Hub-Plucking, Hub-Contestability, and Hub Power: Harnessing Network Science to Rethink Antitrust’s Analysis of Platform Competition

Raz Agranat

Publication Date

12-2025

Document Type

Dissertation

First Advisor

Omri Ben-Shahar

Second Advisor

William H. J. Hubbard

Third Advisor

Eric Posner

Abstract

This JSD dissertation develops a framework for understanding competition within platform ecosystems by uncovering the structural and strategic role of hubs—highly connected nodes within these ecosystems. Drawing on contemporary network science, a computational discipline devoted to studying complex systems, it argues that hubs are not merely participants but critical loci of value creation and control. Their behavior can determine the competitive trajectory of the ecosystem and shape inter-platform rivalry. Network science shows that social, technological, biological, and economic systems follow common organizing principles, which the dissertation leverages to examine the emergence, strategic behavior, and contestability of hubs, thereby reconfiguring how market power should be understood in digital ecosystems. The first article, Uncovering the Role of Hubs: A Network Science Perspective on Platform Competition, challenges the entrenched dichotomy that views network effects as either inevitably leading to winner-takes-all outcomes or as inherently self-correcting. Drawing on concepts such as preferential attachment and node fitness, it introduces hub-plucking—the rivalry between platforms over highly connected nodes—and shows that this overlooked dynamic lies at the heart of digital competition. The second article, Hub-Contestability: A New Antitrust Paradigm for Platform Competition, advances the concept of hub-contestability to counter the threat posed by network effects entrenching dominant platforms. It builds on the insight that the seemingly insurmountable moat created by network effects contains a critical vulnerability to hub-plucking competition, yet cautions that dominant platforms may neutralize this threat through tactics aimed at locking, crushing, or suppressing hubs. By fusing network science with contestability theory, hub-contestability seeks to recalibrate antitrust doctrines—from merger control and abuse of dominance to remedies—so that hubs remain sufficiently contestable to sustain dynamic inter-platform competition. The final article, Hub Power and Hub(uses): Power Dynamics in Platform Ecosystems, examines the reverse phenomenon: the rise of hub power within platforms. It identifies four determinants—hub attractiveness, platform dependence, switching feasibility, and countervailing power—and demonstrates how dominant hubs can distort value creation and competition both within and across platforms. Through case studies spanning e-books, social media, streaming, and air travel, it shows how hub power reshapes market outcomes and complicates antitrust intervention. Together, these studies develop a unified framework for understanding competition in the networked economy. By revealing how hub dynamics both constrain and enable platform power, the dissertation bridges network science and antitrust law—laying the groundwork for a new generation of competition analysis attuned to the complex architecture of digital ecosystems.

https://doi.org/10.6082/uchicago.16541

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