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Integrity Path
Category: Antitrust and Competition

Merger Review

Also known as: Merger Control, Merger Clearance
Simply put

Merger review is the process by which government competition authorities examine a proposed merger or acquisition to determine whether it is likely to reduce competition, for example by leading to higher prices or lower quality. In the United States, this review is conducted by agencies such as the Federal Trade Commission's Bureau of Competition and the Department of Justice Antitrust Division. Companies planning certain deals must typically wait a defined period before closing while authorities conduct a preliminary review.

Formal definition

Merger review is the regulatory process through which competition (antitrust) authorities assess proposed mergers and acquisitions to prevent transactions likely to substantially lessen competition. In the U.S., it is administered by the FTC's Bureau of Competition and the DOJ Antitrust Division, and includes a statutory waiting period during which parties must delay closing, 30 days for most transactions and 15 days for cash tender offers or bankruptcy transactions, pending preliminary review. Analytical elements include market definition and, under evolving merger guidelines, an increased focus on competitive effects. Internationally, the OECD Recommendation on Merger Review (adopted by the OECD Council on 23 March 2005) provides non-binding guidance on merger review procedures. This term refers specifically to antitrust/competition clearance and is distinct from internal compliance or ethics due-diligence of a target company, which is not encompassed by 'merger review' as used by competition authorities. This entry is educational and jurisdiction-specific; procedures and thresholds vary by jurisdiction and require confirmation against primary sources and qualified legal counsel.

Why it matters

Merger review is the gatekeeping mechanism that determines whether a proposed transaction can lawfully close. Because competition authorities such as the FTC's Bureau of Competition and the DOJ Antitrust Division are focused on preventing mergers and acquisitions that are likely to reduce competition, for example by leading to higher prices or lower quality, a deal that proceeds without satisfying applicable review requirements can face serious legal jeopardy, including challenges to the transaction itself. For companies contemplating M&A activity, understanding when review is triggered and what the process entails is essential to deal planning and timing.

The statutory waiting period is a defining feature: in the U.S., parties must typically wait 30 days (15 days in the case of a cash tender offer or bankruptcy transaction) before closing while authorities conduct a preliminary review. This built-in delay affects deal timelines, financing arrangements, and closing commitments, and failure to observe the waiting period can carry consequences. Merger review is jurisdiction-specific, and thresholds and procedures vary; transactions with international dimensions may face review under multiple regimes, and the OECD Recommendation on Merger Review (adopted by the OECD Council on 23 March 2005) offers non-binding guidance on procedures across jurisdictions.

It is important to distinguish merger review, as used by competition authorities, from the internal compliance or ethics due-diligence a company may perform on a target. Merger review refers specifically to antitrust/competition clearance and does not encompass an acquirer's internal integrity assessment of a target's compliance program, culture, or past conduct. Conflating the two can lead teams to assume that clearing antitrust review addresses compliance risk, or that internal due-diligence satisfies regulatory clearance obligations, neither of which is accurate. This entry is educational and not a substitute for advice from qualified legal counsel.

Who it's relevant to

Legal and Antitrust Counsel
In-house and outside counsel responsible for M&A transactions must determine whether a deal triggers merger review, manage the applicable waiting period, and respond to competition authorities. Because procedures and thresholds vary by jurisdiction and require confirmation against primary sources, this function is central to lawful deal execution.
Corporate Development and M&A Teams
Teams structuring and timing transactions need to account for the statutory waiting period, generally 30 days, or 15 days for cash tender offers or bankruptcy transactions, and for the possibility of extended review. Merger review timing directly affects deal schedules, financing, and closing commitments.
Compliance and Ethics Program Managers
While merger review is an antitrust/competition clearance process and is distinct from internal compliance or ethics due-diligence of a target, compliance professionals should understand the boundary between the two. Clearing antitrust review does not address integrity risks in a target, and internal due-diligence does not satisfy regulatory clearance obligations; each should be managed as a separate activity.
Executive Leadership and Boards
Leaders approving transactions benefit from understanding that merger review can constrain deal timing and, in some cases, the viability of a transaction whose competitive effects are a concern to authorities. Realistic expectations about the review process support sound deal governance.

Inside Merger Review

Antitrust/Competition Clearance
Merger review is the process by which a competition authority examines a proposed merger, acquisition, or combination to assess whether it may substantially lessen competition or create a dominant market position. It is a legal/regulatory process, not a compliance-training concept, and its specifics vary by jurisdiction.
Notification and Filing Requirements
Many jurisdictions require parties to notify the relevant competition authority before closing a transaction that meets defined thresholds (for example, based on turnover or asset value). Applicable thresholds, forms, and timing are jurisdiction-specific and should be confirmed against the governing statute and the authority's published guidance.
Substantive Competitive Assessment
The reviewing authority analyzes the transaction's likely effect on competition, which may include market definition, market share and concentration, potential for coordinated or unilateral effects, and possible efficiencies. The exact analytical framework depends on the jurisdiction and the authority's methodology.
Remedies and Conditions
Where competitive concerns are identified, an authority may clear a transaction subject to conditions, such as structural remedies (e.g., divestitures) or behavioral commitments. Availability and form of remedies are governed by the applicable competition regime.
Outcome (Clearance, Conditional Clearance, or Prohibition)
A review may conclude with unconditional clearance, conditional clearance, or a decision to block the transaction. Outcomes depend on the facts, the applicable law, and the authority's discretion, and vary across jurisdictions.

Common questions

Answers to the questions practitioners most commonly ask about Merger Review.

Does 'merger review' mean the internal compliance and ethics due diligence a company performs on an acquisition target?
No. Merger review refers to the examination of a proposed merger or acquisition by a competition or antitrust authority to assess its effect on competition in relevant markets. It is a regulatory clearance process, not an internal integrity or compliance assessment of a target company. The internal review of a target's compliance culture, past misconduct, or ethics risks is a separate activity commonly called compliance due diligence, and it should not be conflated with merger review. This distinction matters because the two activities involve different actors, objectives, and legal frameworks.
Is merger review the same as antitrust clearance, or are they different processes?
Merger review is the antitrust or competition-law clearance process; the terms describe substantially the same activity. A competition authority reviews a transaction to determine whether it may substantially lessen competition or create market dominance, and clearance is the outcome when the authority permits the transaction to proceed, sometimes subject to conditions. Merger review is not a distinct compliance-program function separate from antitrust analysis. Specific thresholds, notification requirements, and review timelines are jurisdiction-specific and should be confirmed against the applicable competition authority's rules.
Which authority conducts merger review, and does it depend on where the company operates?
The reviewing authority is jurisdiction-specific. Different jurisdictions assign merger review to their designated competition or antitrust regulators, and a single transaction may be subject to review in more than one jurisdiction if it meets the applicable notification thresholds in each. Because obligations, filing thresholds, and processes vary by jurisdiction and can change, companies should identify all jurisdictions where filing may be required and confirm current requirements with qualified antitrust counsel. This entry is educational and not a substitute for legal advice.
When in a transaction should merger review considerations be addressed?
Merger review considerations are generally addressed early in transaction planning, because notification obligations and potential timelines can affect deal structure, closing conditions, and the schedule. Parties often assess whether applicable thresholds are met before committing to a transaction, since a required filing may prevent closing until clearance is obtained. Exact triggers, waiting periods, and effective dates are jurisdiction-specific and should be confirmed against primary regulatory sources and with qualified counsel.
What role does a compliance or ethics function play in relation to merger review?
Merger review itself is an antitrust matter typically led by legal and, where applicable, external antitrust counsel rather than by the compliance or ethics function. A compliance function's related contribution is generally distinct: it may support competition-law compliance training, help ensure that pre-closing conduct between the parties respects applicable rules on information exchange and coordination, and reinforce policies on lawful competitive behavior. These supporting activities are intended to reduce competition-law risk but do not constitute the merger review process, which remains a regulatory determination.
What are common pitfalls when accounting for merger review in transaction planning?
A frequently cited pitfall is failing to identify all jurisdictions where a filing may be required, which can delay closing or expose parties to enforcement risk. Another is underestimating the time a review may take, which can affect scheduling and financing arrangements. Parties should also be attentive to rules governing conduct between signing and clearance, since inappropriate coordination or premature integration can raise competition-law concerns. Because these matters vary by jurisdiction and depend heavily on the facts, they require analysis by qualified antitrust counsel; this entry does not provide legal advice.

Common misconceptions

Merger review means conducting compliance and ethics due diligence on a target company's integrity program.
Merger review is an antitrust/competition-law process administered by a competition authority to assess a transaction's effect on competition. Assessing a target's compliance program, code of conduct, or ethics posture is a separate due-diligence activity and is not what 'merger review' refers to. These distinct activities should not be conflated.
Merger review requirements are the same everywhere, so one filing satisfies all jurisdictions.
Notification thresholds, procedures, timing, and substantive standards are jurisdiction-specific. A transaction may be reviewable in multiple jurisdictions or in none, depending on where the relevant thresholds are met. Requirements must be confirmed against the primary sources for each applicable regime.
Merger review is a matter that compliance training staff can resolve internally without legal input.
Merger review involves binding legal obligations, filing deadlines, and potential penalties for failure to notify or for premature closing (gun-jumping). It requires qualified antitrust/competition counsel. Glossary entries are educational and are not a substitute for professional legal advice.

Best practices

Engage qualified antitrust/competition counsel early to determine whether a transaction is reviewable in each relevant jurisdiction, as thresholds and procedures vary by regime and should be confirmed against primary sources.
Do not conflate antitrust merger review with a target's compliance and ethics due diligence; treat them as separate workstreams with distinct owners, objectives, and expertise.
Confirm applicable notification thresholds, filing forms, and timing against each jurisdiction's governing statute and the competition authority's published guidance rather than relying on general assumptions.
Observe standstill obligations and avoid gun-jumping by refraining from closing or integrating operations before required clearances are obtained, subject to counsel's advice.
Coordinate multi-jurisdictional filings so that timelines, information requests, and any proposed remedies are managed consistently across authorities.
Document the analysis supporting notification decisions and preserve the involvement of legal counsel, recognizing that outcomes depend on the facts, applicable law, and authority discretion.