Modelling the roles of fourth-party logistics (4PL) on the improvements of supply chain stability of port logistics services: the case of Ningbo-Zhoushan Port in China

This paper examines the challenges and significance of improving contractual cooperation within the supply chain of port logistics services in China. In the context of a port supply chain comprising port enterprises and shipping companies, contractual cooperation serves as a vital coordination mechanism for cost reduction, information sharing, and risk sharing. Additionally, fourth-party logistics providers (4PLs) play a crucial role in enhancing operational efficiency and overall stability. However, the limited rational behavior of individual firms poses challenges to the stability of contractual cooperation. To address these challenges, this study proposes a game model to analyze the evolution of contractual cooperation and identify key factors influencing stability. Practical recommendations are provided to enhance stability and promote the high-quality development of China's port logistics service supply chain. This research contributes to a deeper understanding of the main components of China's port logistics service supply chain, advances the theory of shipping supply chain contracts, and supports China's aspiration to become a global maritime and shipping powerhouse while maximizing global utility.