Bear markets are quite common. Since 1900, there have been 33 of them, so they occur every 3.6 years on average. Just to name the three most recent notable examples:2000-2002 dot-com crash: Growing use of the internet in the late 1990s led to a massive speculative bubble in technology stocks. While all major indices fell into bear market territory after the bubble burst, the Nasdaq was hit especially hard: By late 2002, it had fallen by about 75% from its previous highs.
2008-2009 financial crisis: Due to a wave of subprime mortgage lending and the subsequent packaging of these loans into investable securities, a financial crisis spread across the globe in 2008. Many banks failed, and massive bailouts were required to prevent the U.S. banking system from collapsing. By its March 2009 lows, the S&P 500 had fallen by more than 50% from its previous highs.
2020 COVID-19 crash: The 2020 bear market was triggered by the COVID-19 pandemic spreading across the world and causing economic shutdowns in most developed countries, including the U.S. Because of the speed at which economic uncertainty spread, the stock market’s plunge into a bear market in early 2020 was the most rapid in history.