Digital–Green Governance Synergy and Corporate Sustainability Performance: A Quasi-Natural Experiment Based on the Dual Policies of Public-Data Openness and Green Data Centers

Against the background of coordinated digital and green transformation, this study uses data on Shanghai- and Shenzhen-listed A-share firms from 2010 to 2024. The first year in which both policies take effect in a firm’s city is taken as the coordinated policy shock year. Using a staggered difference-in-differences (DID) model and double machine learning (DML), this study evaluates how public-data openness and green data center policies affect corporate sustainability performance. The results indicate that entering dual-policy status significantly improves corporate sustainability performance. Further restricted-sample analysis documents a positive incremental dual-policy effect beyond a single-policy implementation, which provides suggestive evidence for theoretical policy complementarity. Mechanism tests reveal that dual-policy status is associated with enhanced credit availability, greater ambidextrous green innovation, reduced agency costs, and optimized human-capital allocation. These patterns provide suggestive evidence consistent with the four theoretically proposed transmission channels, though formal causal mediation is not established in the current empirical setup. Analysis based on the technology–organization–environment (TOE) framework shows that technological foundations, organizational capabilities, and the external green institutional environment all strengthen the policy synergy effect. Further analysis has found that each policy has a positive effect when implemented separately; compared with a single-pilot status, the dual-pilot status produces a significant positive net effect. Both implementation sequences generate positive synergy effects; based on the point estimates, the synergy effect is larger when green data centers are built before public-data openness is promoted. From a policy-combination perspective, this study reveals the complementary mechanism between data element supply and green computing capacity and provides firm-level evidence for the coordinated advancement of digitalization and greening.