The prices of stock index futures are mainly determined by stock indices, which are subject to many factors. So the price trend of the stock index futures is also subject to these factors. The factors include:
(1) macroeconomic data, such as GDP, industrial index, inflation rate, etc.;
(2) macroeconomic policies, such as interest rate raising, exchange rate reform, etc.;
(3) various information related to the enterprises whose stocks are selected as constituents of indexes, such as listing, additional shares issuance, and interest payment and dividend distribution of heavyweight constituent stocks, etc.;
(4) international financial market trend, such as the price change of Dow Jones Index of the NYSE, the price change of the international crude oil futures market, etc.
Besides, unlike the stock indices, the stock index futures have expiration dates. So the prices of stock index futures will also be influenced by the length of the time to the expiration day.