Connectedness between green bonds, conventional bonds, oil, heating oil, natural gas, and petrol: new evidence during bear and bull market scenarios

This study examines the spillovers between US green bonds, non-green bonds (10-year US Treasuries) and four major energy markets - West Texas Intermediate (WTI) crude oil, heating oil, natural gas, and petrol - during bear and bull market conditions. We combine the Diebold and Yilmaz (2012) spillover index and the quantile connectedness approach developed by Ando et al. (2022) in order to capture financial markets exhibiting higher potential risk and to assess their extreme dependence. The main results show a strong time-varying connectedness between focal asset classes during major crisis periods, including the oil price crash, the China-US trade conflict, the coronavirus crisis and the war between Russia and Ukraine. The network analysis reveals that WTI, heating oil and green bonds act as net transmitters of risk, while the other asset classes serve as net receivers of spillovers. In extreme conditions, spillovers between energy commodities, green bonds and non-green bonds are asymmetric, given that they are not equal in the upper and lower quantiles. Green bonds offer greater diversification benefits when coupled with WTI, heating oil, gasoline, and natural gas, though with varying portfolio weights.