Merger Review and HSR Clearance: A Comprehensive Guide

76 questions on merger review and HSR clearance, answered and cited by the UpLaw editorial team.

• Can a company fix its Item 4 documents after signing?
• Can a merger be challenged for harming workers rather than consumers?
• Can private parties challenge a merger?
• Does a roll-up have an antitrust problem if none of its deals are reportable?
• Does Chevron deference apply to the antitrust agencies?
• Does expiration of the HSR waiting period mean the merger is approved?
• Does it matter whether the FTC or the DOJ reviews a merger?
• Have efficiencies ever saved a merger in court?
• How can bad risk allocation kill an otherwise-fixable deal?
• How did General Dynamics change the analysis of market shares?
• How do Delaware courts treat regulatory-efforts covenants?
• How does a qualification requirement defeat an entry defense?
• How does the clock work after a Second Request?
• How does the EU merger regime differ from HSR?
• How have recent decisions weakened the FTC's administrative forum?
• How is a vertical merger analyzed for foreclosure?
• How is the HHI calculated and what thresholds apply?
• How is transaction value determined for HSR purposes?
• How long is the HSR waiting period?
• How should a divestiture cap be drafted?
• How significant is the 2023 tightening of the concentration screens?
• How strong must a rebuttal case be?
• Is early termination of the HSR waiting period available?
• Is the UK merger regime really voluntary?
• What are the 2023 Merger Guidelines and what force do they carry?
• What are the efforts standards for obtaining antitrust clearance?
• What are the elements of the failing-firm defense?
• What are the eleven guidelines in the 2023 Merger Guidelines?
• What are the most valuable hours in a Second Request?
• What are the penalties for failing to file an HSR notification?
• What are the potential-competition theories under Section 7?
• What are the recurring market-definition fights in merger cases?
• What are the recurring traps in merger practice?
• What are the ten things that decide a merger?
• What are the three tests for HSR reportability?
• What changed in the 2025 HSR form?
• What did Procter & Gamble say about merger efficiencies?
• What did the AT&T/Time Warner case establish about vertical theories?
• What does a proper clean-team protocol require?
• What does Clayton Act Section 7 prohibit?
• What does the Illumina/GRAIL matter teach about behavioral fixes?
• What evidence actually decides merger cases?
• What evidence proves a unilateral-effects case?
• What HSR exemptions matter in practice?
• What is a coordinated-effects theory?
• What is a pull-and-refile and when should you use it?
• What is a reverse termination fee in a merger agreement?
• What is a Second Request?
• What is a timing agreement in merger review?
• What is a unilateral-effects theory of harm?
• What is Guideline 8 and why does it matter for private equity?
• What is gun-jumping?
• What is Item 4 of the HSR form and why does it matter so much?
• What is permitted and prohibited during the interim period?
• What is the Baker Hughes burden-shifting framework?
• What is the coordination trap in multi-jurisdictional merger review?
• What is the FTC's Section 13(b) preliminary-injunction standard?
• What is the hypothetical monopolist test?
• What is the incipiency principle in merger law?
• What is the most common drafting failure in antitrust-sensitive deals?
• What is the structural presumption from Philadelphia National Bank?
• What is Tunney Act review?
• What must an efficiencies claim show to be cognizable?
• What other jurisdictions and regimes can delay a global deal?
• What parts of Brown Shoe remain good law?
• What state-law layer sits alongside federal merger review?
• When does an entry defense succeed?
• When does the "investment only" HSR exemption fail?
• Where should counsel start on a live deal?
• Who is the "person" for HSR purposes?
• Why do agencies prefer structural to behavioral remedies?
• Why do coordinated-effects cases fail?
• Why do divestitures fail, and how do agencies now structure them?
• Why is merger review different from the rest of antitrust law?
• Why is the preliminary-injunction stage effectively the whole merger case?
• Why was the Hart-Scott-Rodino Act enacted?