COVID-19 was the central trigger of the 2020 global stock-market crash.
As the novel coronavirus spread internationally in early 2020, governments introduced travel restrictions, business closures, quarantines, and other measures that sharply reduced economic activity. Investors rapidly revised expectations for corporate earnings, energy demand, employment, and global growth. Major stock indexes fell into bear-market territory in February and March.
The crash was intensified by an oil-price dispute between Saudi Arabia and Russia, which contributed to a major fall in crude prices. Central banks and governments then introduced large monetary, fiscal, and public-health responses. Stock markets began recovering later in 2020, even while the pandemic continued, because investors anticipated vaccines, policy support, and economic reopening.
COVID-19 is the disease, while SARS-CoV-2 is the virus that causes it. Keeping those terms separate avoids a common terminology error in accounts of the crash.