ANTICOMPETITIVE DIRECTORS - Columbia Law Review

Antitrust scholars have virtually ignored the question of who controls corporations by sitting on their boards of directors. We show that the problem of who sits on boards of directors is considerably greater than previously believed. Drawing on a new dataset spanning both public and private companies across multiple industries, we find evidence that individual board members sit simultaneously on boards of competitors throughout the economy, despite such “interlocking directorates” being illegal under antitrust law. Many of these individuals are senior directors at private equity, venture capital, and other firms investing in the competing firms on whose boards they sit. We rely on a proprietary dataset used by investment firms that identifies actual competitors, rather than just adjacent firms in the same industry.

But the same individual sitting on two competing boards isn’t the only problem. We are the first to show the prevalence across public and private companies of a related problem—two different individuals sitting on competitors’ boards while simultaneously working at the same investment fund. We show that such investor-level interlocks are more common than individual interlocks, yet their prevalence was, until now, unknown. About 13% of the companies for which we have the best board data had either an individual or investor-level interlocking board.

Individual and investor-level interlocking boards can harm competition and innovation. We propose either applying existing antitrust laws more vigorously or reforming the law to reach these investor interlocks.

The full text of this Article can be found by clicking the PDF link to the left.

* J.D. 2025, Stanford Law School.

** William H. Neukom Professor, Stanford Law School; Partner, Lex Lumina LLP.

*** Professor of Law, Boston University School of Law; Affiliated Fellow, Yale Law School Information Society Project; Faculty Associate, Berkman Klein Center at Harvard Law School. We thank Bobby Bartlett, Michael Carrier, Ofer Eldar, Robin Feldman, Daniel Francis, Jeffrey Gordon, Rose Hagan, Doug Melamed, Mike Meurer, and Tim Wu for comments on a prior draft and PitchBook for access to its data. The order of authors was assigned randomly. © 2025 Lane Miles, Mark A. Lemley & Rory Van Loo.

“The practice of interlocking directorates is the root of many evils. It offends laws human and divine.”

— Justice Louis Brandeis.

Louis D. Brandeis, Interlocking Directorates, in Other People’s Money and How the Bankers Use It 51, 51 (1914).

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Introduction

Antitrust law prohibits competing corporations from sharing board members (so-called “interlocking directorates”) and has for more than a century.

Clayton Antitrust Act of 1914, ch. 323, § 8, 38 Stat. 730, 732–33 (codified as amended at 15 U.S.C. § 19 (2018)).

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The main idea is that if the same person serves on the boards of two competing companies, they may discourage one of their companies from competing vigorously against the other, and the information and connections they have make it easier for those companies to collude.

See Julian O. von Kalinowski, Peter Sullivan & Maureen McGuirl, 2 Antitrust Laws and Trade Regulation § 35.02[1] (2d ed. 2024) (noting the primary rationale for prohibiting interlocking directorates was that Congress viewed them as stifling competition; additional rationales included eliminating potential conflicts of interest among directors and creating business opportunities for individuals).

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So we prohibit people from serving on the boards of companies that compete even in part.

See 15 U.S.C. § 19(a) (“No person shall, at the same time, serve as a director or officer in any two corporations . . . that are . . . engaged in whole or in part in commerce; and . . . competitors . . . .”).

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It’s a simple rule—one that is easy to observe—and violating it is one of the few things antitrust declares illegal per se, with no opportunity to explain or justify the interlock.

See United States v. Sears, Roebuck & Co., 111 F. Supp. 614, 616–17, 621 (S.D.N.Y. 1953) (holding no anticompetitive effect need be shown to establish section 8 liability under the Clayton Antitrust Act).

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We show that large numbers of companies are directly violating that law and that the problem goes well beyond simply breaking the law. Using a dataset that enables us to provide the first analysis of board members on both public and private companies—rather than just public companies

Prior work necessarily focused only on publicly traded companies due to data limitations. See Anoop Manjunath, Nathan Kahrobai, Mark A. Lemley & Ishan Kumar, Illegal Interlocks Among Life Science Company Boards of Directors, J.L. & Biosciences, Jan.–June 2024, at 1, 9 [hereinafter Manjunath et al., Illegal Interlocks] (acknowledging the dataset limitation to publicly traded companies); Yaron Nili, Horizontal Directors, 114 Nw. U. L....