Specifically, when the fair value is up/down in the preopening market hours, the stock market is expected to open higher/ lower. When the spread is at fair value, obviously there is no incentive for...

Specifically, when the fair value is up/down in the preopening market hours, the stock market is expected to open higher/ lower. When the spread is at fair value, obviously there is no incentive for professional traders to own the futures or the cash index.