In the field of sustainable finance, Environmental-, Social- and Governance-ratings (ESG) have become an acknowledged measurement of a firm's sustainability performance. The increased awareness of sustainability issues in today's society is undeniable. However, based upon contradicting results from previous research, it was uncertain if investors were rewarding a firm’s sustainability efforts in the form of a lower cost of equity. The purpose of this thesis has therefore been to examine the relationship between sustainability, risk and valuation as well as stock-price behavior in times of crisis regarding large firms publicly listed in the Nordic countries. In order to fulfil the purpose, various multiple regression models have been conducted on quarterly data from the period between 2011 to 2020. The approach chosen to examine if ESG has a relation to the cost of equity has been to calculate the implied cost of equity inferred from consensus forecasts of future financial development and stock price at each point in time, also known as the ex-ante cost of equity. Since the independent variable ESG-score was not likely to be the sole variable to affect the independent variables in our multivariate regression models, we have followed previous studies in the choice of control variables. The empirical results of this study showed a significantly negative relationship between a firm’s ESG-score and the cost of equity. In addition, our results showed a significantly positive relationship between a firm’s ESG-score and both the price-to-earnings ratio as well as the price-to-book ratio while no significant relationship between a firm’s ESG-score and the enterprise value to earnings before interest and taxes ratio could be established. Finally, the results of this thesis showed that firms with a greater ESG-score generated excess returns during the latest market turmoil of 2020 caused by the Covid-19 outbreak. This thesis challenges the value-destruction view of ESG-efforts since our results indicate that investors are pricing sustainability risk with a negative risk premium in line with the value creation approach. No causality test has been performed during this study, however several possible mechanisms by which ESG impacts the valuation and crisis resistance have been discussed based upon previous research and the theoretical framework. We argue for the reduced cost of equity to reflect diminished information asymmetry, a larger investor base, improved growth and cash-flow opportunities as well as reduced risk for litigations as aconsequence of a more sustainable business conduct. To the best of our knowledge, no previous study on the topic has been conducted on the Nordic markets. This study fills thus a research gap on the relation between sustainability, risk andequity market valuation and we sincerely hope to have contributed to academia with new approaches.