Why the price change in future and option differs?
Future price is based on a future delivery date of an instrument. Accordingly a dealer who's selling a future, can hedge his position by buying the underlying equity position. He has to borrow money at the risk free rate in order to do this. So the cost of hedging is generally just the interest rate charged for the period of the future position. On the other hand, an option's pay off is based on the price of the underlying stock. Hence you will see that the underlying price for an option will be different compared to the price of the future. One has to be aware that an option can be based off of a future, in which case both the future, and the option will be pointing to the same instrument for settlement. Although in general the future price should be higher than the spot price, there are cases where it will be lower than the spot. This generally happens due to supply-demand mismatch, and when there's serious issue with the viability of a company. Especially in the Ind...