The Effects of the Development Zone Upgrading on the Diversification of Firm's Product Exports: Evidence from Chinese Exporters

Against the backdrop of frequent international trade frictions, reducing external risks in export trade through industrial policies has become crucial for China's high-quality and steady foreign trade development. This paper examines the impact of development zone upgrading policies on the diversification of firm product exports by using a time-varying difference-in-differences model. We find that after the upgrading of development zones, the diversification of firm product exports increases by 2.13%, and concentration decreases by 1.33%. Moreover, this policy has a stronger impact on the diversification level of product exports for firms upgraded to customs special supervision areas, located inland, and engaged in general trade. These conclusions remain robust even after conducting additional robustness tests using alternative measures of the dependent variable, different identification methods for development zone upgrading, and controlling for other industrial policy effects. Furthermore, the upgrading of development zones improves export diversification through three main channels: enhancing firm innovation capabilities, optimizing management efficiency, and providing financial support to firms.