senior fellow and holds the Milton Friedman Chair at the American Enterprise Institute.

The article examines the complex outcomes of antitrust actions against dominant technology platforms, focusing on a study of the landmark U.S. antitrust case against Microsoft in the late 1990s and early 2000s. It finds that while regulatory intervention increased technical innovation, measured by patent activity, it did not lead to greater product commercialization, profitability, or new market entrants, with smaller complementor firms often suffering the most. The research highlights challenges in platform ecosystems where dominant firms may favor their own offerings, and cautions regulators that promoting innovation alone does not guarantee enhanced competition or consumer benefits. The findings suggest that both complementors and platforms should prepare for shifts in market dominance, and that antitrust remedies need careful design to avoid unintended consequences.