of deals with a clear UK nexus.

Other jurisdictions

These are only a few of the jurisdictions that companies must bear in mind when seeking regulatory approval of their mergers. It is also not unusual for global deals to require merger control notification and approval in countries such as Australia, Brazil, Canada, China, Japan, South Korea and Turkey, to name just a few. Some of these countries are undergoing their own recalibrations in response to the current geopolitical climate and industrial policy objectives.

At the same time, the boundaries between merger control and other regulatory frameworks are becoming increasingly blurred. Foreign direct investment screening – and, in the EU, foreign subsidies screening in merger cases – now play a central role in transaction planning. While distinct in legal basis, these regimes often operate in parallel, adding layers of complexity and co-ordination challenges.

Despite commitments of authorities in various jurisdictions to lower burdens on companies in order to encourage investment and stimulate economic growth, in-house and external counsel seeking quick and efficient deal approval face a more complicated landscape than ever before. This makes having a clear guide such as this one all the more essential. Indeed, the Chambers Merger Control 2026 guide provides answers to all the most pressing questions companies and their lawyers face with every notifiable transaction.

Where to file

For starters, where does the deal need to be filed for approval? This is a crucial question, as there are potentially serious consequences for failing to make a required merger control filing, including the imposition of heavy fines. Unfortunately, it can be tricky to determine where filings are required in a given case.

Although an ever-increasing number of countries have some form of merger control law, there remains very little standardisation, with each merger control regime continuing to have its own test to determine which transactions amount to a notifiable event. Some jurisdictions catch only changes in control, while others also cover certain acquisitions of non-controlling minority stakes.

Moreover, every jurisdiction has its own set of filing thresholds based on various factors, such as the parties’ revenues, asset value, market share, and the size of the transaction. An increasing number of authorities now also have “call-in” powers. Given this, determining where to file requires a careful country-by-country analysis. As such, each chapter of the 2026 edition of the Chambers Merger Control guide indicates whether that jurisdiction has such powers and whether it has in fact called in below-threshold transactions.

Many countries (virtually every EU member state, as well as dozens of non-EU countries) now have foreign direct investment (FDI) legislation that may require additional filings and approvals. Merging parties also face the possibility of having to make a separate, potentially very onerous filing under the EU Foreign Subsidies Regulation (FSR). The FSR requires, inter alia, notification to and prior approval by the European Commission of certain transactions where one party is established in the EU and the other (typically the acquirer, but also possibly a merging party or joint venture partner) benefits from “financial contributions” meeting certain monetary thresholds. Although neither FDI nor foreign subsidies approval fall within what one traditionally has in mind when speaking of “merger control”, they represent significant additional hurdles increasingly faced by merging companies that should be considered at early stages of deal planning and may delay when closing can occur.

Substantive reviews

Once it has been determined where merger control filings need to be made, the next question is what the regulatory reviews will entail and what needs to be done in order to obtain approval in each jurisdiction. Again, each merger control regime has its own test for determining whether a given transaction will be approved – while the approach may be broadly similar across jurisdictions, there are nuances in each that are important to understand.

For example, is the legal test for assessing mergers based on maintaining effective competition, avoiding the creation or strengthening of a dominant position, or some other standard? Are vertical mergers subject to the same level of scrutiny as horizontal mergers? How are efficiencies considered by the regulator in its assessment? Is the agency’s analysis based purely on competition law principles or are there other (eg, public interest) considerations at play? What kinds of arguments are most likely to be persuasive to each authority, and how does one ensure a consistent approach across jurisdictions given international co-operation between regulators?

Timing

Of course, another key issue will be how the regulatory process affects timing. After all, there is no such thing as a deal that is not time-sensitive. In every transaction, there is a sense of urgency and a desire to close as soon as possible, ideally the day before yesterday.

This urgency needs to be reconciled with the fact that, with some notable exceptions, most merger control jurisdictions require closing to be suspended until regulatory approval has been granted. Taking into account the time needed to prepare the filing(s), which in challenging cases can easily be hundreds of pages long (excluding annexes) in certain jurisdictions, the time spent in “pre-notification consultations” with the relevant authorities before formal filing occurs, and the time it takes for the review process(es) to play out, closing can easily be delayed for a couple of months in simple cases, or for well over a year in more challenging ones.

Reasonable timelines need to be set for the parties, and expectations must be managed carefully. Once again, every jurisdiction has its own procedural rules and deadlines, so co-ordinating the reviews across the world can be a significant challenge. This applies even more so where remedies are required in order to obtain approval in one or more jurisdictions.

Conclusion

For the above reasons (and many more), navigating a global merger control filing and approval process is a complex business, and it is getting more complex every year. The Chambers Merger Control 2026 guide aims to cut through some of that complexity by providing the reader with a practical guide, in a user-friendly format, that covers many of the world’s leading merger control jurisdictions.

The sections in this guide cover the key rules relevant for a merger control filing assessment, including:

• the kinds of transactions that have to be notified (or are subject to review);
• what the filing thresholds are;
• the procedure and timeline for notification and approval;
• the substantive considerations of the authorities; and
• what kind of enforcement record the authorities have.

However, the chapters also go beyond the letter of the law and provide useful information on how these rules are applied in practice. For instance, the sections on applicable fines for failure to file cover not only whether such penalties exist and what their legal maximum is, but, more importantly, whether these penalties are applied in practice and what penalties have been imposed recently.

Although by no means a substitute for seeking advice from experienced merger control counsel, this guide provides clear and practical answers to most of the fundamental questions faced by any company involved in a transaction that requires merger control filings (while also addressing foreign direct investment and foreign subsidies filings and approvals). The reader will find this guide to be a very useful tool for navigating their way through the increasingly complex labyrinth of global merger control.

As always, this work is the result of a collective effort. We extend our sincere thanks to all the authors for their contributions and to the Chambers team for their continued diligence and professionalism.