The impact of COVID-19 on stock prices of different United States economic sectors is examined using event study methodology. Results revealed that the first confirmed case in US on January 21, 2020 was underestimated by investors and did not disturb stock prices significantly. However, the first local transmission case on February 26, 2020 hit the stock market in the post event window. Due to this event, the stock prices of industries in energy, financials, industrials, real estate and utilities sectors declined but observed price increases in health care, information technology and telecom services industries. First “stay at home” order issued by California State in USA on March 19, 2020, a form of lockdown which restricted public gathering, reduced the market value of consumer staples, health care, industrials, real estate and utilities sectors. This order brought positive changes in stock prices of energy, consumer discretionary, financials, information technology and telecom services sectors. Results of the study can help portfolio managers and investors in the process of asset selection and risk minimization during these types of pandemics. On the other hand, these findings can assist policy makers in designing strategies in advance for financial stability as well as minimizing the negative consequences resulting from COVID-19 related potential health crises in future.