This study investigates how green investment assets improve optimal portfolio diversification in terms of tail downside risk. We use the wavelet conditional value-at-risk ratio to explore the benefits of adding green assets to conventional portfolios. We quantify risk based on the contagion between conventional stock market indices and green environmental assets, including a sustainability index, clean energy, and green bonds. Our findings emphasize the high variance between conventional stock pairs, providing evidence of contagion effects before and during the COVID-19 pandemic. We show that including clean energy and green bond indices in conventional portfolios reduces the extreme risk of portfolios. In addition, we find that the diversification benefits of clean energy, green bonds, and safe-haven investments apply especially in the short term during the pandemic. Finally, we show that the considered portfolios could not decrease long-term risk during the COVID-19 crisis because of the systematic risk spread. Our portfolio optimization design supports the superiority of clean energy and green bonds in portfolio diversification over the sustainability index. These insights can be used by portfolio managers to inform diversification in different investment horizons.

04:03
This study examines the association between zombie firms and their environmental and social performance. Using a global dataset of listed firms from 49 countries between 2002 and 2019, we find that zombie firms perform poorly on environmental and social responsibility fronts. This finding supports the argument that zombie firms are characterized by consistent losses and that their existence is risky without external support. Zombie firms, while struggling for survival, may not be able to undertake environmental and social activities that require huge investments, thus falling behind other firms. Further analysis highlights that eco-innovation, the presence of a sustainability committee, and industry nature (i.e., heavily polluting industries) mitigate the negative impact of firms’ zombie status on their environmental and social performance. Moreover, a zombie firm’s engagement in environmental and social activities improves its financial performance. Our main findings are robust to a battery of estimation techniques, alternative proxies, selection bias, and endogeneity issues.
MASHWANI Asad Iqbal - EDC Business School |
- Research
- Corporate and Market Finance, Sustainable Development and CSR