Working Papers

“Competitive Effects of State Antitrust Laws: Evidence from the Progressive Era”

Most U.S. states adopted an antitrust statute in the late nineteenth or early twentieth century to regulate anticompetitive conduct and promote competition among firms. However, despite states' pioneering role in the development of antitrust policy, little is known about the economic consequences of their efforts. I estimate the long-term effects of state antitrust laws on manufacturing outcomes using newly digitized state-by-industry data from historical censuses of manufactures. Using difference-in-differences and event study models that account for the staggered nature of adoption, I find that these statutes did little to limit the influence of powerful incumbents. The number of manufacturing establishments rose by about 10 percent following adoption, but evidence on ownership structure suggests that this growth was likely driven by the expansion of incumbent firms rather than new entry. I also find that the labor share declined by about 4 percent overall and by about 7 percent in trust-affiliated industries, suggesting that dominant firms held on to their market power despite new legal constraints on anticompetitive conduct. I find no evidence of increased employment or reduced profits, providing further evidence that firms made few meaningful adjustments to pricing or production behavior in response to these laws. These results suggest that antitrust legislation alone is insufficient to disrupt concentrated market power.

“A Fresh Look at the Origins and Impetus for Antitrust” [with John Mayo]

This paper revisits the origins of antitrust by examining why some states adopted antitrust statutes before the Sherman Act of 1890. We leverage large-scale digitized newspaper data and machine learning methods to measure antimonopoly sentiment during the 1880s and connect these patterns to states’ statutory choices. This analysis allows us to test competing explanations for the rise of antitrust, informing modern debates about the original aims of antitrust policy. Understanding the motivations behind antitrust laws is crucial given that courts continue to rely on legislative intent to guide their interpretation of these statutes. Our findings provide the first quantitative evidence linking contemporaneous public sentiment to legislative outcomes in the pre-Sherman era.