Glossary

A listed option that you can exercise at any point between the day you purchase it and its expiration date is called an American-style option. All equity options are American style, no matter where the exchange on which they trade is located.

In contrast, you can exercise European-style options only on the last trading day before the expiration date, not before. Index options listed on various US exchanges may be either American- or European-style options.

Buying a call option gives you, as owner, the right to buy a fixed quantity of the underlying product at a specified price, called the strike price, within a specified time period.

For example, you might purchase a call option on 100 shares of a stock if you expect the stock price to increase but prefer not to tie up your investment principal by investing in the stock. If the price of the stock does go up, the call option will increase in value.

You might choose to sell your option at a profit or exercise the option and buy the shares at the strike price. But if the stock price at expiration is less than the strike price, the option will be worthless. The amount you lose, in that case, is the premium you paid to buy the option plus any brokerage fees.

In contrast, you can sell a call option, which is known as writing a call. That gives the buyer the right to buy the underlying investment from you at the strike price before the option expires. If you write a call, you are obliged to sell if the option is exercised and you are assigned to meet the call.

The CBOE, often pronounced "see-bo," is the largest options market in the world. Founded in 1973, the market specializes in trading options contracts on individual equities, indexes, and interest rates.

Over the years, the CBOE has been instrumental in developing a variety of new options-related financial products. One example is the FLEX option, which the CBOE introduced in 1993 to allow investors to add specific provisions to options contracts.

The market is also known for being on the cutting edge of advanced trading technologies, including electronic trading.

When you sell call options on stock that you own, they are covered options. That means if the option holder exercises the option, you can deliver your stock to meet your obligation if you are assigned to complete the transaction.

Similarly, if you sell put options on stock and have enough cash on hand make the required purchase if the option holder exercises, the options are covered. Covered puts are also known as cash-secured puts.

One appeal of selling a covered call is that you collect the premium but don't risk potentially large losses. Otherwise, you may have to buy the stock at a higher market price in order to meet your obligation to deliver stock at the strike price if the option is exercised.

The downside is that if your stock is called away from you, you'll no longer be in a position to profit from any potential dividends or increases in price.

A listed option that you can exercise only on the last trading day before the expiration date is called a European-style option whether it trades on a US exchange, a European exchange, or elsewhere in the world.

For example, many index options listed on various US exchanges are European-style options. In contrast, you can exercise an American-style option at any point between the day you purchase it and its expiration date.

All equity options are American style, no matter where the exchange on which they trade is located.

Corporate executives may be granted incentive stock options (ISOs), also called qualifying stock options. These options aren't taxed when they're granted or exercised, but only when the underlying shares are sold.

If, after exercising the options, participating executives keep the shares for the required period, any earnings from selling the shares are taxed at the owner's long-term capital gains rate.

However, stock option transactions may make sellers vulnerable to the alternative minimum tax (AMT).

Index options are puts and calls on a stock index rather than on an individual stock. They give investors the opportunity to hedge their portfolios or speculate on gains or losses in a segment of the market.

For example, if you own a group of technology stocks but think technology stocks are going to fall, you might buy a put option on a technology index rather than selling short a number of different technology stocks.

If the value of the index does fall, you could exercise the option and collect cash to partially offset a drop in the value of your portfolio.

However, to use this strategy successfully, the index you choose must perform the way the portion of the portfolio you're trying to hedge performs.

And since changes in an index are difficult to predict, index options tend to be volatile. The more time there is until an index option expires, the more volatile the option tends to be.

When you write, or sell, a call option but don't own the underlying instrument, such as a stock in the case of an equity option, the option is described as naked.

Similarly, you write a naked put if you don't have enough cash on hand or in liquid investments to purchase the underlying instrument.

Because you collect a premium when you sell the option, you may make a profit if the underlying instrument performs as you expect, and the option isn't exercised.

The risk you run, however, is that the option holder will exercise the option. In the case of a call, you'll then have to buy the instrument at the market price in order to meet your obligation to sell. Or, if it's a put, you'll have to come up with the cash to purchase the instrument.

If that price of the underlying has moved in the opposite direction from the one you expected, meeting your obligation could result in a substantial net loss. Because of this risk, your brokerage firm may limit your right to write naked options or require that you write them in a margin account.

Buying an option gives you the right to buy or sell a specific financial instrument at a specific price, called the strike price, during a preset period of time.

In the United States, you can buy or sell listed options on individual stocks, stock indexes, futures contracts, currencies, and debt securities.

If you buy an option to buy, which is known as a call, you pay a one-time premium that's a fraction of the cost of buying the underlying instrument.

For example, when a particular stock is trading at $75 a share, you might buy a call option giving you the right to buy 100 shares of that stock at a strike price of $80 a share. If the price goes higher than the strike price, you can exercise the option and buy the stock at the strike price, or sell the option, potentially at a net profit.

If the stock price doesn't go higher than the strike price before the option expires, you don't exercise. Your only cost is the money that you paid for the premium.

Similarly, you may buy a put option, which gives you the right to sell the underlying instrument at the strike price. In this case, you may exercise the option or sell it at a potential profit if the market price drops below the strike price.

In contrast, if you sell a put or call option, you collect a premium and must be prepared to deliver (in the case of a call) or purchase (in the case of a put) the underlying instrument. That will happen if the investor who holds the option decides to exercise it and you're assigned to fulfill the obligation. To neutralize your obligation to fulfill the terms of the contract before an option you sold is exercised, you may choose to buy an offsetting option.

When you buy an option, you pay the seller a nonrefundable amount, known as the option premium, for the right to exercise that option before it expires.

If you sell an option, you receive a premium from the buyer. In fact, collecting the premium is often one motive for selling options, including those you anticipate will expire without being exercised.

An option premium is not a fixed amount, and typically increases as the option moves in-the-money and decreases if it doesn't move in-the-money.

However, factors such as the price and volatility of the underlying instrument, current interest rates, and the amount of time left before the option expires also affect the premium price.

You can look at the current range of premium prices in the Options Quotations tables in newspapers or on options websites, such as the Options Clearing Corporation (OCC) website.

Options chains are charts showing all the options currently available on a particular underlying instrument.

A chain, also called an options string, provides the latest price quotes for all those contracts as well as the most recent price for the underlying instrument and whether that price is up or down.

Because all this information is available in one place, options chains allow you to assess the market for a particular option quickly and easily. They're a popular feature of online trading and financial information sites.

An options class includes all the calls or all the puts on a single underlying instrument that share some of the same terms, such as contract size and exercise style.

For example, in the case of listed equity options, where all contracts are American-style and cover 100 shares, all the puts on Stock A are members of the same class.

The Options Clearing Corporation issues all exchange-listed securities options in the United States and guarantees all transactions in those options.

The OCC also assigns exercised options for fulfillment, and handles the processing, delivery, and settlement of all options transactions.

The OCC is responsible for maintaining a fair and orderly market in options and is overseen by the Securities and Exchange Commission (SEC). It's jointly owned by the exchanges that trade options.

For an overview of what you should know about options trading, you can check the OCC publication, "Characteristics and Risks of Standardized Options."

An options series includes all the contracts within an options class that have identical terms, including expiration date and strike price. For example, all the calls on Stock A that expire in March and have a strike price of 45 are members of the same options series.

Buying a put option gives you the right to sell the specific financial instrument underlying the option at a specific price, called the exercise or strike price, to the writer, or seller, of the option before the option expires.

You pay the seller a premium for the option, and if you exercise your right to sell, the seller must buy.

Selling a put option means you collect a premium at the time of sale. But you must buy the option's underlying instrument if the option buyer exercises the option and you are assigned to meet the contract's terms.

Not surprisingly, buyers and sellers have different goals. Buyers hope that the price of the underlying instrument drops so they can sell at the exercise price, which is higher than the market price. This way, they could offset the price of the premium, and hopefully make a profit as well.

Sellers, on the other hand, hope that the price stays the same or increases, so they can keep the premium they've collected and not have to lay out money to buy.

A stock option, or equity option, is a contract that gives its buyer the right to buy or sell a specific stock at a preset price during a certain time period.

The exact terms are spelled out in the contract. The same contract obligates the seller, also known as the writer, to meet its terms to buy or sell the stock if the option is exercised. If an option isn't exercised within the set period, it expires.

The buyer pays the seller a premium for the privilege of having the right to exercise, and the seller keeps that premium whether or not the option is exercised. The buyer has the right to sell the contract at any point before expiration, and might choose to sell if the sale provides a profit. The seller has the right to buy an offsetting contract at any time before expiration, ending the obligation to meet the contract's terms.

Stock options are also a form of employee compensation that gives employees -- often corporate executives -- the right to buy shares in the company at a specific price known as the strike price. If the stock price rises, and an employee has a substantial number of options, the rewards can be extremely handsome.

However, if the stock price falls, the options can be worthless. Often, there are time limits governing when employees can exercise their options and when they can sell the stock. These options, unlike equity options, can't be traded among investors.

An uncovered option, also known as a naked option, is an option that is not backed by another position.

For example, if you sell a call option without owning the stock that you would have to deliver if the option holder exercised, the call is uncovered.

Similarly, if you sell an uncovered put, you don't have adequate cash in reserve to fulfill your obligation to purchase the underlying instrument at exercise.

Writing uncovered contracts can put you at significant risk despite the premium you collect when you open the position.

For example, if a naked call option were exercised and assigned to you, you would have to buy the underlying instrument at its market price to be able to meet the terms of the contract. Because of the potential risk, your brokerage firm may restrict your right to write uncovered positions or may require you to trade these options in a margin account.