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What Is an Option? Options Trading Explained

By Dennis Bosmans · Updated June 2026 · 2 min read · Risk disclaimer

An option is a contract that gives you the right — but not the obligation — to buy or sell 100 shares of a stock at a fixed price before a set date. That single idea, the right without the obligation, is what makes options so flexible: you can bet on direction, generate income, or protect a portfolio, all with risk you define up front.

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Calls and puts: the two building blocks

There are only two kinds of option. A call gives you the right to buy the stock at the strike price; you buy calls when you expect the price to rise. A put gives you the right to sell at the strike; you buy puts when you expect a fall or want to protect shares you own.

Each contract represents 100 shares. You can be the buyer (paying a premium for the right) or the seller/writer (collecting the premium and taking on the obligation). Combining long and short calls and puts builds every strategy that exists.

The four terms you must know

Strike price: the fixed price at which the option can be exercised. Premium: the price you pay or receive for the contract. Expiration: the date the option ends. Underlying: the stock or index the option is based on.

Two more shape an option’s price: intrinsic value (how far in-the-money it already is) and extrinsic value (the time-and-volatility premium on top), which decays to zero by expiration.

Why people trade options

Leverage: one contract controls 100 shares for a fraction of the cost. Income: selling options (covered calls, cash-secured puts) collects premium. Hedging: a put acts like insurance on a stock position.

The key advantage over buying stock is defined risk — when you buy an option, the most you can lose is the premium, no matter how far the stock moves against you.

Worked example. A stock trades at $100. You buy one 30-day $105 call for $2.00, paying $200 for the right to buy 100 shares at $105. If the stock rises to $112, the call is worth at least $7.00 — a $500 gain. If it never reaches $105, the most you lose is the $200 premium.
Key takeaways

Frequently asked questions

What is the difference between a call and a put?

A call is the right to buy at the strike (bullish); a put is the right to sell at the strike (bearish or for protection).

Can I lose more than I invest in an option?

Not if you buy options — your maximum loss is the premium paid. Selling uncovered (naked) options is where larger losses can occur.

Do I have to exercise an option?

No. Most traders simply buy and sell the contract itself for its market value before expiration rather than exercising it.

Related strategies:
Long CallLong PutCovered Call
Related guides: (all guides):
Call vs Put OptionsHow to Trade Options: A Beginner’s GuideBest Options Strategy for Beginners

Educational use only. Quotes are delayed ~15 minutes and nothing here is financial advice. Options trading involves substantial risk of loss. Privacy Policy · Terms & Conditions.