when the strike price on the call is less than the market price on the exercise date the holder of the option can use their call option to buy the instrument at the lower strike price if the market price is less than the strike price the call expires unused and worthless a call option can also be sold before the maturity date if it has intrinsic value based on the market s movements 
the put option is effectively the opposite of a call option the put owner holds the right but not the obligation to sell an underlying instrument at the given strike price and period derivatives traders often combine calls and put to increase decrease or otherwise manage the amount of risk that they take example of a call optionsuppose a trader buys a call option with a premium of 2 for apple s shares at a strike price of 100 the option is set to expire a month later the call option gives her the right but not the obligation to purchase the cupertino company s shares which are trading at 120 when the option was written for 100 a month later the option will expire worthless if apple s shares are changing hands for less than 100 a month later but a price point above 100 will give the option buyer a chance to buy shares of the company for a price cheaper than the market price call option faqscall options are a type of derivative contract that gives the holder the right but not the obligation to purchase a specified number of shares at a predetermined price known as the strike price of the option if the market price of the stock rises above the option s strike price the option holder can exercise their option buying at the strike price and selling at the higher market price in order to lock in a profit on the other hand options only last for a limited period of time if the market price does not rise above the strike price during that period the options expire worthless investors will consider buying call options if they are optimistic or bullish about the prospects of its underlying shares for these investors call options might provide a more attractive way to speculate on the prospects of a company because of the leverage that they provide for an investor who is confident that a company s shares will rise buying shares indirectly through call options can be an attractive way to increase their purchasing power puts are the counterparts to calls giving the holder the right to sell and not buy the underlying security at a specific price at or before expiration options are frequently traded on exchanges if you own an option you can sell it to close out the position or you can sell known as writing a call to take a short position in the market if you already own the underlying security you can write a covered call to enhance returns expiring in the money itm simply means that at its expiration its strike price is lower than the market price this means that the holder of the option has the right to buy shares lower than where they are trading for an immediate profit the process of converting the contract into those shares at that price is called exercising note that a call that expires with a strike higher than the market price will be out of the money otm and expire worthless since who would want to purchase shares for higher than you can get in the open market call auctionsin a call auction the exchange sets a specific timeframe in which to trade a stock auctions are most common on smaller exchanges with the offering of a limited number of stocks all securities can be called for trade simultaneously or they could trade sequentially buyers of a stock will stipulate their maximum acceptable price and sellers will designate their minimum acceptable price all interested traders must be present at the same time at the termination of the auction call period the security is illiquid until its next call governments will sometimes employ call auctions when they sell treasury notes bills and bonds it is important to remember that orders in a call auction are priced orders meaning that participants specify the price they are willing to pay beforehand the participants in an auction cannot limit the extent of their losses or gains because their orders are satisfied at the price arrived at during the auction call auctions are usually more liquid than continuous trading markets while continuous trading markets give participants more flexibility example of a call auctionsuppose a stock abc s price is to be determined using a call auction there are three buyers for the stock x y and z x has placed an order to buy 10 000 abc shares for 10 while y and z have placed orders for 5 000 shares and 2 500 shares at 8 and 12 respectively since x has the maximum number of orders she will win the bid and the stock will be sold for 10 at the exchange y and z will also pay the same price as x a similar process can be used to determine the selling price of a stock 