The S&P 500 lost almost 34% during the COVID-19 crash from February to March 2020.
The index reached a record closing high on February 19, 2020, before falling rapidly as the coronavirus spread worldwide. It reached a bear-market low on March 23, 2020, representing a decline of about 34% from the February peak.
The sell-off reflected uncertainty about public health, business closures, travel restrictions, employment, and the economic outlook. Extraordinary monetary and fiscal measures, along with hopes for vaccines and reopening, later helped drive a powerful rebound.
The Dow also suffered large point and percentage losses, while the Nasdaq Composite eventually proved more resilient because of its concentration in major technology companies. The S&P 500 is the clearest broad-market reference because it represents 500 leading U.S. companies rather than a single sector.