M&A

Antitrust review

Assess how the transaction may affect competition, prepare the supporting evidence and integrate agency review into the deal timetable and risk allocation.

Quick answer

Antitrust review is the competition-law assessment of whether a proposed transaction may substantially lessen competition or create other prohibited effects under the applicable law. Review can include notification, an initial waiting period, information requests, economic analysis, remedies, clearance or challenge.

Use the worked example

Meaning and transaction use

The DOJ and FTC Merger Guidelines describe frameworks and tools the agencies use to assess whether mergers may violate United States antitrust law. [S1]

The guidelines state that the agencies examine the totality of available evidence and may apply several analytical frameworks depending on the transaction. [S1]

The DOJ explains that a second request can extend review and seek further information and documents when an HSR review requires deeper investigation. [S2]

Worked example

Illustrative data-readiness tracker only. Assume 24 requested market, customer, pricing and strategy data sets: 18 validated, 4 submitted for validation and 2 missing.

Scroll the table horizontally to view all columns.

MeasureCalculationResult
Validated18 / 2475.0%
Under validation4 / 2416.7%
Missing2 / 248.3%
Received(18 + 4) / 2491.7%

Twenty-two data sets have been received and two remain missing. The percentages do not indicate the likely antitrust outcome.

Proposed transaction review process

Screen the transaction

Identify overlaps, vertical links, potential entry issues, data needs and filing regimes.

Develop the evidence

Validate sales, customer, product, pricing, capacity, strategy and market records.

Manage agency review

Coordinate filings, questions, custodians, productions, economic work and timetable commitments.

Evaluate outcomes

Assess clearance, remedy, litigation and termination scenarios with value and timing effects.

Evidence checklist

Market evidence

Products, services, geographies, customers, competitors, entry and substitution records.

Commercial evidence

Pricing, bids, win-loss, margins, capacity, innovation and strategy documents.

Transaction evidence

Rationale, board materials, synergy work, valuation and integration plans.

Review evidence

Filings, agency questions, production logs, economic analyses, commitments and decisions.

Decision framework

SituationProposed action
Data sources disagreeReconcile definitions, periods and entity scope before using the analysis.
Potential concerns appear materialTest evidence, remedies and timing effects with competition counsel and economists.
A second request is issuedActivate the production plan, governance, privilege controls and revised timetable.
A remedy affects deal valueModel the divestment or behavioural obligation and apply the agreement's risk allocation.

Common errors to check

  • Defining markets from internal labels without testing customer substitution.
  • Using inconsistent sales or geography definitions.
  • Ignoring ordinary-course documents that conflict with the deal narrative.
  • Treating notification acceptance as clearance.

Prepare the competition evidence room

Bring the overlap screen, data dictionary, transaction rationale and filing timetable to an antitrust-readiness review. Reconcile evidence gaps and identify execution risks for specialist counsel.

Discuss the transaction

Primary references and editorial scope

  1. DOJ and FTC: 2023 Merger Guidelines
    United States agency frameworks, evidence and tools used in merger review. Reference checked 17 September 2026.
  2. DOJ: Merger Review Process Initiative background
    Example second-request process, additional information and document review. Reference checked 17 September 2026.
Editorial qualification

General transaction education using United States federal materials. Figures are hypothetical. Competition-law standards, filing obligations, thresholds, evidence and procedure differ by jurisdiction and require specialist advice.

General business information. Obtain advice appropriate to the legal, tax, accounting and financing facts. No offer, lender commitment or transaction outcome is represented. All worked examples use expressly assumed figures. Editorial draft date: 17 September 2026.

WhatsApp