JOURNAL: Rethinking greenium: a quadratic function of yield spread

Summary

Authors:

Chih-Yueh Huang
David Dekker
Dimitrios Christopoulos

Heriot-Watt University
MODUL University Vienna

Rethinking greenium: a quadratic function of yield spread

Finance Research Letters

June 2023

This research suggests a new approach to the estimation of the ‘greenium,’ the difference in value between green bonds and similar non-green bonds. Instead of using the usual method of comparing the yields of these bonds, the research shows the value of understanding the greenium as a function of non-green bond yield spread.

The research shows that the greenium increases when the difference in yields between non-green bonds is larger – so, the bigger the difference in yields between non-green bonds, the larger the greenium. Additionally, it foregrounds how increase isn’t steady: it accelerates as the difference in yields between non-green bonds grows. The research also finds that this non-linearity accounts for the effects of credit spread and coupon rate.