Supplier Diversification and the Expansion of Export Product Scope: Evidence from Chinese Listed Firms

Against the backdrop of increasing global supply chain disruption risks, supplier diversification has emerged as a critical strategy for enhancing economic resilience and sustainable trade performance. Using matched supplier–customer transaction data for Chinese listed firms and Chinese Customs data from 2009 to 2016, this study examines the impact of supplier diversification on firms’ export product scope and its underlying mechanisms. The results show that supplier diversification significantly expands firms’ export product scope by mitigating resource and technological lock-in effects associated with concentrated supply chains. Specifically, a 0.1-unit increase in supplier diversification is associated with an average increase of approximately 0.074 distinct HS 6-digit product categories exported by a firm. Mechanism analyses indicate that this effect operates primarily through promoting technological innovation and reducing production costs. The positive effect is more pronounced among larger firms, firms facing weaker financial constraints, and firms operating in highly competitive or technology-intensive industries. Further analyses show that supplier diversification facilitates the entry of new products into export markets and supports the continued export of existing products, while having no significant effect on product exit. These findings identify supplier diversification as an important micro-level supply-side determinant of firms’ export product scope and provide implications for supplier portfolio design, supply chain resilience, and sustainable export strategies.