1, Dow Jones Index
The Dow Jones Index is the oldest, most influential and most widely used stock index in the world. It is based on a representative portion of the stocks of companies listed on the New York Stock Exchange, and is generally referred to as the Dow Jones Industrial Average (DJIA), or "Dow" for short. It consists of 30 well-known industrial companies' stocks, which can roughly reflect the price level of the entire industrial stocks in the United States. The Dow is one of the most sensitive stock price averages in the US stock market, and is the main reference for observing market dynamics and investing in stocks. The Dow Jones Index is compiled and published by Dow Jones & Company, an American newspaper group, and is published in its subsidiary, the Wall Street Journal.

2, Standard & Poor's 500 Index
The S&P 500 is a stock index of 500 publicly traded companies in the United States. All companies covered by the S&P 500 are listed on the major US exchanges. Compared to the Dow Jones, the S&P 500 includes more companies and is therefore more diversified in terms of risk, reflecting a wider range of market changes. Because the S&P Index accounts for almost 80% of the total value of NYSE stocks and takes into account factors such as market capitalisation, liquidity and industry representation in stock selection, it is an important reference for measuring operational performance.

3, Nasdaq Index
The Nasdaq Composite Index is an average index of stock prices reflecting changes in the Nasdaq stock market. The Nasdaq is a more comprehensive index than the S&P 500 and the Dow, as it consists of hundreds of the fastest growing advanced technology, telecommunications and biotechnology companies in the United States, including many high-tech companies, and covers all new technology sectors.