Anticompetitive Entrenchment

32 Pages Posted: 30 Jan 2020 Last revised: 21 Jul 2020

See all articles by Sean Sullivan

Sean Sullivan

University of Iowa College of Law

Date Written: 2020


Mounting public concern with the exercise of market power in concentrated markets demands a response. While modern antitrust emphasizes the prevention of market power over reaction to its exercise, it does contain one indirect but potentially important tool for addressing problems with already existing concentration and market power: the often-overlooked theory of resistance to anticompetitive entrenchment in merger enforcement. This article explores how traditional concerns with the entrenchment of market power might be updated and reintroduced to serve as a vehicle for addressing problematic markets in the modern antitrust framework. The article explains this theory of anticompetitive entrenchment, its limits, and appropriate conditions for its use, in the context of two specific applications: (1) tacit collusion among oligopolists, and (2) the exploitation of market power by a dominant firm in a protected position.

Keywords: entrenchment, antitrust, concentration, market power

JEL Classification: K21, L41

Suggested Citation

Sullivan, Sean, Anticompetitive Entrenchment (2020). Kansas Law Review, Vol. 86, 2020, Available at SSRN: or

Sean Sullivan (Contact Author)

University of Iowa College of Law ( email )

Melrose and Byington
Iowa City, IA 52242
United States


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