Supply chain finance to improve the financing efficiency of SMEs under green credit and government supervision

Improving the financing efficiency and green transformation of small and medium-sized enterprises (SMEs) through supply chain finance and government supervision has become critical for high-quality economic development. This study constructs a tripartite evolutionary game model involving enterprises, banks and governments, employing numerical simulation to examine how green credit policies, government supervision and public environmental concern influence SMEs’ green production behaviour. The key findings reveal: (1) Government subsidies and publicity significantly enhance green transformation probability only when transformation costs are simultaneously reduced; (2) Targeted green credit subsidies shorten banks’ convergence to stable green lending strategies by approximately 30%; (3) Reducing supervision costs effectively improves government regulatory performance, whereas intensified administrative penalties yield only short-term effects; (4) Enhanced public environmental awareness promotes both enterprise green transformation and government performance, particularly in low-cost environments. These findings provide quantified, sensitivity-tested policy recommendations, demonstrating that effective green finance reform requires coordinated policy portfolios calibrated to specific transformation cost scenarios rather than isolated interventions.