Transforming maritime supply chains through digital port policies considering ESG: an evolutionary game theoretical framework with empirical analysis

Recent years have witnessed the growing influence of emerging digital port policies (DPPs) on the maritime shipping industry. These policies have had mixed impacts on firms’ profitability, with the effects varying according to their ESG (Environmental, Social, and Governance) profiles. Motivated by this, this study investigates how DPPs affect port and carrier profits under different ESG conditions. We employ two main approaches: (1) a government–firm evolutionary game theoretical framework with ESG heterogeneity, and (2) empirical analysis based on event study methodology. The theoretical models reveal optimal DPP strategies for governments and identify two stable ESG-related equilibria under varying market scenarios. Key factors such as tax rate and cost coefficient are found to influence equilibrium outcomes. Empirically, we analyze 129 listed maritime firms in China’s A-share market and compare two representative DPPs issued in 2019 and 2023. Results show that the 2019 policy had a negative impact on firm profitability, whereas the 2023 policy produced a positive effect. This phenomenon is consistent with the predictions derived from our theoretical models. Finally, we find that a firm’s ESG level plays a positive moderating role in the relationship between DPPs and firm performance. These findings can provide useful implications for the development and refinement of digital port policies.