Green supply chain management and low-carbon innovation spillover effects

Supply chain partnerships are an essential component of business innovations. This study uses data on A-share listed companies on the Shanghai and Shenzhen stock exchanges from 2012 to 2022 to conduct a multi-period difference-in-differences analysis based on a list of green supply chain management (GSM) companies. We find that GSM significantly promotes low-carbon technology innovations (LCT) of upstream enterprises. The mechanism analysis indicates that GSM has a resource effect and signal effect that generate LCT spillovers. In terms of the resource effect, GSM companies offer green credit and support green procurement, thereby providing financial support for green investments in upstream LCT. In terms of a signaling effect, GSM strengthens the effectiveness of institutional investors, the public, and online media in supervising upstream suppliers’ green credentials, thereby promoting upstream LCT. A heterogeneity analysis shows that when midstream companies are state-owned enterprises or industry leaders, and when the concentration and stability of supply chain purchase relationships are higher, the LCT spillover effects of GSM are more pronounced. Further analysis reveals that GSM has bidirectional horizontal spillover effects and that upstream unidirectional vertical spillover effects are limited to first-level suppliers. Additionally, under the premise of not compromising economic benefits and stability, GSM shows an emerging trend of transitioning from environmentally compliant “light green” supply chains to “deep green” supply chains focused on pollution reduction, carbon reduction, and energy conservation.