Analyzing the development of competition and cooperation among ocean carriers considering the impact of carbon tax policy

Due to emission reduction pressure and supply chain changes, this paper analyzes the development trend of the marine supply chain based on the competition and cooperation incentives of carriers, considering the impact of the government's carbon tax policy. We consider multistage Stackelberg games with different power structures consisting of a government, hub port, and two carriers. Equilibrium solutions for different power structures show that carriers tend to build alliance and compete with the port for leadership. Higher bargaining power is the dominant choice for all companies, and neither the port nor carrier alliance accepts the other as the leader. Thus, they compromise on equal bargaining. To resolve the conflicting interests of stakeholders, we examine the reasons for revenue-sharing and cost-sharing contracts that cannot coordinate the marine supply chain, and redesign the subsidy and revenue-sharing contracts. Higher subsidies and revenue-sharing proportions can make carriers give up competing for leadership, or even forming an alliance. The contract provides a new solution for companies' strategic decision-making beyond equal bargaining. Numerical analyses suggest that although the contract weakens the effect of the carbon tax, promoting deeper cooperation between companies is a better option for the government. Finally, we verify the reasons for the failure of the carbon tax policy after the government failed to consider the market environment, and summarize the development direction of the marine supply chain under a reasonable carbon tax to provide management insights for stakeholders. Further, the model is extended to prove the validity and robustness of recommendations to the government and companies. New incentives are provided for companies' integrates cooperation.