Black Tuesday was the last of a series of days in October 1929 during which the United States stock market lost a historic amount of value. This market crash was one of the pivotal events contributing to the Great Depression , a worldwide economic slump of the 1930’s. The use of the name “Black Tuesday” for the day of the crash is a reference to black as a traditional color for mourning, particularly in Western societies.
Background.
During the 1920’s, the United States economy grew rapidly and many Americans became more prosperous. The average price of stocks on the New York Stock Exchange increased about six-fold from 1921 to 1929. Rising share prices encouraged many people to speculate—that is, buy shares in hope of making large profits following future price increases. In 1928 and 1929, the U.S. government raised interest rates in an effort to slow stock market speculation.
Market crash.
On Thursday, Oct. 24, 1929, later known as “Black Thursday,” share prices dropped sharply. Most share prices remained steady on Friday and Saturday. But the following Monday, October 28, share prices fell again and the stock market lost nearly 13 percent of its total value. At the end of the day, the Dow Jones Industrial Average was 260.64. The Dow Jones Industrial Average, which tracks stock prices of 30 major firms, shows the price trends of stocks traded in the United States. 
On Tuesday, Oct. 29, 1929, shareholders panicked. They sold a record 16,410,030 shares. At one time, the stock market average fell to a low of 212.33, but the market rallied back to close the day at 230.07. This loss of nearly 12 percent was one of the worst single-day losses in stock market history.
The following day, October 30, the stock market had one of its largest single-day gains when it gained over 12 percent to close at 258.47. However, share prices fluctuated and fell for the next three years. Because of falling stock prices, banks and investors lost large sums of money. Also, increased uncertainty about the future of the economy led consumers to cut back on purchases of goods and services. These factors helped make the Great Depression worse. By 1932, the stock market average had fallen nearly 90 percent from its 1929 high.
The term “Black Tuesday”
can also refer to Tuesday, Feb. 7, 1967, when more than 100 bushfires were burning across the Australian state of Tasmania . Some 62 people died in the fires.
