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Merger Guidelines

The Antitrust Division of the U.S. Department of Justice and the Federal Trade Commission recently released the 2023 Draft Merger Guidelines on July 19 and called for public comments. Those comments were due on September 18, and more than 1500 public comments are hosted on the agencies’ site.

This page, maintained by the Thurman Arnold Project at Yale, contains a small set of curated comments drawn from those public submissions as well as links to other high-quality articles commenting on the draft merger guidelines. We have focused on comments from economists with research and policy experience, especially those that highlight relevant research findings. This selection of substantive and constructive comments will help agency staff and leaders reform the Guidelines to achieve more effective protection of competition and consumers.

The commenters are listed in alphabetical order, and each name is followed by the file of their comments as well as any supporting literature that was attached to the comment. The list below will continue to be curated and expanded by the TAP team.

Selected Comments and Articles

Jonathan Baker et al.

David W. Berger et al.

Stephen Calkins

Cory S. Capps and Leemore Dafny
ProMarket Article 1 | ProMarket Article 2

Joseph Farrell
Comment 1 | Comment 2 (with Jonathan Baker)

Eleanor Fox
Comment | ProMarket Article 1 | ProMarket Article 2

Herbert Hovenkamp
Abstract | Comment | ProMarket Article 1 | ProMarket Article 2

Fiona Scott Morton
Comment | ProMarket Article

Eric Posner
Comment (with Berger et al.)| ProMarket Article 1 | ProMarket Article 2

Progressive Policy Institute

Steven C. Salop
Comment | Supplement | ProMarket Article 1 (with Jennifer Sturiale) | ProMarket Article 2

Carl Shapiro
Comment | ProMarket Article 1 | ProMarket Article 2

Lawrence J. White

Economics Literature Supporting the Revised Merger Guidelines

Guideline 1: Mergers Should Not Significantly Increase Concentration in Highly Concentrated Markets
Orley Ashenfelter, Daniel Hosken & Matthew Weinberg, The Price Effects of a Large Merger of Manufacturers: A Case Study of Maytag-Whirlpool, 5 AM. ECON. J.: ECON. POL’Y 239 (2013).
Herbert Hovenkamp & Carl Shapiro, Horizontal Mergers, Market Structure, and Burdens of Proof, 127 YALE L.J. 1742 (2018).
John Kwoka, The Structural Presumption and the Safe Harbor in Merger Review: False Positives or Unwarranted Concerns? 81 ANTITRUST L.J. 837 (2017).
Orley C. Ashenfelter, Daniel S. Hosken & Matthew C. Weinberg, Efficiencies Brewed: Pricing and Consolidation in the US Beer Industry, 46 RAND J. ECON. 328 (2015).
Ying Fan & Chenyu Yang, Competition, Product Proliferation, and Welfare: A Study of the US Smartphone Market, 12 AM. ECON. J.: MICROECONOMICS 99 (2020).
Ying Fan & Chenyu Yang, Estimating Discrete Games with Many Firms and Many Decisions: An Application to Merger and Product Variety (Nat’l Bureau of Econ. Research, Working Paper No. 30146, 2022)
Alice A. Bonaime & Ye Wang, Mergers, Product Prices, and Innovation: Evidence from the Pharmaceutical Industry, J. FIN. (forthcoming 2023),
Daniel S. Hosken, Luke M. Olson & Loren K. Smith, Do Retail Mergers Affect Competition? Evidence From Grocery Retailing, 27 J. ECON. & MGMT. 3 (2018).
Zack Cooper et al., The Price Ain’t Right? Hospital Prices and Health Spending on the Privately Insured, 134 Q. J. ECON. 51 (2019).
Thomas G. Wollmann, Stealth Consolidation: Evidence from an Amendment to the Hart-Scott-Rodino Act, 1 AM. ECON. REV.: INSIGHTS 77 (2019).
Zack Cooper et al., Do Higher-Priced Hospitals Deliver Higher-Quality Care? (Nat'l Bureau of Econ. Research, Working Paper No. 29809, 2023).
Guideline 2: Mergers Should Not Eliminate Substantial Competition Between Firms
Joseph Farrell & Carl Shapiro, Dynamic Competition with Switching Costs, 19 RAND J. ECON. 123 (1988).
Jean-Pierre Dubé, Günter J. Hitsch & Peter E. Rossi, Do Switching Costs Make Markets Less Competitive?, 46 J. MARKETING RES. 435 (2009)
Alexander MacKay & Marc Remer, Consumer Inertia and Market Power (2022),
Luís Cabral, Dynamic Price Competition with Network Effects, 78 REV. ECON. STUD. 83 (2011)
Dale O. Stahl II, Oligopolistic Pricing with Sequential Consumer Search, 79 AM. ECON. REV. 700 (1989).
Justus Haucap & Joel Stiebale, How Mergers Affect Innovation: Theory and Evidence, 63 INT'L J. INDUS. ORG. 283 (2019).
David E. Davis, Prices, Promotions, and Supermarket Mergers, 8 J. AGRIC. & FOOD INDUS. ORG. 1 (2010).
Thomas G. Wollmann, How to Get Away with Merger: Stealth Consolidation and its Effects on US Healthcare (Nat'l Bureau of Econ. Research, Working Paper No. 27274, 2021).
Peter Caradonna, Nathan H. Miller & Gloria Sheu, Mergers, Entry, and Consumer Welfare (Georgetown Univ. McDonough Sch. of Bus., Research Paper No. 3537135, 2023).
Vivek Bhattacharya, Gastón Illanes & David Stillerman, Merger Effects and Antitrust Enforcement: Evidence from US Retail (Nat'l Bureau of Econ. Research, Working Paper No. 31123, 2023).
Guideline 3: Mergers Should Not Increase the Risk of Coordination
Gaurab Aryal, Federico Ciliberto, and Benjamin T. Leyden, Coordinated Capacity Reductions and Public Communication in the Airline Industry, 89 REV. ECON. STUD. 3055 (2022).
Volker Nocke & Lucy White, Do Vertical Mergers Facilitate Upstream Collusion?, 97 AM. ECON. REV. 1321 (2007).
Ryan Mansley et al., A Price Leadership Model for Merger Analysis, 89 INT'L J. INDUS. ORG. (2023)
Nathan H. Miller, Gloria Scheu & Matthew C. Weinberg, Oligopolistic Price Leadership and Mergers: The United States Beer Industry, 111 AM. ECON. REV. 3123 (2021).
Giulio Federico, Gregor Langus & Tommaso Valletti, Reprint of: Horizontal Mergers and Product Innovation, 61 INT'L J. INDUS. ORG. 590 (2018).
Justus Haucap, Alexander Rasch & Joel Stiebale, How Mergers Affect Innovation: Theory and Evidence, 63 INT’L J. INDUS. ORG. 283 (2019).
Mitsuru Igami & Takuo Sugaya, Measuring the Incentive to Collude: The Vitamin Cartels, 1990–99, 89 REV. ECON. STUD. 1460 (2022).
Nathan H. Miller & Matthew C. Weinberg, Understanding the Price Effects of the MillerCoors Joint Venture, 85 ECONOMETRICA 1763 (2017).
Paul Grieco, Joris Pinkse & Margaret Slade, Brewed in North America: Mergers, Marginal Costs, and Efficiency, 59 INT’L J. INDUS. ORG. 24 (2018).
Guideline 4: Mergers Should Not Eliminate a Potential Entrant in a Concentrated Market
Colleen Cunningham, Florian Ederer & Song Ma, Killer Acquisitions, 129 J. POL. ECON. 649 (2021).
Guideline 6: Vertical Mergers Should Not Create Market Structures that Foreclose Competition
Volker Nocke & Lucy White, Do Vertical Mergers Facilitate Upstream Collusion? 97 AM. ECON. REV. 1321 (2007).
Gregory S. Crawford et al., The Welfare Effects of Vertical Integration in Multichannel Television Markets, 86 ECONOMETRICA 891 (2018).
John Asker, Diagnosing Foreclosure Due to Exclusive Dealing, 64 J. INDUS. ECON. 375 (2016).
Tasneem Chipty, Vertical Integration, Market Foreclosure, and Consumer Welfare in the Cable Television Industry, 91 AM. ECON. REV. 428 (2001).
Ali Hortaçsu & Chad Syverson, Cementing Relationships: Vertical Integration, Foreclosure, Productivity and Prices, 115 J. POL. ECON. 250 (2007).
Steven C. Salop, Invigorating Vertical Merger Enforcement, 127 YALE L.J. 1 (2018).
Serge Moresi & Steven C. Salop, When Vertical is Horizontal: How Vertical Mergers Lead to Increases in "Effective Concentration", 59 REV. INDUS. ORGS. 177 (2021)
Marissa Beck & Fiona Scott Morton, Evaluating the Evidence on Vertical Mergers, 59 REV. INDUS. ORG. 273 (2021).
Jean-Francois Houde, Spatial Differentiation and Vertical Mergers in Retail Markets for Gasoline, 102 AM. ECON. REV. 2147 (2012)
Fernando Luco & Guillermo Marshall, The Competitive Impact of Vertical Integration by Multiproduct Firms, 110 AM. ECON. REV. 2041 (2020).
Justine Hastings, Vertical Relationships and Competition in Retail Gasoline Markets: Empirical Evidence from Contract Changes in Southern California, 94 AM. ECON. REV. 317 (2004).
Fiona Scott Morton & Carl Shapiro, Strategic Patent Acquisitions, 79 ANTITRUST L.J. 463 (2013).
Guideline 7: Mergers Should Not Entrench or Extend a Dominant Position
Patricia M. Danzon & Michael A. Carrier, The Neglected Concern of Firm Size in Pharmaceutical Mergers, 84 ANTITRUST L.J. 487 (2022).
Patricia M. Danzon, Firm Size and Pharmaceutical Mergers: A Cross-National, Cross-Sector Perspective, 3 CONCURRENCES (2021).
Susan Athey & Fiona Scott Morton, Platform Annexation, 84 ANTITRUST L.J. 677 (2022).
Guideline 12: When an Acquisition Involves Partial Ownership... the Agencies Examine Its Impact on Competition
Miguel Antón et al., Common Ownership, Competition, and Top Management Incentives, 131 J. POL. ECON. 1294 (2023).
José Aazar, Martin C. Schmalz & Isabel Tecu, Anticompetitive Effects of Common Ownership, 73 J. FIN. 1513 (2018).
José Azar, Sahil Raina & Martin Schmalz, Ultimate Ownership and Bank Competition, 51 FIN. MGMT. 227 (2021).
Martin C. Schmalz, Recent Studies on Common Ownership, Firm Behavior, and Market Outcomes, 66 ANTITRUST BULL. 12 (2021)