Green taxes: Productivity effects of tax-based environmental regulations on heavily polluting firms

Environmental regulations, particularly tax-based measures, significantly impact firm productivity and corporate behavior. This study uses China's Environmental Protection Tax (EPT) law as a quasi-natural experiment to explore whether and how such tax-based environmental regulations influence the productivity of heavily polluting firms. Using a difference-in-differences approach, we find that the EPT law has positively impacted firm productivity by fostering higher research and development investments and encouraging the substitution of labor with capital. The productivity-enhancing effect is more pronounced for state-owned enterprises, large firms, firms with fewer financial constraints, firms receiving more government subsidies, and firms operating in less competitive sectors. These findings support the Porter hypothesis, suggesting that well-designed environmental regulations can stimulate innovation and improve competitiveness, ultimately enhancing productivity. This study underscores the importance of tax-based environmental regulations in promoting productivity and economic growth, providing valuable insights for policymakers aiming to balance environmental protection with economic development.