The S&P 500 entered a bear market in 2020 after falling about 34% in 33 calendar days.
The decline began after investors reassessed the economic effects of the COVID-19 pandemic, including business closures, travel restrictions, supply disruption, and rapidly rising unemployment. From its February 19, 2020 record close to its March 23 low, the S&P 500 fell approximately 34 percent.
The speed of the move was exceptional. The index entered bear-market territory, conventionally defined as a fall of at least 20 percent from a recent closing high, on March 12, 2020. Governments and central banks then introduced enormous fiscal, monetary, and emergency-lending responses. Those measures, together with improving expectations about vaccines and reopening, helped produce a rapid rebound.
The Dow also fell sharply, and the Nasdaq Composite experienced a major decline, so the S&P 500 is not the only valid measure of the episode. It is used here because its 34-percent peak-to-trough statistic is widely cited and represents a broad large-company U.S. benchmark.