Policymakers claim that combating tax avoidance can help reduce industry concentration by leveling the playing field between industry leaders and their competitors. We test the validity of this claim by using administrative data on industry concentration and exploiting the staggered introduction of anti-tax avoidance regulations across 17 European countries. Although these regulations significantly reduce tax avoidance, we find no statistically or economically meaningful effect on industry concentration. Further tests indicate that our nonresults stem from a genuine lack of effect rather than a lack of statistical power and that our inferences are robust to multiple research designs. The sole exception is in industries with both high levels of leader tax-avoidance advantages and multinational presence, but even in these industries, effect sizes are modest and fall short of regulatory benchmarks. Overall, our findings cast doubt on the idea that broad-based anti-tax avoidance regulations can materially influence industry concentration.