What you are actually buying and selling when you trade options
An option is a contract that gives you the right—but not the obligation—to buy or sell a stock at a set price by a certain date. You do not own the stock itself. Instead, you own a contract that lets you decide later whether to make that trade. The person on the other side of the contract is betting you will not exercise that right, or will exercise it in a way that loses them money.
There are two types of options. A call option gives you the right to buy a stock at a fixed price. A put option gives you the right to sell a stock at a fixed price. Each contract covers 100 shares, though you pay a much smaller amount upfront called the premium. The premium is what you pay to own the contract; it is not the price of the stock itself.
Options have an expiration date. After that date, the contract is worthless and disappears. This is different from owning stock, which you can hold forever. The fixed price in the contract is called the strike price. If the stock price moves in your favor before expiration, the contract becomes more valuable and you can sell it for a profit. If it moves against you, the contract loses value.
Key Takeaways
- An option contract gives you the right to buy (call) or sell (put) 100 shares at a set price by a set date, but you do not have to exercise that right.
- You pay a premium upfront to own the contract, which is a small fraction of what 100 shares would cost.
- Options expire on a specific date and become worthless after that date if you have not used them.
- The value of an option changes based on the stock price, time remaining, and how volatile the stock is.
- You can close out an option contract by selling it back before expiration instead of exercising it.
How the price of an option changes
The premium you pay for an option is not fixed. It moves constantly during the trading day, just like a stock price does. Several things push that price up or down. The most obvious is the stock price itself. If you own a call option and the stock price rises, your contract becomes more valuable because you have the right to buy at the lower strike price. If the stock price falls, your call option loses value.
Time also matters. As the expiration date gets closer, the option loses value. This happens even if the stock price does not move. On the last day before expiration, an option that is out of the money (meaning it would lose money if you exercised it) is worth almost nothing. Traders call this time decay. The less time left, the faster the decay accelerates.
How much the stock price swings around—called volatility—also changes what an option costs. If a stock bounces up and down wildly, options on that stock are more expensive because there is a bigger chance the contract will end up profitable. If a stock barely moves, options are cheaper. This is true even if the stock price itself has not changed.
The difference between buying and selling options
When you buy an option, you pay the premium and own the contract. Your maximum loss is the premium you paid. Your profit comes from selling the contract later for more than you paid, or from exercising it if it is profitable. Most options traders never exercise; they buy and sell the contracts themselves.
When you sell an option, you collect the premium upfront. You are betting the contract will expire worthless or lose value. If you sell a call, you are betting the stock will not rise above the strike price. If you sell a put, you are betting the stock will not fall below the strike price. Your profit is the premium you collected. Your loss can be much larger than the premium if the stock moves sharply against you.
Selling options is riskier than buying them because your potential loss is not capped. Many brokers require you to have a certain amount of money in your account before they let you sell options, and some require special permission or training. Buying options is simpler: you pay the premium, and that is your maximum loss.
What happens when an option expires
On the expiration date, the option contract stops existing. If you own a call option and the stock price is above the strike price, the contract is "in the money." Most brokers will automatically exercise it for you, meaning they buy 100 shares at the strike price and sell them at the current market price, depositing the profit in your account. If the stock price is below the strike price, the call is worthless and expires for nothing.
The same logic applies to puts, but in reverse. If you own a put and the stock price is below the strike price, the put is in the money and your broker will usually exercise it automatically. If the stock price is above the strike price, the put expires worthless.
You do not have to wait for expiration. You can sell your option contract back to the market at any time during the trading day before expiration. This is how most traders close out their positions. Selling early lets you lock in a profit or cut a loss without waiting for expiration or dealing with automatic exercise.
How options are priced in real time
Option prices are quoted as a per-share amount, but remember that one contract covers 100 shares. If an option is quoted at $2.50, you pay $250 to buy one contract ($2.50 × 100). The price you see on your broker's screen changes throughout the trading day as buyers and sellers place orders.
The bid price is what buyers are willing to pay right now. The ask price is what sellers are asking. The difference between them is called the spread. When you buy, you pay the ask price. When you sell, you receive the bid price. A wide spread means it costs more to enter and exit the trade. Options on popular stocks have tight spreads; options on obscure stocks have wide spreads.
The bid-ask spread can be a real cost. If you buy an option at the ask price and immediately sell it at the bid price, you lose money even if nothing else changed. This is why traders often place limit orders instead of market orders—they specify the price they are willing to pay or accept, and wait for a match rather than taking whatever price is available right now.
Why people trade options instead of stocks
Options let you control 100 shares for a fraction of the cost of buying the stock outright. If a stock costs $50 per share, buying 100 shares costs $5,000. A call option on that stock might cost $200 to $300. This leverage means your percentage gain or loss is much larger. If the stock rises 10 percent, your option might rise 50 percent or more. If it falls 10 percent, your option might lose 50 percent or more.
Options also let you profit if a stock falls. With a put option, you make money when the stock price goes down. With a regular stock, you only make money when the price goes up. This flexibility attracts traders who want to bet on different market directions.
Options also have a defined time frame. Some traders like this because it forces a decision: you have until expiration to be right, and then the contract is gone. Other traders use options to hedge their stock holdings—they buy a put option as insurance in case the stock price drops.
Common mistakes when starting out with options
New traders often underestimate how fast options lose value as expiration approaches. Buying an option far out of the money and hoping it will eventually move into the money is a common losing trade. Time decay works against you every single day, and if the stock does not move, you lose money even if you were right about the direction.
Another mistake is not understanding the bid-ask spread. Buying an illiquid option—one that does not trade often—can mean a very wide spread. You might buy at $2.50 and immediately see it quoted at $1.80 because the spread is so wide. You have lost money before the stock even moved.
Many new traders also forget that options are leveraged. A small move against you can wipe out your entire premium. Options are not a way to trade with less risk; they are a way to trade with more risk per dollar invested. You can lose 100 percent of what you paid for an option, whereas a stock can only fall to zero and you would lose 100 percent of what you paid for that too—but options get there much faster.
Frequently Asked Questions
Do I have to exercise an option or can I just sell the contract?
You can sell the contract back to the market at any time before expiration. Most traders do this instead of exercising. You do not have to own the stock or have the cash to buy it. You simply sell the contract for whatever it is worth at that moment.
What happens if I own a call option and the stock gets delisted or goes bankrupt?
The option becomes worthless and expires for nothing. You lose the premium you paid. The strike price and expiration date no longer matter because there is no stock to buy or sell. Your broker will not exercise the contract.
Can I sell an option I do not own?
Yes, this is called selling to open. You collect the premium upfront and are obligated to buy or sell 100 shares at the strike price if the buyer exercises. You must have enough cash or buying power in your account, and your broker must allow it. This is riskier than buying options because your loss is not capped.
How do I know if an option is a good price?
There is no single "good price"—it depends on your outlook for the stock, how much time is left, and how volatile the stock is. Comparing the option price to historical prices for that same strike and expiration can help. Many traders use tools like implied volatility to decide whether an option is cheap or expensive relative to its history.
What is the difference between American and European options?
American options can be exercised any time up to and including the expiration date. European options can only be exercised on the expiration date itself. Most options traded in the U.S. are American. The difference matters most for put options, where early exercise can sometimes be profitable.