Imagine that the Dow Jones Industrial Average exploded upward tomorrow and rose more than 550 points.
Sound impossible? Such surges have happened five times during the Dow industrials' 100-year history. The key is to look at the percentage change in the average, which is more important than the point change. A 100-point move today enriches investors no more than a one-point move did in the early 1930s.The table shows the biggest one-day gains, all 10 percent or greater. Most of them came in the early 1930s, when stocks were extraordinarily volatile. Investors' nerves were rubbed raw by the crash of 1929 and by the Depression. Alternating currents of fear and greed pushed the market up and down violently.
The biggest gain ever was 15.34 percent on March 15, 1933, the day after Franklin D. Roosevelt's bank holiday ended. All trading on the New York Stock Exchange had been suspended since March 3.
Laszlo Birinyi, who heads a stock-market information firm in Greenwich, Conn., says the March 1933 advance was helped along when people were given extra time to file their tax returns, reducing their need to sell stocks.
Two of the biggest gains were rebounds following the crashes of 1929 and 1987. That's no surprise, says Tim Hayes, of Ned Davis Research Inc. in Nokomis, Fla. Volatility, he says, is most pronounced near market bottoms.