Stock index futures is a financial tool that can be used for speculation and hedging, and its price is related to a specific stock index. Holding stock index futures requires a certain cost, which is called holding cost. The holding cost is paid as part of the margin when trading, and its size depends on the leverage ratio chosen by investors. The higher the leverage ratio, the higher the holding cost.

Another factor in the holding cost of stock index futures is interest rate. The longer it is held, the higher the interest rate investors need to pay. This is because futures trading generally adopts leverage mode, and you only need to pay the deposit when buying, and you don't need to pay the full contract value. Investors need to pay a certain amount of interest to the futures company to make up for the capital cost paid by the company for him. Therefore, the longer the holding period, the higher the interest that investors need to pay.

Holding stock index futures also needs to consider handling fees. In addition to margin and interest, investors also need to pay a handling fee for each transaction. The handling fee is usually a fixed proportion of the contract value, and different futures companies charge different fees. Although the handling fee is much lower than the margin and interest, investors also need to consider the cost of handling fee, because it will affect the calculation of investment return. Therefore, when trading stock index futures, investors need to comprehensively consider all the cost factors and choose the best trading strategy.