Options Basics: Calls, Puts and Premiums in Plain English

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A colleague mentions over lunch that he sold a put on a stock he likes, and you nod along while quietly running through the vocabulary in your head. Calls, puts, strikes, premiums. The terms sound complicated, but the structure is a short list of ideas: an option is a contract with a price, a deadline and a right attached to it. This guide walks through those ideas in order, so the next time the conversation turns to options you can follow each piece and see where the risk sits.

Key Takeaways

• An option is a contract that gives its buyer the right, but not the obligation, to buy or sell an underlying asset at a set price before a set date.
• A call is the right to buy and a put is the right to sell; the price paid for either is the premium.
• One standard equity option contract usually covers 100 shares, so premiums quoted per share are multiplied by 100.
• Buyers can lose the entire premium, while sellers can take on obligations that are larger than the premium received.
• Options expire, so time works against the holder in a way it does not for shares.

Step 1: Start with the contract itself

An option is a standardized contract between a buyer and a seller. It names an underlying asset, most often a stock or an exchange-traded fund, a strike price at which the transaction would occur, and an expiration date after which the contract ends. The buyer pays the seller a price for the right the contract grants. That price is the premium.

The buyer's right is optional, which is where the name comes from. The seller's side is the opposite: if the buyer chooses to use the right, the seller must follow through. That asymmetry, a right on one side and an obligation on the other, is the key to everything else, including why risks differ so much between buying and selling.

Step 2: Calls and puts

A call option gives the buyer the right to buy the underlying at the strike price. A put option gives the buyer the right to sell the underlying at the strike price. People often explain a call as a bet that a price rises and a put as a bet that it falls, which is a useful shorthand, although options are also used for other purposes, such as limiting the downside on shares someone already owns.

It helps to think in terms of the strike relative to the current price. A call is in the money when the market price is above the strike, because the right to buy lower is worth something. A put is in the money when the market price is below the strike. Options out of the money have no immediate exercise value and carry only the chance of getting there before expiration.

Step 3: Premiums and what they are made of

The premium is quoted per share, and a standard U.S. equity contract covers 100 shares. A quoted premium of one dollar therefore means a hundred dollars for the contract. The numbers here are purely for arithmetic and are not examples of real prices.

Premium has two parts. Intrinsic value is the amount by which the option is in the money. Time value is whatever remains, which reflects the chance that the option gains value before expiration. Time value is influenced by how long remains until expiration, how far the strike is from the current price, and how volatile the underlying is expected to be. Higher expected volatility generally raises premiums on both calls and puts, because larger price swings make a payoff more likely. Because time value shrinks as expiration nears, an option can lose value even if the stock price does not move.

Step 4: Exercise, assignment and expiration

There are three ways an option position can end.

• The holder sells the contract before expiration, taking whatever the market price is then.
• The holder exercises the option, and the seller on the other side is assigned, which means the seller must deliver or buy the shares at the strike.
• The option expires; if it is out of the money, it expires worthless and the premium is the buyer's loss.

Most listed options are closed out in the market rather than exercised, but assignment is a real possibility for sellers, sometimes before expiration. Contract specifications, settlement rules and early-exercise features are published by the options clearing organization and your broker; read them before trading anything.

Step 5: Where the risk sits

The risk profile differs sharply by role. A buyer of a call or put can lose no more than the premium paid, but that loss can be total and can happen quickly as expiration approaches. A seller receives the premium up front but takes on an obligation. Selling a call without owning the shares, called a naked call, carries theoretically unlimited risk because a stock price has no ceiling. Selling a put carries the risk of having to buy shares at the strike even if the market price has fallen far below it.

Brokers therefore require approval levels for options trading, and you should read the options disclosure document, formally called the Characteristics and Risks of Standardized Options, that brokers provide. FINRA and the SEC's Investor.gov also publish plain-language guidance. Options are not suited to everyone, and for many self-directed investors the most useful first step is simply knowing the vocabulary well enough to judge whether they want to go further. Working with a qualified advisor and self-directing are both legitimate approaches.

An illustrative walk-through (not a forecast)

This hypothetical is a teaching example, not a suggestion to do anything. Imagine a surgeon who owns shares of a company and, over a weekend, reads about what a protective put would involve. She writes down three facts: the strike she would choose, the expiration date, and the premium per share.

She then multiplies the premium by 100 to see the cost for one contract, and compares that figure with the number of shares she owns, which tells her how many contracts it would take to cover her position. She notes that the put's cost is paid up front and is lost if the share price stays above the strike through expiration. She also notes that time value will fade as the date approaches.

She stops there. The reading produced a list of questions for her broker about approval levels and contract specifications, and a clearer sense of what she does not yet know. Whether options belong in her portfolio at all remains a separate decision.

Frequently Asked Questions

What is the difference between a call and a put?

A call gives its holder the right to buy the underlying at the strike price, and a put gives the holder the right to sell at the strike price. Both rights expire on a set date.

What is an option premium?

The premium is the price the buyer pays the seller for the contract, quoted per share. A standard equity option covers 100 shares, so the total cost is the quoted premium times 100.

Can you lose more than you pay for an option?

Buyers cannot lose more than the premium they paid. Sellers can lose more than the premium they received, and the exposure can be very large for uncovered positions.

What happens when an option expires?

An in-the-money option may be exercised automatically at expiration depending on brokerage and clearing rules, while an out-of-the-money option expires worthless. Check your broker's expiration procedures, because they vary in the details.

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