What was the fastest U.S. bear market on record when the S&P 500 fell 20% in 2020?

The COVID-19 bear market was the fastest U.S. bear market when the S&P 500 fell 20% in 2020.

The S&P 500 entered bear-market territory on March 12, 2020, after the spread of COVID-19 triggered extraordinary uncertainty about public health, economic activity, and corporate earnings. From its February 19 record close to its March 23 low, the index fell about 34%.

The decline was unusually rapid: the index moved from a record high to a 20% loss in only 16 trading days. Travel restrictions, business closures, an oil-price shock, and forced liquidation all intensified the turmoil. Trading halts, known as circuit breakers, were triggered several times.

Central banks and governments responded with emergency interest-rate cuts, asset purchases, fiscal support, and lending programs. Markets then recovered sharply, although the economic effects and sector-level damage were uneven. The crash is sometimes confused with the 2020 recession itself; the bear market describes the stock-price decline, not the full economic episode.