To calculate the stock index, we should consider three factors:
First, sampling, that is, extracting a few representative constituent stocks from many stocks;
The second is weighted, weighted average by unit price or total value, or unweighted average;
The third is a calculation program, which calculates arithmetic average, geometric average, or considers price and total value.
Because there are many kinds of listed stocks, it is an arduous and complicated task to calculate the average price or index of all listed stocks, so people often choose a few representative sample stocks from listed stocks and calculate the average price or index of these sample stocks. Used to indicate the general trend and fluctuation range of stock prices in the whole market.
The extended data "Shanghai Composite Index" is compiled by Shanghai Stock Exchange, with all stocks listed on the Shanghai Stock Exchange as the calculation range and circulation as the weight. The Shanghai Composite Index reflects the general trend of the Shanghai Stock Exchange market.
The Shanghai Composite Index was originally compiled by Jing 'an Securities Business Department of China Industrial and Commercial Bank of China Shanghai Branch Trust and Investment Company according to the actual situation of Shanghai stock market and referring to the generation methods of foreign stock price indicators, and was released publicly on July 199 15.
In February 1992, 2 1, Shanghai A-share index and Shanghai B-share index were added, and in June 1 0993, Shanghai sub-index was added, namely industrial index, business index, real estate index, public utility index and comprehensive industry index, to reflect the respective trends of stocks in different industries.
References:
Baidu Encyclopedia-Shanghai Composite Index