M&A Regulation & Disputes 2026

Approval Pathways and Courtroom Risks: Global M&A Regulation & Disputes

This cross-border guide provides a practical, jurisdiction-by-jurisdiction comparison of the laws, regulatory processes and disputes that shape modern M&A. It is designed for deal-makers and counsel who need to understand not only what the rules say, but how they are applied in live transactions and contested situations. Each chapter is written by leading advisers in the relevant jurisdiction and follows a structured format that allows readers to quickly locate reliable guidance on common issues and to compare approaches across markets.

M&A is now scrutinised through multiple, overlapping lenses. Traditional merger control remains central, but it increasingly sits alongside foreign direct investment (FDI) and national security screening, sector-specific change-of-control approvals, and a wider ecosystem of regulatory and private litigation risk. These regimes have become more expansive, with more procedural steps to be taken, even as they have become more important for the eventual outcome of a deal than ever. In many transactions, the legal “closing path” is no longer a single filing or a predictable timetable, but a co-ordinated programme of regulatory engagement across several authorities, often in multiple jurisdictions, and frequently under public and third-party pressure.

This guide responds to that reality. It maps the regulatory architecture that governs M&A approvals and the dispute landscape that follows when deals are challenged, delayed, conditioned or blocked. It is intended to be used at the points where practical decisions must be made: whether a transaction is notifiable, where it should be filed, how long review may take, what substantive concerns are likely to arise, which remedies are realistically negotiable, and how to allocate risk in the transaction documents. Just as importantly, it addresses what happens when those processes become contentious – whether between the parties; with regulators; or through court proceedings brought by shareholders, competitors or other stakeholders.

Why a comparative guide matters now

Cross-border M&A has always required a working knowledge of different legal systems. What has changed is the intensity of regulatory intervention and the degree to which politics, industrial policy and national security considerations can determine outcomes. Competition authorities are increasingly willing to investigate complex theories of harm, scrutinise data-driven or innovation-focused mergers, and pursue enforcement strategies that do not always track historic precedents. Meanwhile, national security screening has expanded far beyond traditional defence assets, capturing sensitive technology, critical infrastructure, energy, communications, healthcare supply chains, strategic real estate and access to valuable datasets.

At the same time, M&A litigation has become, in many markets, both more sophisticated and more frequent. Disputes now commonly arise over termination rights, material adverse change/effect clauses, satisfaction of regulatory conditions, the parties’ obligations to seek approvals, and the adequacy of remedies offered to regulators. In some jurisdictions, transactions also face an increased risk of challenges to process, governance and disclosure. This is particularly the case in deals for listed companies and in situations involving conflicts of interest, minority shareholder concerns or contested auctions.

The questions this guide is built to answer

The guide is structured around the questions that arise when planning and executing M&A in this – more heavily regulated and litigated –than ever environment. Contributors address, among other topics, the following.

• How the enforcement environment is changing – what has shifted in the past 12 months, where authorities are intervening more actively, and what trends are emerging in the theories of harm, sectors of focus and procedural approach.
• What laws and institutions matter most – the principal statutes, regulations and policy instruments; the responsible authorities; and how their mandates and powers are allocated.
• How far regimes reach – whether foreign-to-foreign transactions are caught, how “local effects” are assessed, and how extraterritorial enforcement risk is managed.
• How parallel regimes interact – sequencing, co-ordination, information-sharing, and how to manage inconsistent demands or timelines across regulators.

Regulatory strategy and early risk assessment

Effective regulatory planning begins before signing. Parties need to identify likely filing obligations, assess substantive exposure, and determine which authorities will be most influential. This includes understanding not only thresholds and formal jurisdiction, but also informal expectations, such as when voluntary filings are “strongly recommended”, and when pre-notification engagement is essential to keep a transaction on track.

Regulatory timetables can dictate deal viability. The guide provides practical insight into review phases and timelines and the information requirements that often expand during an investigation. It explains the purpose and practice of pre-notification, what authorities tend to focus on in early engagement, and how parties can reduce execution risk through coherent document strategy and internal preparedness.

Substantive analysis in merger control: theories of harm and remedies

Substantive analysis has become a vital part of merger control, particularly where transactions involve digital ecosystems, vertical integration, conglomerate effects, nascent competition or innovation. The guide covers the applicable substantive tests and how they are applied in practice, the theories of harm most commonly examined, and the evidentiary expectations around efficiencies and failing firm arguments.

National security screening, geopolitical sensitivity and sectoral approvals

The guide explains how FDI and national security regimes are structured, what triggers filings, when voluntary notifications are advisable, and how mitigation measures are imposed ranging from governance controls and information barriers to local data storage, operational restrictions or carve-outs of sensitive assets

In regulated sectors such as financial services, energy, telecoms, aviation and media, sectoral regulators can have decisive influence. The guide summarises the approval processes, typical timelines, the substantive standards applied (such as prudential soundness and fitness and propriety), and how sectoral reviews are co-ordinated with merger control and national security screening. It also flags practical pitfalls that repeatedly disrupt timelines, such as incomplete filings, insufficient stakeholder planning or overly rigid transaction documentation.

Disputes: from deal friction to courtroom outcomes

Even well-planned deals can become contentious. The guide therefore treats disputes as a core feature of modern M&A, not an afterthought.

It covers M&A litigation relating to substantive deal issues, including the frequency and types of disputes, challenges to governance and disclosure, broken-deal litigation, and disputes over termination rights and conditions. It analyses how courts and tribunals approach material adverse change/effect clauses, what standards are applied to efforts obligations, and how disputes over remedies or regulatory strategy are resolved. It also surveys the forums commonly used – courts, arbitration and specialist tribunals – and the availability of interim relief, specific performance, injunctions and damages.

Separate attention is given to litigation relating to regulatory decisions, including judicial challenges to prohibitions, conditional clearances and fines. The guide addresses standing (including third-party access), the standard of review and deference to regulators’ technical assessment, the availability of suspensive relief pending appeal, and how public law challenges interact with private damages actions.

Finally, the guide examines private enforcement and competition/regulatory claims connected to M&A conduct – such as gun-jumping, information exchange and alleged co-ordination – alongside collective actions, limitation issues, causation and quantification. It also considers settlement pathways, mediation and arbitration, recognising the growing role of ADR in high-stakes disputes.

Outlook and practical guidance

The concluding section of each Law and Practice chapter looks forward. Contributors outline expected legislative, policy and enforcement developments over the next 12–24 months and provide practical tips for planning transactions: how to build credible regulatory narratives, when to engage authorities, how to structure documentation to handle divergent outcomes, and how to anticipate cross-border and geopolitical complications (including sanctions and sensitive investor issues).

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This guide is intended to be both a reference and a working tool. It provides the key information needed to plan and execute transactions and offers a network of trusted experts across jurisdictions who understand the local realities behind the rules. We thank the contributors for their time, insight and practical judgment.