The CSI 300 is a capitalization-weighted stock market index designed to replicate the performance of the top 300 stocks traded on the Shanghai Stock Exchange and the Shenzhen Stock Exchange. It has two sub-indexes: the CSI 100 Index and the CSI 200 Index. Over the years, it has been deemed the Chinese counterpart of the S&P 500 index and a better gauge of the Chinese stock market than the more traditional SSE Composite Index. The index is compiled by the China Securities Index Company, Ltd. It has been calculated since April 8, 2005. Its value is normalized relative to a base of 1000 on December 31, 2004. It is considered to be a blue chip index for Mainland China stock exchanges. Wikipedia