During the 2020 stock-market crash, the disease that caused the global economic shock was COVID-19.
The crash unfolded as the novel coronavirus spread internationally, prompting travel restrictions, business closures, quarantines, and other measures that sharply reduced economic activity. Financial markets reacted rapidly to uncertainty about corporate earnings, supply chains, employment, and the scale of the public-health emergency.
The World Health Organization characterized COVID-19 as a pandemic on March 11, 2020. U.S. stocks then entered a bear market at exceptional speed. The S&P 500 fell about 33.9% from its February 19 peak to its March 23 low, before recovering as governments and central banks introduced major fiscal and monetary support.
COVID-19 was the disease caused by the virus SARS-CoV-2. The terms are often confused: SARS-CoV-2 names the virus, while COVID-19 names the disease. The market crash also reflected an oil-price shock and broader financial stress, not the health crisis alone.