Put options give the holder the right to sell an underlying asset at a specified price. A put option is bought if the trader expects the price of the underlying to fall within a certain time frame. Buy a call option or sell a put option only when you expect the market to go up. Buy a put option or sell a call option only when you expect the market to go down. Call options are those contracts that give the buyer the right, but not the obligation to buy the underlying shares or index in the futures. They are exactly opposite of Put options, which give you the right to sell in the future.