A coauthored paper by Professor Keigo Kameda of the School of Policy Studies and his undergraduate seminar students on environmental bonds has been published in the international academic journal International Review of Financial Analysis. The study employs both a difference-in-differences approach and an event study methodology to conduct causal inference on the impact of three types of ESG bonds—green bonds, sustainability bonds, and sustainability-linked bonds—on firms’ CO₂ and water emissions. The results indicate that while green bonds effectively reduce environmental impact, the other two types show no significant effect. This difference is attributed to the strict restrictions on the use of proceeds associated with green bonds, which are not imposed on the other two types.

The paper offers important insights for the future design of environmental bond frameworks and relevant policy measures.

This research originated from a seminar report written in their third year by three students who later graduated in the spring of 2024. The report was presented at the ISFJ (Inter-university Seminar for the Future of Japan) Policy Forum. The paper was subsequently expanded into its current form by Mr. Shimauchi—the first author—who incorporated analyses of sustainability bonds and sustainability-linked bonds into his graduation thesis. After his graduation, the research was continued by Mr. Fukui, now a graduate student and currently a researcher at the Policy Research Institute of the Ministry of Finance, Japan. This paper represents the world’s first empirical analysis of the environmental effectiveness of sustainability bonds and sustainability-linked bonds, and it deserves high recognition.
Professor Kameda, the corresponding author and supervising faculty member, commented, “These results demonstrate the strength of undergraduate education at the School of Policy Studies. I hope this aspect will be duly recognized.”