Cash Settlement Contracts
To settle a futures contract where the underlying asset is a financial instrument, such as a stock index or interest rate rather than a physical commodity, you deliver cash.
In contrast, when you settle a futures contract on other commodities, you deliver the physical product. But because index values or interest rates are intangible, physical delivery is not possible.
The way you calculate the amount due is defined in the contract. When the underlying instrument is an index, this usually involves multiplying the value of the index times a fixed amount. For example, the cash settlement of a contract on the Standard & Poor's MidCap 400 Index is determined by multiplying the value of the index times $500.
However, in the vast majority of cases, futures contracts are offset before the settlement date, and no delivery is required.