The dot-com bubble, also known as the dot-com boom, the tech bubble, and the Internet bubble, was a stock market bubble caused by excessive speculation of Internet-related companies in the late 1990s, a period of massive growth in the use and adoption of the Internet.Between 1995 and its peak in March 2000, the Nasdaq Composite stock market index rose 400%, only to fall 78% from its peak by October 2002, giving up all its gains during the bubble. During the dot-com crash, many online shopping companies, such as Pets.com, Webvan, and Boo.com, as well as several communication companies, such as Worldcom, NorthPoint Communications, and Global Crossing, failed and shut down. Some companies that survived, such as Amazon.com, lost large portions of their market capitalization, with Cisco Systems alone losing 80% of its stock value.

The Dow Jones Industrial Average (DJIA), Dow Jones, or simply the Dow (), is a price-weighted measurement stock market index of 30 prominent companies listed on stock exchanges in the United States.

Although the DJIA is one of the oldest and the most commonly followed equity indices, many professionals consider the Dow to be an inadequate representation of the overall U.S. stock market compared to broader market indices such as the S&P 500 or Russell 2000 Index. The DJIA includes only 30 large companies and is a price-weighted index, unlike later stock indices which use market capitalization. Furthermore, the DJIA does not use a weighted arithmetic mean.The value index can also be sum of the stock prices of the companies included in the index, divided by a factor which is currently (as of November 2021) approximately 0.152. The factor is changed whenever a constituent company undergoes a stock split so that the value of the index is unaffected by the stock split.

First calculated on May 26, 1896, the index is the second-oldest among U.S. market indices (after the Dow Jones Transportation Average). It was created by Charles Dow, the editor of The Wall Street Journal and the co-founder of Dow Jones & Company, and named after him and his business associate, statistician Edward Jones. The word industrial in the name of the index initially emphasized the heavy industry sector, but over time stocks from many other types of companies have been added to the DJIA.

The index is maintained by S&P Dow Jones Indices, an entity majority-owned by S&P Global. Its components are selected by a committee. The ten components with the largest dividend yields are commonly referred to as the Dogs of the Dow. As with all stock prices, the prices of the constituent stocks and consequently the value of the index itself are affected by the performance of the respective companies as well as macroeconomic factors.