The full name of stock index futures (SPIF) is stock index futures, which can also be called stock index futures and futures index. It refers to the standardized futures contract with the stock price index as the subject matter. The two parties agree to buy and sell the underlying index according to the size of the stock price index determined in advance at a future date, and settle the difference in cash after the expiration. As a type of futures trading, stock index futures trading has basically the same characteristics and processes as ordinary commodity futures trading. Stock index futures are a kind of futures, which can be roughly divided into two categories, commodity futures and financial futures.

Stock index futures include two characteristics: one is stock characteristics, and the other is futures characteristics.

From the stock characteristics, the research methods of the two futures are also very different because of the different factors affecting the stock index spot and commodity spot. In order to analyze the trend of commodity futures, investors need to conduct an in-depth investigation on the supply and demand situation that affects the spot trend of commodities. It is very important to choose a good investment platform. For stock index futures, investors need to pay more attention to the macro-economy, industry trends and the trend of heavyweights that have a great influence on the spot trend of stock indexes.

In terms of futures characteristics, the main difference between stock index futures and commodity futures lies in the different settlement methods of maturity. When a commodity futures contract expires, it must be delivered in kind, with one party paying and the other delivering. Due to the particularity of stock index "spot"-stock index, stock index futures introduced by countries all over the world are delivered in cash. The general practice is to take the index-weighted spot price some time before the closing of the last trading day as the settlement price of the open index futures contract.

The main reason is that the price difference is profitable, and only when there is fluctuation can it be profitable. The above four points are only beneficial to market development, so choose D.