If you already trade stocks, you know the deal: you buy shares, you own part of a company, and you can hold them for as long as you like. Options work differently. You are not buying the company — you are buying or selling a contract about the company's stock, and that contract stops existing on a specific date.
That single difference explains most of what beginners find strange about options: why the price can fall while the stock rises, why "cheap" contracts are not automatically low risk, and why the same contract can mean capped risk for one trader and an open-ended obligation for another.
One sentence to rememberThe buyer of an option holds a right. The seller of that same option carries an obligation. Everything else — strike, premium, expiration — is just the wording of the deal.
What a call and a put actually are
A standard-size US equity options contract covers 100 shares of the underlying stock. Two contract types exist, and every position you can take is one of them, bought or sold.
- A call gives its holder the right, but not the obligation, to buy 100 shares at a fixed price. The seller of that call takes on the obligation to deliver those shares if the contract is assigned.
- A put gives its holder the right, but not the obligation, to sell 100 shares at a fixed price. The seller of that put takes on the obligation to buy those shares if the contract is assigned.
The fixed price is the strike. The date the right ends is expiration. The money that changes hands when the contract is opened is the premium, and it belongs to the seller regardless of what happens next.
Reading a contract
An options quote is really five pieces of information stacked together:
| Element | Example | What it decides |
|---|---|---|
| Underlying | XYZ | Which stock the contract refers to |
| Expiration | Oct 16 | The last day the right exists |
| Strike | $55 | The price at which shares change hands |
| Type | Call / Put | Right to buy, or right to sell |
| Premium | $1.20 | Price per share — multiply by 100 for the contract |
The last row is where beginners most often lose money by accident. A premium of $1.20 is quoted per share. One contract therefore costs $120 plus fees, not $1.20. Ten contracts cost $1,200 and control 1,000 shares.
Traditional monthly options expire on the third Friday of the month, though weekly and even daily expirations exist on many underlyings, and LEAPS run out as far as roughly two years and eight months.
The four basic positions
Every options strategy, however complicated it looks, is built from these four. The examples assume XYZ trading at $50, a 55-strike call priced at $1.20 and a 45-strike put priced at $0.90.
| Position | You want | Maximum loss | Maximum gain |
|---|---|---|---|
| Long call (buy the right to buy) | Stock up, before expiry | $120 — the premium paid | Theoretically unlimited |
| Long put (buy the right to sell) | Stock down, before expiry | $90 — the premium paid | $4,410 (strike less premium, ×100) |
| Short call (sell the obligation to deliver) | Stock flat or down | Theoretically unlimited if uncovered | $120 — the premium received |
| Short put (sell the obligation to buy) | Stock flat or up | $4,410 if the stock goes to zero | $90 — the premium received |
Notice the asymmetry. For a buyer, the premium paid is the maximum loss — that is the defining feature of long options. For a seller, the premium received is the maximum gain, while the loss side stays open: an uncovered, or naked, call has a maximum loss that is theoretically unlimited, because there is no ceiling on where a stock can trade.
How a call plays out
You buy one XYZ 55-strike call for $1.20 — a cost of $120. Break-even at expiration is the strike plus the premium:
Long call break-even = strike + premium paid = $55 + $1.20 = $56.20
At expiration, three things can happen:
- XYZ at $60. The right to buy at $55 is worth $5.00 per share, so the contract is worth $500. Subtract the $120 paid and you are up roughly $380 before fees.
- XYZ at $56. The contract is worth $100 — real value, but less than you paid. You lose about $20.
- XYZ at $54. Nobody exercises the right to buy at $55 when shares trade at $54. The contract expires worthless and the $120 is gone.
Read that last case again. The stock went up, from $50 to $54, and the call buyer still lost everything. Direction alone was not enough: the move had to clear the strike, cover the premium, and do it before the deadline.
How a put plays out
You buy one XYZ 45-strike put for $0.90 — a cost of $90. Break-even runs the other way:
Long put break-even = strike − premium paid = $45 − $0.90 = $44.10
If XYZ falls to $40 by expiration, the right to sell at $45 is worth $5.00 per share, or $500; after the $90 paid, that is roughly $410. If XYZ sits anywhere at or above $45, the put expires worthless and the loss is the $90 premium.
A put's gain is large but not unlimited, because a stock cannot fall below zero. That bound is what makes the short-put side calculable: sell that put, and you have accepted a potential obligation to buy 100 shares at $45 — $4,500 of stock — in exchange for $90.
Two numbers, not oneBefore any options trade, write down the premium at risk and the notional exposure (100 × strike, per contract). They answer different questions: what you can lose on the ticket, and what you would actually be committing to if the contract is exercised or assigned.
Why the option moves when the stock doesn't
An option's premium has two parts.
- Intrinsic value — what the contract would be worth if it expired right now. A 45-strike call with the stock at $50 has $5.00 of intrinsic value. An out-of-the-money option has none.
- Extrinsic value — everything else you are paying for: the time remaining, and how much movement the market currently expects.
Extrinsic value is worth exactly zero at expiration. Between now and then it drains away, and it also swells or collapses as expectations about volatility change. This is why a contract bought before an earnings announcement can lose value the morning after the stock moves in your favour: the uncertainty you paid for has been resolved, and the market is no longer pricing it in.
Moneyness is the shorthand for where a strike sits relative to the stock. With XYZ at $50:
| Strike | Call is… | Put is… |
|---|---|---|
| $45 | In the money | Out of the money |
| $50 | At the money | At the money |
| $55 | Out of the money | In the money |
Far out-of-the-money contracts are cheap for a reason: they need a large move in a short window to be worth anything. A low ticket price is not the same as a low probability of losing all of it.
Expiration, exercise and assignment
US equity options are generally American-style, meaning the holder can exercise at any time up to expiration; European-style contracts, common for index products, can only be exercised during a period on the expiration date itself. If you are short an American-style option, early assignment is always possible — and it becomes more likely on a short call when a dividend is approaching and little extrinsic value remains.
At expiration, contracts do not simply vanish. The OCC applies an administrative procedure known as exercise by exception: options in the money by $0.01 or more are exercised unless the clearing member instructs otherwise, and individual brokerages may apply different thresholds for their customers. Assignment is then allocated randomly by the OCC to clearing members, who assign their own customers according to their own method.
In practice, that means two things:
- An in-the-money long option you forgot about can turn into 100 shares per contract — and a cash requirement you did not plan for. If you do not want the stock, close the position before expiration.
- Assignment on a short option is not something you choose or can predict. It arrives, and you find out afterwards.
Selling options is a different activityBuying a call or a put risks a known amount. Writing one accepts an obligation whose cost is decided later by the market. Brokers gate these strategies behind approval levels for that reason, and require you to read the "Characteristics and Risks of Standardized Options" disclosure first. Read it — it is the actual rulebook for the contracts you are trading.
Sizing an options position
The arithmetic from risk management 101 still applies, with one adjustment: your unit is a contract covering 100 shares, not a single share. Risking 1% of a $10,000 account means $100 at risk — which is less than one contract of many liquid options.
Two traps follow from that:
- Rounding up. When your calculated size is 0.8 contracts, one contract is a 25% overshoot of your intended risk. There is no fractional contract to fall back on, so the honest answer is often "this trade is too large for this account".
- Treating maximum loss as unlikely loss. The premium is genuinely the worst case for a buyer — but unlike a stop-loss on shares, a total loss on a long option is an ordinary outcome, not a tail event. A contract that expires out of the money is worth nothing at all.
What to log when you journal options
The fields that make a stock journal useful are not quite enough here, because two options trades on the same stock in the same direction can be completely different trades. Add:
- contract type, strike and expiration date — plus days to expiration at entry;
- premium per share and per contract, with the number of contracts;
- the underlying's price when you opened and closed, not only the option's;
- implied volatility at entry, if your broker shows it, and whether an earnings date fell inside the contract's life;
- how the position ended: closed, expired worthless, exercised or assigned;
- for multi-leg positions, a shared tag so the legs are reviewed as one trade.
Without days-to-expiration and the underlying's move, your history cannot tell you the most useful thing it knows: whether your losing options trades were wrong about direction, or right about direction and wrong about time.
Five mistakes that cost beginners money
- Multiplying wrong. Reading $2.50 as the cost of a contract rather than $250.
- Buying far out-of-the-money contracts because they are cheap. Low price reflects low odds, not a bargain.
- Being right too slowly. The thesis plays out three weeks after the contract expired.
- Ignoring the spread. On illiquid options the gap between bid and ask can be a meaningful share of the premium, paid twice — in and out.
- Letting expiration arrive unattended. An in-the-money contract left open becomes shares, whether or not you were watching.
Key takeaways
- A call is the right to buy 100 shares at the strike; a put is the right to sell them. The seller of each holds the matching obligation.
- Premium is quoted per share — one standard contract is 100 shares, so multiply before you decide anything.
- Break-even is strike plus premium for a long call, strike minus premium for a long put — being right on direction is not enough.
- Buyers risk the premium; uncovered sellers face open-ended risk and assignment they cannot control.
- Log strike, expiration, days to expiration and how the position ended, or your options history will not explain itself later.
Sources and further reading
- FINRA: Options
- Options Industry Council: Options exercise FAQ
- Options Industry Council: Options assignment FAQ
- U.S. SEC Investor.gov: Call option
- U.S. SEC Investor.gov: Put option
See the payoff before you place the trade
Sereo's options payoff calculator draws the profit and loss curve, break-even, maximum profit and maximum loss for a contract — so the shape of the risk is on screen before the order is.
This article is educational and does not constitute investment advice. Options involve risk and are not suitable for every investor; you can lose your entire investment, and uncovered positions can lose more. Examples are illustrative and exclude fees and taxes. Read the "Characteristics and Risks of Standardized Options" before trading, do your own research and manage your own risk.
