Digital finance enhances corporate ESG performance and is essential for achieving sustainable development; however, its consistent effectiveness in improving ESG outcomes remains contested. Using panel data from A-share listed companies on the Shanghai and Shenzhen stock exchanges in China from 2011 to 2021, this study empirically examines nonlinear effects, transmission mechanisms, and moderating factors. The results indicate a U-shaped relationship between digital finance and ESG performance, with a positive impact becoming apparent when digital finance exceeds the threshold of 3.81. Mechanism tests reveal that green technological innovation and public environmental attention are crucial transmission channels for the nonlinear effects. Furthermore, financial regulation levels and environmental uncertainty negatively moderate this relationship, while corporate digital transformation has a positive moderating effect. Further analysis shows that the U-shaped relationship is more pronounced in areas with lesser financial advancement and higher levels of environmental regulation, as well as in non-high-tech industries, non-manufacturing sectors, smaller firms, and companies without political connections. This study provides empirical evidence and policy insights to support the promotion of financial services that better facilitate corporate sustainability.

The deep integration of digital finance and foreign trade can drive the steady and rapid development of a high-quality economy. This article conducts an empirical analysis of the mechanisms and impact effects of digital finance on high-quality development of foreign trade (HDFT) using panel data from 30 provinces in China (excluding Tibet, Hong Kong, Macao, and Taiwan) from 2011 to 2021. The research demonstrates that digital finance significantly promotes HDFT and facilitates the achievement of sustainable development goals while enhancing financial development levels and infrastructure to advance the quality of foreign trade further. Heterogeneity test results reveal that the effectiveness of digital finance varies across regions with different financial development levels. The study also identifies threshold effects in the relationship between digital finance and HDFT, with investment environments and internet penetration rates dynamically reinforcing the sustainability of digital finance in driving HDFT.