The COVID-19 pandemic in Korea provides grounds for understanding the effect of corporate social responsibility (CSR) on the stock returns and trading behavior of investors, particularly when most businesses have fallen on hard times. This study empirically finds that CSR reputations are associated with higher returns and lower volatilities by comparing the two portfolios which are composed of CSR and non-CSR firms, respectively. We also discover that public pension funds and other institutional investors have liquidated non-CSR stocks more aggressively than CSR stocks. This indicates that institutional investors consider CSR to transform their stock portfolios into less risky ones.