Research on the Impact of Green Financial Reform and Innovation Pilot Zone Policy on Corporate Debt Financing Costs-Evidence from a Multi-period Difference-in-Differences Model

With the continuous advancement of the "Dual Carbon" goals, green finance has emerged as a critical policy instrument designed to channel social capital toward green and low-carbon sectors. It is imperative to conduct an in-depth evaluation of the effects of pilot policies implemented in green financial innovation pilot zones. Utilizing panel data of A-share listed companies spanning from 2011 to 2025 as research samples, this study constructs a multi-period difference-in-differences (DID) model to systematically investigate the impact of the Green Financial Innovation Pilot Zone policy on corporate debt financing costs. The empirical findings demonstrate that the pilot zone policy significantly reduces debt financing costs for enterprises located within the designated regions. Heterogeneity analysis reveals that this cost-mitigating effect is considerably more pronounced for privately owned enterprises, whereas no statistically significant influence is observed among state-owned enterprises. These results suggest that the policy framework effectively lowers borrowing costs, particularly for non-state-owned firms that traditionally face greater financing constraints. Based on these findings, the study recommends that pilot zones should continuously diversify the supply of green financial products, strengthen environmental information disclosure systems, and implement differentiated green credit arrangements. Such measures would maximize the supportive role of green finance in facilitating enterprise financing, particularly for private firms, and ultimately accelerate the green transformation and sustainable development of enterprises across China.