As investors increasingly buy ESG funds, there has also been an increase in academic research on the impact of implementing ESG constraints on equity portfolios. However, there hasn't been as much attention paid to research on ESG fixed-income investing. Inna Zorina and Lux Corlett-Roy published their study “The Hunt for Alpha in ESG Fixed Income: Fund Evidence from Around the World,” in the Fall 2022 issue of The Journal of Impact and ESG Investing. In the study, they examined whether ESG fixed-income funds generate out- or under-performance after controlling for systematic fixed-income factors. They found that while ESG fixed-income funds with a higher level of risk generally produced higher returns, most ESG fixed-income funds did not produce statistically significant positive or negative gross alphas. In fact, only 7% of funds managed to deliver greater returns at a lower level of risk relative to the respective benchmark. The study revealed that across ESG fixed-income funds with a European, U.S., and global focus, performance was mainly driven by systematic fixed-income factor exposures such as term and default risk. The results led Zorina and Corlett-Roy to conclude: “ESG fixed-income mutual funds and ETFs have not consistently delivered statistically significant gross alpha controlling for key fixed-income factors. The majority of alphas are statistically insignificant and therefore indistinguishable from zero. This conclusion is similar across fixed-income funds with a European, US, and Global ESG investment focus.”

Finsum:A recent study that looked into whether fixed-income ESG funds provided outperformance revealed that ESG fixed-income mutual funds and ETFs have not consistently delivered statistically significant gross alpha.