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In early 2020, the COVID-19 virus spread rapidly around the world within months. After countries around the world announced the outbreak of COVID-19, many industries suffered a severe recession, but a few industries were able to buck the trend and maintain good performance. The outbreak has driven strong demand for medical products and pharmaceuticals. As the epidemic continues to spread, people are in urgent need of drugs and vaccines to treat COVID-19, which directly promotes the development of the pharmaceutical industry (Alam et al., 2021). This study aims to explore the impact of announcements from the World Health Organization (WHO) or similar official agencies on the development of the epidemic during the COVID-19 epidemic on the stock prices of specific pharmaceutical companies. The study uses event study methodology to analyze the impact of events in the COVID-19 pandemic on these companies. Through an event study on 7 major events during the COVID-19 pandemic, this study found that the stock price changes of different pharmaceutical companies are not uniform. The WHO announcement of a global pandemic and the emergency authorization announcement of drugs have had different significant impacts on different types of pharmaceutical companies. This study provides new information for understanding the stock return change of specific pharmaceutical companies during the COVID-19 epidemic