Which global health emergency triggered the rapid 2020 stock-market crash?

The COVID-19 pandemic triggered the rapid 2020 stock-market crash.

As the virus spread internationally in early 2020, governments imposed travel restrictions, business closures, and other measures that sharply reduced economic activity. Investors also feared disruptions to supply chains, corporate earnings, employment, and energy demand. Equity markets fell rapidly during February and March.

The S&P 500 entered a bear market on March 12, 2020, after reaching its previous record close on February 19. On March 16, the index fell 12%, its largest one-day percentage decline since 1987. Major central banks and governments then introduced extensive monetary, fiscal, and financial-support measures.

The crash was not caused only by public-health news. A disagreement between Russia and Saudi Arabia over oil production added pressure in March, while leveraged positions and forced selling amplified market moves. Markets recovered unusually quickly compared with many earlier crashes, although the economic and human effects of the pandemic were much longer lasting.