Influence of the Carbon Emissions Trading Policy on Green Patent Transfers: A Difference-In-Differences Design

The transfer of green patents, including patent assignments and patent licensing, is meaningful for the diffusion of green innovations to realize low-carbon development and carbon emission reduction. China introduced pilot carbon emissions trading policy (CETP) in 2011, which plays an important role in guiding the reallocation of green patents. Based on panel data of A-share listed firms in China from 2008 to 2022, this study uses the time-varying difference-in-differences (DID) method to examine the influence of the CETP on green patent transfers. The results show that the CETP has significantly facilitated green patent transfers, indicating the important role of market-based mechanisms in promoting the diffusion and application of green innovations. Firms with different technical histories behave differently. Green firms tend to sell green patents, and non-green firms tend to buy green patents, while mixed firms do both. In addition, environmental regulations negatively moderate green patent transfers effect of CETP, whereas R&D investment plays a mediating role. The heterogeneity analysis suggests that CETP has a more obvious impact on green patent transfers for non-state-owned firms, and those operating in the eastern region of China. Finally, we suggest that policymakers can make full use of market-based mechanisms to facilitate green technology transfers considering firm heterogeneity.