Public Procurement and University-Industry Research Collaboration: The Mediating Role of R&D Investment and the Moderating Role of Financing Constraints

University–industry research collaboration is an important pathway through which firms integrate external scientific knowledge, strengthen innovation capabilities, and develop sustainability-oriented technological solutions. Public procurement, as a demand-side policy instrument, may provide market demand, resource expectations, and policy signals that encourage firms to cooperate with universities and research institutes. However, whether public procurement is associated with firms’ university–industry research collaboration remains insufficiently examined. Based on Chinese A-share listed firms from 2013 to 2024, this study matches public procurement contract data with listed firms and their subsidiaries and constructs firm-year measures of public procurement. University–industry research collaboration is measured by co-applied patents between firms and universities or research institutes. The baseline two-way fixed-effects results show a positive and statistically significant association between public procurement scale and university–industry research collaboration, although the estimated magnitude is economically small. Additional count-data and selection-adjusted analyses provide partial support for this relationship, but the results are not fully consistent across all specifications. The mechanism analysis provides suggestive evidence that R&D investment scale may serve as a channel through which public procurement is related to collaborative research activities. Further analysis shows that financing constraints positively moderate this relationship, and ownership heterogeneity indicates that the association is stronger among state-owned enterprises. These findings suggest that public procurement should not be understood as a uniformly effective driver of university–industry collaboration. Rather, its role appears to depend on firms’ financial conditions and institutional characteristics. This study contributes to research on demand-side innovation policy, university–industry collaboration, and sustainable innovation systems by highlighting the conditional nature of the procurement–collaboration relationship.