TL;DR: Options in Three Sentences
An options contract gives the buyer the right—but not the obligation—to buy or sell a stock at a fixed price before a set date. The buyer pays a premium for that right; the seller collects the premium and accepts the obligation if the buyer exercises. Understanding this exchange—right vs. obligation, premium vs. exposure—is the foundation of every options strategy.
What Is an Options Contract?
Two parties enter every options trade. The buyer (holder) pays an upfront premium and acquires a right. The seller (writer) receives that premium and assumes an obligation if the buyer exercises. Unlike a stock trade, where both sides exchange ownership immediately, an options contract separates the right to trade from the obligation to trade—and that asymmetry is what makes options powerful.
In U.S. equity markets, one standard contract covers 100 shares of the underlying stock. So if an option trades at a $2.50 premium, one contract costs $250 (2.50 × 100), not $2.50. This multiplier is one of the most common surprises for first-time options traders.
All U.S. listed equity options are cleared through the Options Clearing Corporation (OCC)—the central counterparty that guarantees every trade and eliminates the risk of counterparty default. Knowing the OCC sits in the middle is why you don’t need to worry about the person on the other side of your trade walking away.
Calls vs. Puts: The Only Two Types
Every option is either a call or a put.
- Call option: The right to buy the underlying stock at the strike price. Calls become more valuable when the stock price rises above the strike.
- Put option: The right to sell the underlying stock at the strike price. Puts become more valuable when the stock price falls below the strike.
Think of a call as locking in a purchase price—like a home buyer securing the right to buy at today’s price even if prices rise. A put is the mirror image: locking in a sale price as insurance against a price drop. Buyers of calls are bullish; buyers of puts are bearish or hedging. Sellers of calls are neutral-to-bearish; sellers of puts are neutral-to-bullish.
The Three Key Terms: Strike, Expiry, Premium
Strike Price
The strike price (also called exercise price) is the fixed price at which the option holder can buy (call) or sell (put) the underlying shares. You choose the strike when you buy the contract; it does not change after purchase. A $210 Apple call gives you the right to buy 100 shares of AAPL at $210 each, regardless of where the market price goes.
Expiration Date
Every option has an expiration date—the last day it can be exercised. An option that is out of the money at expiration expires worthless, and the buyer forfeits 100% of the premium paid. U.S. equity options come in several expiration cycles:
- Standard monthly expirations: Typically the third Friday of each calendar month.
- Weekly expirations (weeklies): Expire every Friday. Introduced by Cboe in 2005, weeklies now account for the majority of U.S. options volume by contract count.
- LEAPS (Long-term Equity AnticiPation Securities): Options with expirations up to three years out—useful for longer-duration directional or hedging strategies.
Premium
The premium is the price paid by the buyer or received by the seller. It is quoted per share, then multiplied by 100 for a standard contract. The premium is the buyer’s total maximum loss and cost of entry. For the seller, it is income collected upfront in exchange for taking on an obligation that can be far larger.
In the Money, At the Money, Out of the Money
These three phrases describe where the current stock price stands relative to the strike. They matter because they tell you how much immediate exercise value an option carries.
| Term | For a Call | For a Put | Intrinsic Value |
|---|---|---|---|
| In the Money (ITM) | Stock price > Strike | Stock price < Strike | Positive—exercise has immediate value |
| At the Money (ATM) | Stock price ≈ Strike | Stock price ≈ Strike | Zero or near zero |
| Out of the Money (OTM) | Stock price < Strike | Stock price > Strike | Zero—no immediate exercise value |
Intrinsic Value vs. Extrinsic Value
Every option premium breaks into two parts:
Premium = Intrinsic Value + Extrinsic (Time) Value
Intrinsic value is the immediate exercise value—what you would gain if you exercised the option right now. The formulas:
- Call intrinsic value = max(0, Stock Price − Strike Price)
- Put intrinsic value = max(0, Strike Price − Stock Price)
An OTM option has zero intrinsic value. An ITM option has positive intrinsic value. ATM options have approximately zero.
Extrinsic value—also called time value—is the portion of the premium above intrinsic value. It reflects two things:
- Time to expiration: More days remaining means more opportunity for the stock to move in your favor. This value erodes continuously as expiration approaches. The rate of that erosion is captured by theta, one of the options Greeks. Theta decay accelerates sharply in the final 30 days before expiration.
- Implied volatility (IV): When the market expects large price swings—say, ahead of an earnings announcement—implied volatility rises and premiums inflate. If you buy a high-IV option and volatility collapses after the event (even if the stock moves in your direction), the option can still lose value. Traders call this an IV crush.
A Worked Example: Apple Call Option
Apple (AAPL) is trading at $200. You believe the stock will rise over the next month and buy one call option:
- Strike: $210 (out of the money at purchase)
- Expiration: 30 days out
- Premium: $3.00 per share → $300 total cost (one contract = 100 shares)
Your breakeven at expiration is $213 (strike $210 + $3.00 premium). The table below shows outcomes at different stock prices:
| AAPL at Expiry | Moneyness | Intrinsic Value / Share | P&L per Contract |
|---|---|---|---|
| $190 | Deep OTM | $0.00 | −$300 |
| $205 | OTM | $0.00 | −$300 |
| $210 | ATM (at strike) | $0.00 | −$300 |
| $213 | Breakeven | $3.00 | $0 |
| $220 | ITM | $10.00 | +$700 |
| $230 | Deep ITM | $20.00 | +$1,700 |
The buyer’s maximum loss is capped at the $300 premium. The potential gain is theoretically uncapped. That asymmetry—defined downside, open upside—is the core appeal of buying calls. For the seller collecting the premium, the asymmetry runs the other way: the $300 collected is the maximum gain, while losses are theoretically unlimited if the stock surges.
Call Option Payoff at Expiration
The chart below shows the profit-and-loss profile of the $210 call from the example above, plotted across a range of stock prices at expiration. Notice the characteristic hockey-stick shape: flat loss region below the strike, then a linear gain above the breakeven.
How Time Decay Accelerates Near Expiration
A $3.00 option on day one is not the same as a $3.00 option five days before expiry. The extrinsic (time) value in the premium decays continuously—but not linearly. Decay follows roughly the square root of time remaining, which means the final 30 days see significantly faster erosion than the first 30 days. This is theta decay in action.
For sellers of options, this acceleration is a friend: collected premium bleeds away faster as expiration nears. For buyers holding through expiration, the clock is an adversary.
American vs. European Style: When Can You Exercise?
U.S. equity options on individual stocks (Apple, Nvidia, Tesla, etc.) are American-style: the holder can exercise at any point between purchase and expiration. In practice, most options are sold in the market rather than exercised, because selling captures any remaining time value—exercising forfeits it.
Some index options—notably the S&P 500 SPX contract at Cboe—are European-style: exercise is only permitted at expiration, and settlement is cash-based (you receive the difference in value, not actual shares). European-style options are somewhat easier to price analytically, which is why SPX underpins most volatility benchmarks including the CBOE Volatility Index (VIX).
The practical implication: if you’re holding an American-style deep ITM option and want to close the position, sell it—don’t exercise, unless capturing a dividend makes early exercise economically rational.
Four Common Mistakes (and Why They Happen)
1. Treating Far-OTM Options as Lottery Tickets
A $0.20 option looks cheap. But it requires the stock to jump 20% in two weeks to pay off meaningfully. The probability of that outcome is reflected in the price: low premium often means low probability. Most OTM options expire worthless—a fact that professional sellers exploit through strategies like covered calls and cash-secured puts.
2. Ignoring Implied Volatility Before Buying
IV is the price of uncertainty baked into the premium. Buying options when IV is elevated—say, the day before earnings—means you’re paying a high price for uncertainty that may evaporate the moment the news lands. Even a 10% stock move in the right direction can leave the option with a lower premium if IV collapses from 80% to 30% overnight. Always check whether you’re buying premium at historically high or low volatility.
3. Not Knowing the 100-Share Multiplier
One contract covers 100 shares. A $5.00 premium per share means $500 per contract, not $5. Many beginners size positions incorrectly because they forget this multiplier, leading to far more (or less) exposure than intended.
4. Exercising When You Should Sell
If you own an ITM option and want to realize the gain, the right move is almost always to sell the option, not exercise it. Selling captures intrinsic value plus any remaining time value. Exercising captures intrinsic value only and abandons the time premium you paid for.
What to Learn Next
Options 101 covers the foundation. The natural progression from here:
- The Greeks: Delta (price sensitivity), gamma (rate of delta change), theta (time decay), and vega (volatility sensitivity). These four measures let you quantify an option’s exposure to each input.
- Basic strategies: Covered calls, protective puts, vertical spreads, straddles. These combine options (or options with stock) to define risk precisely.
- Implied volatility and IV rank: How to read whether options are cheap or expensive relative to history—the single biggest contextual factor in whether to buy or sell premium.
- The Black-Scholes model: The 1973 framework that gave the financial world a way to price options mathematically, revolutionizing derivatives markets and earning its authors the Nobel Prize in Economics.
Sources
- FINRA: Options — Investor Education — authoritative source for contract size (100 shares), call/put definitions, strike, expiry, premium, intrinsic value, American/European style, buyer max loss, and seller risk.
- Options Clearing Corporation (OCC) — central counterparty clearing for all U.S. listed equity and index options.
- Cboe Options Institute — exchange-level education resources on equity and index options, including weekly expirations history.
Disclosure: This article was produced with AI assistance and reviewed before publication. It is for informational purposes only and is not investment advice.