The CSI 100 Index is a capitalization-weighted, free float adjusted stock market index designed to replicate the performance of top 100 stocks traded in the Shanghai and Shenzhen stock exchanges. It is a sub-index of CSI 300 Index. The index is compiled by the China Securities Index. Its value is normalized relative to a base of 1000 on 30 December 2005. CSI 100 Index was considered as an index for big caps. Wikipedia