Research on the Impact of Tax Incentives on Corporate Greenwashing Behavior: Quasi-natural Experiment Based on Value-Added Tax Refund Policy for Input Tax Credits

China has long relied on tax incentive tools to guide enterprises in green transformation, and the value-added tax (VAT) refund policy for excess input tax credits has become an important policy instrument in the fiscal and taxation regulatory system. Taking A-share listed companies in Shanghai and Shenzhen as research samples, this paper treats the gradual implementation of the VAT refund policy from 2018 to 2023 as a multi-period exogenous shock, and conducts an empirical test using the multi-period difference-in-differences model. The results show that the VAT refund policy significantly inhibits corporate greenwashing behavior through dual channels: on the one hand, the policy eases financing constraints by refunding input tax credits, thereby reducing enterprises' willingness to seek external resources through greenwashing; on the other hand, the policy strengthens regulatory effectiveness through the tax refund review process, compressing the operational space for corporate greenwashing. Heterogeneity tests indicate that the inhibitory effect is more pronounced in enterprises with low environmental investment, high VAT refund intensity, and high baseline greenwashing levels. This paper enriches the research perspective for the intersection of tax incentives and environmental governance, and provides empirical evidence for optimizing green tax policies and restraining corporate greenwashing behavior.