Under normal circumstances, the futures index is higher than the stock index, but when it is too high, it will be ordered to return to its normal position by short selling. Of course, the futures index and the stock index are related, and the futures index still reflects everyone's prediction of the future trend of the stock index. Of course, there will be linkage. The closer to delivery, the smaller the difference between futures and cash. Because it can be delivered in cash.

When it is far from the delivery date, it may still be far away.

A negative number means that the futures index is lower than the stock index, and the bears are strong.