<P> After the experience of the 1929 crash, stock markets around the world instituted measures to suspend trading in the event of rapid declines, claiming that the measures would prevent such panic sales . However, the one - day crash of Black Monday, October 19, 1987, when the Dow Jones Industrial Average fell 22.6%, was worse in percentage terms than any single day of the 1929 crash (although the combined 25% decline of October 28--29, 1929 was larger than October 19, 1987, and remains the worst two - day decline ever). </P> <P> The American mobilization for World War II at the end of 1941 moved approximately ten million people out of the civilian labor force and into the war . World War II had a dramatic effect on many parts of the economy, and may have hastened the end of the Great Depression in the United States . Government - financed capital spending accounted for only 5 percent of the annual U.S. investment in industrial capital in 1940; by 1943, the government accounted for 67 percent of U.S. capital investment . </P> <P> Together, the 1929 stock market crash and the Great Depression formed the largest financial crisis of the 20th century . The panic of October 1929 has come to serve as a symbol of the economic contraction that gripped the world during the next decade . The falls in share prices on October 24 and 29, 1929 were practically instantaneous in all financial markets, except Japan . </P> <P> The Wall Street Crash had a major impact on the U.S. and world economy, and it has been the source of intense academic debate--historical, economic, and political--from its aftermath until the present day . Some people believed that abuses by utility holding companies contributed to the Wall Street Crash of 1929 and the Depression that followed . Many people blamed the crash on commercial banks that were too eager to put deposits at risk on the stock market . </P>

What caused the stock market to crash in the great depression