The Spillover Effect of National Auditing on the ESG Performance of Supply Chains: Empirical Evidence from the Quasi-Natural Experiment of China’s NAO Auditing SOEs

Supply chains play a crucial role in achieving the Sustainable Development Goals (SDGs) through the improvement of ESG performance. From the perspective of synergy between national auditing and corporate governance, this study integrates the SDGs into the supply chain ESG strategy and evaluates the spillover effects of national auditing on supply chain ESG performance, drawing on the quasi-natural experiment of China’s National Audit Office (NAO) auditing state-owned enterprises (SOEs). The findings illustrate that national auditing has a significant positive spillover effect on the ESG performance of supply chains. These findings remain robust after addressing potential endogeneity via placebo tests, PSM-DID, and Heckman two-step method. Heterogeneity analysis highlights that supply chains with strong cooperation stability, high concentration, and presence in the same industry have more pronounced ESG spillover effects. Mechanism analysis further demonstrates that national auditing enhances the ESG performance of supply chains by exerting imitative, mandatory, and normative pressures. Moreover, audit regulatory agencies should establish a mechanism for sharing audit results to exert mandatory institutional pressure, thereby ensuring this mechanism enables audits to fully fulfill their role in improving supply chain ESG performance.