Organization, Control, and the Single Entity Defense in Antitrust

Posted: 22 Dec 2009

Multiple version iconThere are 2 versions of this paper

Date Written: December 2009


Since at least the 1930s, economists have puzzled over how to delineate the boundaries of a firm. With the advent of antitrust legislation in 1890, American courts have been pressed to consider what constitutes conspiracies between corporate entities to restrain commerce. By the 1980s, courts started to characterize conspiracies by negation-that is, by extending the status of “single entity” to certain types of agglomerations. Efforts both in economics and in the law to sort out what constitutes a “firm” or “single entity” have focused on “control.” A difficulty is that neither the law nor economics offers an operationally significant concept of control. Even so, both the law and economics contribute concepts other than control that provide a way of understanding economic organization. These concepts-adaptation and control rights-suggest how one can subsume the sometimes confusing array of single entity tests proposed in the case law within a two-stage sequence of tests.

Keywords: D23, K21, L49

Suggested Citation

Williamson, Dean V., Organization, Control, and the Single Entity Defense in Antitrust (December 2009). Journal of Competition Law and Economics, Vol. 5, Issue 4, pp. 723-745, 2009, Available at SSRN: or

Dean V. Williamson (Contact Author)

Independent ( email )

Washington, DC
United States

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