The Dow just tumbled into a bear market — here’s how long those downturns last on average

It’s the end of a bullish era for the stock market and the beginning of a new phase of bearishness, after a sharp plunge for risk assets on Wednesday pushed the Dow Jones Industrial Average into bear-market territory for the first time in more than a decade.

U.S. equity indexes on Wednesday mostly resumed a downtrend that saw all three major U.S. equity gauges touch bear-market territory, commonly defined as a decline of at least 20% from a recent peak. The declines deepened after the World Health Organization declared COVID-19,...