The S&P 500 entered a bear market in 16 trading days during the COVID-19 stock-market crash of 2020.
The index fell from its record close on February 19, 2020, to a bear-market decline of at least 20% on March 12. That made the move into bear-market territory the fastest such transition in the S&P 500's history at the time.
The crash reflected mounting concern about the coronavirus pandemic, business closures, travel restrictions, supply disruptions, and the economic consequences of efforts to slow transmission. An oil-price dispute between Saudi Arabia and Russia added pressure during the sell-off.
The Federal Reserve cut interest rates and introduced emergency lending measures, while governments enacted fiscal support. The S&P 500 reached its 2020 closing low on March 23 before recovering rapidly. The speed of both the fall and rebound made the episode distinct from slower historical crashes.