While studies have examined motivations for businesses to exit and relocate in response to tax and regulatory policies at the state level, no previous work has considered whether U.S. state antitrust enforcement may have similar effects. The results of this article suggest that state-level antitrust (even when coordinated with the federal government) plays a fairly minor role in the exit decision of firms. Where it does play a role, the type of enforcement-anti-cartel vs. other measures-seems to determine the direction of impact. The economic significance of these effects is quite small, however, suggesting that state antitrust authorities need not worry about impacts on the broader economy in their enforcement decisions. Their focus should simply be on the merits of the particular case.