Which global health emergency was associated with the 2020 stock-market crash?

The 2020 stock-market crash was associated with the COVID-19 pandemic.

As COVID-19 spread internationally in early 2020, governments introduced travel restrictions, lockdowns, business closures, and other measures that sharply reduced economic activity. Investors feared falling company revenues, disrupted supply chains, unemployment, and a worldwide recession. Oil-market tensions added another shock in March.

The S&P 500 entered a bear market on March 12, 2020, and reached a short-term low on March 23. The speed of the decline was extraordinary, but markets later rebounded rapidly as central banks cut rates, governments provided fiscal support, and investors anticipated vaccines and economic reopening.

The crash is sometimes described simply as a pandemic crash, but it had several interacting causes. COVID-19 was the central trigger, while financial-market structure, policy responses, and uncertainty shaped the size and duration of the fall. The episode also produced repeated exchange circuit-breaker halts in the United States.