Stock futures were introduced to hedge positions in the market, so that one can safeguard her portfolio in the event of an unpredictable outcome. However, the cost involve in creating futures positions is very high, as it requires margins, which is in turn decided by the volatility of the underlying. So there is another tool available in the market, called option, which can be considered an insurance against such unpredictable outcome. Options are contracts that give the right but not the obligation to buy or sell an asset. Investors typically use derivatives for three reasons — to hedge a position, to increase leverage, or to speculate on an asset's movement.