Stock market crash

A stock market crash is a sudden dramatic decline of stock prices across a significant cross-section of a stock market, resulting in a significant loss of paper wealth. Crashes are driven by panic as much as by underlying economic factors. They often follow speculative stock market bubbles.

Stock market crashes are social phenomena where external economic events combine with crowd behavior and psychology in a positive feedback loop where selling by some market participants drives more market participants to sell. Generally speaking, crashes usually occur under the following conditions^[1]: a prolonged period of rising stock prices and excessive economic optimism, a market where P/E ratios exceed long-term averages, and extensive use of margin debt and leverage by market participants.

There is no numerically specific definition of a stock market crash but the term commonly applies to steep double-digit percentage losses in a stock market index over a period of several days.

1929 - The stock market crash: 

Causes of the Stock Market Crash

The 1920’s were a time of unbelievable prosperity. The stock market was going through the roof and the United States seemed to have the formula for limitless prosperity. However, the same formula that generated all of that profit would also be the cause of Black Tuesday.

Investment during the 1920’s was based on the unstable basis of margin buying. Investors bought borrowed money from their brokers, who went to banks for that money. When stocks failed and investors needed to default, the money was permenantly lost.

However, adding to the crash of ‘29 was the slowing economy. The desire for consumer durables (expensive items refrigerators, radios, and automobiles) went down as Americans became satisfied with what they had. This in turn affected the companies and workers that produced these items. A downward spiral was set in motion.

What made the stock market crash? Here’s a brief summary.

Capital is the tools needed to produce things of value out of raw materials. Buildings and machines are common examples of capital. A factory is a building with machines for making valued goods. Throughout the twentieth century, most of the capital in the United States was represented by stocks. A corporation owned capital. Ownership of the corporation in turn took the form of shares of stock. Each share of stock represented a proportionate share of the corporation. The stocks were bought and sold on stock exchanges, of which the most important was the New York Stock Exchange located on Wall Street in Manhattan. 

Throughout the 1920s a long boom took stock prices to peaks never before seen. From 1920 to 1929 stocks more than quadrupled in value. Many investors became convinced that stocks were a sure thing and borrowed heavily to invest more money in the market. 

But in 1929, the bubble burst and stocks started down an even more precipitous cliff. In 1932 and 1933, they hit bottom, down about 80% from their highs in the late 1920s. This had sharp effects on the economy. Demand for goods declined because people felt poor because of their losses in the stock market. New investment could not be financed through the sale of stock, because no one would buy the new stock. 

But perhaps the most important effect was chaos in the banking system as banks tried to collect on loans made to stockmarket investors whose holdings were now worth little or nothing at all. Worse, many banks had themselves invested depositors’ money in the stockmarket. When word spread that banks’ assets contained huge uncollectable loans and almost worthless stock certificates, depositors rushed to withdraw their savings. Unable to raise fresh funds from the Federal Reserve System, banks began failing by the hundreds in 1932 and 1933. 

By the inauguration of Franklin D. Roosevelt as president in March 1933, the banking system of the United States had largely ceased to function. Depositors had seen $140 billion disappear when their banks failed. Businesses could not get credit for inventory. Checks could not be used for payments because no one knew which checks were worthless and which were sound. 

Roosevelt closed all the banks in the United States for three days - a “bank holiday.” Some banks were then cautiously re-opened with strict limits on withdrawals. Eventually, confidence returned to the system and banks were able to perform their economic function again. To prevent similar disasters, the federal government set up the Federal Deposit Insurance Corporation, which eliminated the rationale for bank “runs” - to get one’s money before the bank “runs out.” Backed by the FDIC, the bank could fail and go out of business, but then the government would reimburse depositors. Another crucial mechanism insulated commercial banks from stock market panics by banning banks from investing depositors’ money in stocks.