Sustainable Shipping Development and the Optimal Green Finance Portfolio: A Case Study of Taiwan’s Sustainable Shipping and Financial Market Development

Smart shipping and achieving net-zero emissions have become pressing priorities in maritime transport, yet limited research has integrated sustainable shipping development with green finance decision-making. To address this gap, this study applies the AHP–RDEMATEL–TOPSIS approach to analyze the interrelationships and relative importance of key sustainability factors and to identify optimal green financing instruments. Incorporating ESG dimensions, the research conducted a survey of large international exporters in Taiwan and senior managers of shipping companies. The results reveal that green infrastructure is the most critical factor for container shipping lines, while energy efficiency and renewable energy technologies are dominant for bulk carriers and shippers. Corporate reputation and image emerge as primary factors impacted across all three groups. In financing decisions, green bonds are most suitable for container lines, whereas green equities are best suited for bulk carriers. This study bridges the theoretical gap between sustainability assessment and finance, providing practical guidance for shipping companies’ financial departments seeking to align decarbonization goals with effective green financing solutions. Ultimately, the primary contribution of this study lies in establishing an empirically validated, multi-criteria decision support framework that empowers maritime stakeholders to systematically optimize their green investment portfolios amid the global transition towards net-zero emissions.