Stock index futures are a kind of futures, which can be roughly divided into two categories, commodity futures and financial futures. The main varieties of financial futures can be divided into foreign exchange futures, interest rate futures, stock index futures and treasury bonds futures. Stock index futures are futures contracts with stock index as the subject matter. After a certain period of time, the two parties trade the price level of the stock index and make delivery by cash settlement of the price difference. The full name of stock index futures is stock index futures, which can also be called stock index futures and futures index. Stock index futures are different from stock trading. Compared with stocks, stock index futures have several distinct characteristics, which are particularly important for stock investors:

(1) Futures contracts have an expiration date and cannot be held indefinitely. After buying a stock, you can always hold it. Under normal circumstances, the number of shares will not decrease. However, stock index futures have a fixed expiration date and will be delisted when it expires. Therefore, trading stock index futures cannot be equated with buying and selling stocks. After trading, we must pay attention to the expiration date of the contract to decide whether to close the position in advance or wait for the expiration of the contract (fortunately, the stock index futures are settled in cash and do not need to actually deliver the stock), or to transfer the position to next month.

(2) Futures contracts are margin transactions and must be settled every day. Stock index futures contracts are margin transactions. Generally, you can buy and sell a contract by paying about 10- 15% of the contract face value, which improves the profit space, but on the other hand, it also brings risks, and you must settle the profit and loss every day. After buying a stock, the book profit and loss are not settled before selling. However, stock index futures are different. After the transaction, the contract held in hand should be settled at the settlement price every day, and the book profit can be withdrawn, but the book loss (that is, additional margin) must be made up before the opening of the next day. And because it is a margin transaction, the loss may even exceed your investment principal, which is different from stock trading.

(3) Futures contracts can be sold short, and stock index futures contracts can be sold short very conveniently, and then bought back after the price drops. It is ok to short stocks, but it is relatively difficult. Of course, once the price rises instead of falling after short selling, investors will face losses.

(4) The liquidity of the market is relatively high. Studies have shown that the liquidity of stock index futures market is obviously higher than that of stock spot market. For example, 199 1, the trading volume of FTSE-100 index futures has reached 85 billion pounds.