Refers to the mode of futures: you can buy up or down, which is a two-way transaction, and you can make money by buying up and down.

A-share main board is a unilateral market, and only by buying up can we make money. In addition, stock index futures will affect the rise and fall of A-shares, so the main forces and institutions usually have asset allocation on stock index futures to cooperate with their operation on the main board of A-shares. The threshold of stock index futures is still a little high for ordinary retail investors, so they cannot participate.

Stock market index is a reference index compiled by stock exchanges or financial services institutions to reflect changes in the stock market. Based on this, investors can test the effect of their investment and predict the trend of the stock market. At the same time, the press, company bosses and even political leaders also use this as a reference index to observe and predict the social, political and economic development situation.

Due to the complexity and variety of stock index calculation, people often select several 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.

There are three factors to be considered in calculating the stock index: 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.

When calculating the average or index of stock prices, the following four points are usually considered:

Sample stocks must be typical and ordinary. Therefore, when selecting sample correspondence, we should comprehensively consider the factors such as industry distribution, market influence, stock grade, and appropriate quantity.

The calculation method should have strong adaptability, and can make corresponding adjustments or corrections to the ever-changing stock market, so that the stock index or average value has better sensitivity.

There should be scientific calculation basis and means. The calculation basis must be unified, generally based on the closing price, but with the increase of calculation frequency, some are calculated at the hourly price or even shorter time.

The base period should be balanced and representative.