The Dow Jones Industrial Average (DJIA), sometimes referred to as the Dow or Dow 30, is a stock market index that tracks the performance of 30 large, publicly traded companies in the United States. Created in 1896, it is the oldest continuous barometer of the U.S. stock market, and one of the most widely quoted indicators of the stock market’s overall health. The DJIA takes the weighted average of the stock prices of the 30 component companies.