How Do Puts & Calls Work in the Stock Market?

The options market allows traders to speculate on the direction of stock prices or to hedge investments they already own. Before having a go at the volatile options market, educate yourself on how it works and about the two basic flavors of option contracts: puts and calls.

Call Options

A call option is a contract to buy a stock at a set price, and within a limited time. The contract sets a strike price at which you can buy the stock. The contract ends when its expiration date passes. A stock option represents 100 shares of the underlying stock, and the expiration date is the third Friday of the expiration month. For example, a Microsoft March 2013 25 call option gives you the right to buy 100 shares of Microsoft at $25 per share until the close of business on the third Friday of March 2013. If the option is quoted at $2, then you must put down $200 to buy the contract, in addition to transaction fees.

Option Prices

Calls have intrinsic value if the stock is trading above the strike price. A Microsoft 25 call, for example, has $5 of intrinsic value if the stock itself is at $30. If the stock goes to $35, the option doubles its intrinsic value to $10. Options also have time value. The longer until expiration, the more time value they have. At expiration, the time value is zero and the option either has intrinsic value or is worthless. The volatility of the underlying stock also adds value, as does an active market in which traders are busily buying and selling a high volume of options.

Put Options

A put is a contract to sell a stock or "put" it to a buyer. It also represents 100 shares, and it has the same intrinsic value as a call -- in reverse. The lower a stock moves, the higher its put options rise. You can buy one or 100 calls or puts at a time. You also can short (sell) the options, or create combinations that return a profit if the stock fails to move or if it stays within a narrow price band. Options require much less capital than buying stock outright, and they can return a much greater profit. But the price volatility and looming expiration make them far riskier than stock shares.

Index Options and Settlement

Calls and puts are available on a wide variety of underlying investments. In addition to individual stocks, you can trade puts and calls on market indexes such as the Dow Jones industrials or the Standard & Poor's 500. You can also trade options on futures contracts for commodities such as oil, gold or copper. When you deal in options, you can trade them to close your position, you can exercise them to buy or sell the underlying stock, or you can hold them until expiration. At that point your position in a worthless option disappears, or your broker settles the contract for you if it still has value.