SSE Indices are all calculated using a Paasche weighted composite price index formula. This means that the index is based on a base period on a specific base day for its calculation. The base day for SSE Composite Index is December 19, 1990, and the base period is the total market capitalization of all stocks of that day. The Base Value is 100. The index was launched on July 15, 1991.
The formula is:
Current index = Current total market cap of constituents × Base Value / Base Period
Total market capitalization = ∑ (price × shares issued)
The B share stocks are generally denominated in US dollars for calculation purposes. For calculation of other indices, B share stock prices are converted to RMB at the applicable exchange rate (the middle price of US dollar on the last trading day of each week) at China Foreign Exchange Trading Center and then published by the exchange.