The CSI 300 is a stock market index that represents the performance of the top 300 companies listed on the Shanghai Stock Exchange and the Shenzhen Stock Exchange in China. It is widely used as a benchmark for the overall performance of the Chinese equity market and includes companies from various sectors, such as finance, technology, and consumer goods. Launched in 2005, the CSI 300 is calculated based on the market capitalization of its constituent stocks, reflecting their total market value. Investors and analysts often use this index to gauge market trends and make informed investment decisions in the rapidly growing Chinese economy.