The 沪深300 is a stock market index that represents the top 300 companies listed on the Shanghai Stock Exchange and the Shenzhen Stock Exchange. It is designed to reflect the overall performance of the Chinese stock market and includes large-cap stocks from various sectors, making it a key indicator for investors. Launched in 2005, the 沪深300 is widely used by fund managers and investors to benchmark their investment performance. The index is calculated based on the market capitalization of its constituent stocks, providing a comprehensive view of the market's health and trends in the Chinese economy.