The so-called holding cost refers to the net cost that investors must pay from holding spot assets to the expiration date of futures contracts, that is, the financing cost paid by financing the purchase of spot assets MINUS the income from holding spot assets. F stands for the theoretical price of stock index futures, S stands for the market price of spot assets, R stands for the annual interest rate of financing, Y stands for the annual rate of return from holding spot assets, and△ T stands for the number of days before the contract expires. In the case of simple interest, the theoretical price of stock index futures can be expressed as:

F=S*[ 1+(r-y)*△t /360]

Give examples. Assuming that the current Shanghai and Shenzhen 300 stock index is 1800 points, the one-year financing interest rate is 5%, and the annual return rate of holding the spot is 2%, and a stock index futures contract with the Shanghai and Shenzhen 300 index as the subject matter is 90 days from the expiration date, then the theoretical price of the contract is:1800 * [1+(5