How Antitrust Really Works: A Theory of Input Control and Discriminatory Supply

69 Pages Posted: 1 Mar 2021

See all articles by Ramsi Woodcock

Ramsi Woodcock

University of Kentucky College of Law

Date Written: February 28, 2021


Antitrust law and policy today are a semi-coherent welter of legal and economic doctrines. Immanent in them, however, is a structure of great simplicity and utility. The concept at the heart of the antitrust laws is the linear supply chain, consisting of an essential input, a downstream market in which competition is harmed through the discriminatory supply of the input to downstream firms, and consumers who pay higher prices for finished products as a result of the discriminatory behavior. Antitrust attacks this problem of the discriminatory supply of inputs in two ways. First, it seeks to prevent any one intelligence from taking control over the input, because absent such centralized control, competition from input suppliers eliminates any attempt at discrimination. Stopping the centralization of control over inputs is not always possible, however, because sometimes centralized control improves the quality of the input, and antitrust follows an implicit rule of “innovation primacy,” which holds that any act that plausibly improves the product likely does more good for consumers than any resulting increase in prices harms them, and so the act must be immune from antitrust scrutiny.

Second, antitrust regulates attempts by input controllers to use their power to increase their profits other than by charging what they know to be the highest possible prices for their products given their level of knowledge of consumer willingness to pay. Profits can be increased in this way by only three routes, each of which involves discrimination by the input controller in the supply of inputs to downstream firms. The input controller can discriminate in favor of firms that improve the final product ultimately sold to consumers and so increase consumers’ willingness to pay. The input controller can discriminate in favor of downstream firms that supply the input controller with information about consumer willingness to pay, enabling the input controller better to choose its prices to maximize its profits. And the input controller can discriminate against downstream firms that refuse to give the input controller access to profits that the firms have in turn extracted from consumers. The doctrine of innovation primacy protects discrimination that improves the final product sold to consumers, but not discrimination that facilitates information acquisition or the disciplining of refractory downstream firms.

This analysis resolves numerous longstanding conundrums in antitrust, including (1) whether antitrust picks winners (it must), (2) whether picking winners limits consumer sovereignty (impossible, because whenever a firm discriminates in the supply of inputs, the firm picks winners, and antitrust, which does no more than challenge such discrimination, therefore only ever substitutes its judgment for that of firms, never for that of end consumers), (3) whether antitrust should have a monopoly power requirement (it should, but the requirement should apply to the input market and not, as at present, to the downstream market in which competition is harmed), (4) whether firms should be allowed to compete on their own platforms as a general matter (of course they should, unless it is thought that consumers always know better than firms how everything they buy should be made, from start to finish), and (5) how to define the limits of the firm (the boundary of the firm does not end where formal ownership ends, but rather where discrimination in the supply of inputs ends). The analysis also shows why Lorain Journal, Aspen Skiing, Linkline, Trinko, Microsoft, Qualcomm, exclusive dealing, and tying are all the same basic case.

Suggested Citation

Woodcock, Ramsi, How Antitrust Really Works: A Theory of Input Control and Discriminatory Supply (February 28, 2021). Available at SSRN: or

Ramsi Woodcock (Contact Author)

University of Kentucky College of Law ( email )

620 S. Limestone Street
Lexington, KY 40506-0048
United States

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