This research study examines the risk-adjusted performance and portfolio risk of 60 large cap equity funds - mutual funds - under Swedish management. These funds apply environmental, social and governance criteria in their investment strategies. The empirical context concerns the COVID-19 situation and the context is divided into three periods, before, during and after the COVID-19 crisis. The ESG concept, modern portfolio and stakeholder theories are used to develop a theoretical base for the study on which the hypotheses are based which are summarized in a conceptual model. Secondary data regarding ESG and risk-adjusted returns are collected for each fund based on which the sharpe ratios and standard deviations (total or portfolio risk) for each fund are calculated. While there are associations between ESG and portfolio risk, no associations are found between ESG and sharpe ratios. As a result, this confirms the fact that ESG could be characterized as a mechanism to protect against downside risk in poor economic times but no association was established that ESG could also be used as a mechanism to determine efficiency in terms of risk-adjusted performance