1. Dow Jones Industrial Average，DJIA
The Dow Jones Industrial Average was invented by Charles Dow back in 1896, which is the oldest and single most watched index in the world. The DJIA is a price-weighted average of 30 significant stocks traded in United States.
With the current inclusion of only 30 stocks, critics argue that the DJIA is not a very accurate representation of the overall market performance even though it is the most cited and most widely recognized of the stock market indices.

2. S&P500
S&P500 is owned and maintained by Standard & Poor’s, a division of McGraw-Hill. 500 stocks had been chosen based on their market size, liquidity and industry grouping, among other factors. Since the DJIA contains only 30 companies, most people agree that the S&P500 is a better representation of the U.S. market. Therefore, it is one of the most commonly used benchmarks for all over the world.

3. NASDAQ Composite Index
Launched in 1971, the Nasdaq Composite Index measures all domestic and international based common type stocks listed on the Nasdaq Stock Market, which is calculated under a market capitalization weighted methodology.
The Nasdaq Composite Index measures all NASDAQ domestic and international based common type stocks listed on The Nasdaq Stock Market.