The price index is a percentage obtained by comparing the average stock price in subsequent periods with the base period price of stock investment. An index reflecting the change of stock price level. If the price of a stock rises by 10% on a certain day compared with the benchmark date, then the stock price index of that day is 1 10.
Because a large number of enterprises issue stocks and thousands of listed stocks, a certain number of stocks represent different types of enterprises, and the stock price index is prepared to fully reflect the changing trend of stock prices. The more important stock price indexes in the world include Dow Jones Stock Average Price Index, Poole Stock Average Price Index, Hang Seng Stock Average Price Index, Financial Times Stock Average Price Index and Tokyo Stock Exchange Stock Price Index.
1. The price index is divided into: single index, which reflects the rise and fall of a commodity price level; Category index, that is, classified commodity price index, reflects the rise and fall of a certain commodity price level; Comprehensive index, which reflects the rise and fall of the overall level of commodity prices. According to the difference of the base period used in its calculation, it can be divided into monthly price index (pre-basic period), year-on-year price index (the same period one year before the basic period) and fixed base price index (the basic period with fixed term).
2. Arithmetic average method. Is to calculate the arithmetic average of all the constituent samples in the stock index. Weighted average method. Is to calculate the weighted average of all the constituent samples in the stock index. Usually, the weight is allocated according to the total market value or the total number of listed shares of each stock at that time. The stock index of most countries in the world is calculated by the weighted average method, such as American Standard & Poor's Index, Paris Stock Exchange Index, Commerzbank Index, Italian Commercial Bank Index, Toronto 300 Index and Tokyo Stock Exchange Index.
3. Cardinal correction method. The purpose of the bill is to change the number of listed shares and the total share price due to paid capital increase, listing of new shares or cancellation of listing. In order to make the recording period basically consistent with the counting caliber of the base period, the stock price of the base period must be adjusted accordingly. The method is to calculate the ratio of the total price of the current period before and after the number of listed stocks changes, and multiply the total stock price of the original base period by this ratio to get the base period correction value.