This study analyzed the impact of COVID-19, which, in 2020, globally increased uncertainty about the stock repurchase of South Korean listed companies. The results suggest that the market reaction to stock repurchases during the COVID-19 period was significantly subdued. In particular, the market reaction to KOSPI companies, on stock repurchase, was positive, while it was negative in the case of KOSDAQ companies. It has also been reported that the market ranks lower on the reliability of the signal after the onset of COVID-19. This means that if a company discloses a stock repurchase in a situation where the value of the market as a whole has declined, it cannot be accepted as an undervalued signal. Furthermore, it was revealed that the market responded more positively to the announcement of repurchases by companies that had actively managed shareholder wealth by repeatedly making stock repurchases before COVID-19. These results suggest that companies should always be aware of this, as the market response to stock repurchases in market shockers such as COVID-19 is weaker. Additionally, managers can manage their stock prices more effectively through stock repurchases during market shockers if they consistently manage their stock prices through stock repurchases when companies are undervalued.