The Wall Street crash of 1929, also known as the Great Crash, was a major stock market crash in the United States which began in October 1929 with a sharp decline in prices on the New York Stock Exchange (NYSE). It triggered a rapid erosion of confidence in the U.S. banking system and marked the beginning of the worldwide Great Depression that lasted until 1939, making it the most devastating crash in the country's history. It is most associated with October 24, 1929, known as "Black Thursday", when a record 12.9 million shares were traded on the exchange, and October 29, 1929, or "Black Tuesday", when some 16.4 million shares were traded.
The "Roaring Twenties" of the previous decade had been a time of industrial expansion in the U.S., and much of the profit had been invested in speculation, including in stocks. Many members of the public, disappointed by the low interest rates offered on their bank deposits, committed their relatively small sums to stockbrokers. By 1929, the U.S. economy was showing signs of trouble; the agricultural sector was depressed due to overproduction and falling prices, forcing many farmers into debt, and consumer goods manufacturers also had unsellable output due to low wages and thus low purchasing power. Factory owners cut production and fired staff, reducing demand even further. Despite these trends, investors continued to buy shares in areas of the economy where output was declining and unemployment was increasing, so the purchase price of stocks greatly exceeded their real value.