Green innovation constitutes a core driver of green economic transformation. China has witnessed a rapid expansion in green patent applications in recent years, but deficiencies remain in terms of innovation quality and breakthrough capacity. Therefore, identifying the key factors that can effectively motivate firms to engage in high-quality green innovation has theoretical and practical importance for advancing green transformation and achieving high-quality economic development.

Based on a sample of China’s A-share listed companies from 2010 to 2024, this paper uses institutional investor holding records and holding-duration data to identify patient capital, and examines the impact of patient capital support on corporate green innovation quality and its underlying mechanisms. The results show that patient capital significantly improves corporate green innovation quality, and this effect persists even after patient capital exits. Mechanism testing indicates that patient capital affects green innovation quality by strengthening sustainability awareness, alleviating financing constraints, and enhancing tolerance for failure. Further analysis shows that national policies reinforce the positive role of patient capital, suggesting a complementary relationship between national policies and market forces in promoting high-quality green innovation. In addition, the promoting effect of patient capital on green innovation quality is more pronounced among firms with weaker internal and external governance, smaller-scale firms, and firms operating in more competi- tive industries.

This paper makes the following contributions: First, it extends the measurement of patient capital from a time-dimension perspective. Drawing on more than four million institutional investor holding records from 2000 to 2024, this paper identifies patient capital on the basis of continuous holdings of 10 or 15 years and constructs a measure that better captures its long-term and stable nature. Second, it broadens the research perspective on the role of patient capital in green innovation by shifting the focus from the quantity of green innovation to its quality, and by further examining whether the effect of patient capital persists after its exit. Third, it analyzes the internal mechanisms through which patient capital affects green innovation quality from three dimensions, providing new evidence on how capital attributes shape green innovation quality. Fourth, it further investigates the external conditions under which patient capital exerts its effect and examines how national policies interact with market-driven patient capital, offering policy implications for improving the institutional support system for patient capital and promoting high-quality green innovation.