The spot price difference of stock index futures refers to the difference between the stock index futures price and the actual spot index price. Stock index futures is a derivative, and the difference between its price and the actual spot index is normal, so the difference between futures and spot has always existed. The current difference reflects the confidence and mood fluctuation of the market. In the futures market, the greater the difference between futures and spot, the greater the uncertainty of investors on the market trend, and the investment risk may increase.

Judging from the current difference, the price forecasting ability of stock index futures is relatively strong. The change of stock index futures price is often later than that of spot index price. In the case of unbalanced supply and demand in the market, the change of stock index futures price is lagging behind, and it may take some time to be reflected in the stock index futures price. Therefore, observing the change of the current spread can provide investors with trading signals and help them to predict the market trend more accurately and formulate effective investment strategies.

In stock index futures trading, the price difference between futures index and futures index may also be affected by other factors. For example, policy changes, macroeconomic situation, market liquidity and other factors will have an impact on the current difference. In addition, the stock index futures trading itself will also have an impact on the current difference. For example, when a large number of transactions occur in futures trading, the futures price may be changed, which may lead to the change of the current difference. Therefore, when trading stock index futures, investors should always pay attention to the change of the current difference and adjust their investment strategies accordingly to reduce the trading risk.