The Stock Market Crash of 1987 was a dramatic one-day plunge in the Dow Jones Industrial Average, with the index dropping more than 20% in a single day. This crash, which took place on October 19th, 1987, is also known as Black Monday. It was the largest single-day decline in the Dow's history, and it sent shockwaves throughout the financial world.
While no single factor contributed to the Dow's largest daily decline, the crash was primarily caused by a combination of overvaluation in the Stock market, an increase in program trading, and a lack of liquidity in the market. This combination of factors created a perfect storm that sent the market spiraling downward.
In the aftermath of the crash, the Securities and Exchange Commission (SEC) took action to reduce the amount of program trading in the market. It also made it illegal for a single investor to own more than 5% of the shares of a particular Stock. In addition, the SEC approved the dismissal of lawsuits challenging the prudence of employee Stock ownership plan (ESOP) offerings in defined contribution (DC) plans.