the DowJonesIndustrialAverage (DJIA) is a stock market index, which was founded in 1884 by CharlesDow and EdwinJones, founders of The Wall Street Journal and Dow Jones Company. The Dow Jones index is considered as one of the important indicators of the performance of the American stock market, which measures the stock performance of the 31 largest and most famous listed companies in the United States.

The compilation method of Dow Jones index has undergone many adjustments. Initially, it had only 12 constituent stocks, mainly composed of industrial companies, so it was called "Dow Jones Industrial Average". In 1929, the Dow Jones index added 21 industrial companies and 15 railway companies, making it more diversified. Today, the Dow Jones index contains the stocks of 31 large companies, covering many industries, including technology, finance, consumer goods, health care, industry and energy.

the Dow Jones index is calculated by adding up the stock prices of all constituent stocks and then dividing by a fixed divisor. This divisor will be adjusted periodically to maintain the continuity of the index. The rise and fall of the Dow Jones index reflects investors' confidence in the US stock market and the overall economic situation. When the index rises, it is usually regarded as a bull market, indicating that investors have confidence in the economy and corporate profits; When the index falls, it is regarded as a bear market, indicating that investors are worried about the economy and corporate profits.

The Dow Jones index has a high influence in the financial market, and global investors, policy makers and the media will pay close attention to its trend. The performance of the Dow Jones index not only reflects the health of the American economy, but also has a certain impact on the global stock market. Therefore, the Dow Jones index is widely regarded as one of the important indicators of the global financial market.