Call Option

A call option is an options contract that gives its buyer the right, but not the obligation, to buy a specified quantity of an underlying security at a fixed strike price, on or before the contract's expiration date. The Securities and Exchange Commission's investor education states the buyer's side of it in one sentence: a call option "is a contract that gives the buyer the right to buy shares of an underlying stock at the strike price for a specified period of time." The seller of that same contract, in exchange for the premium received, is obligated to sell the underlying at the strike if the buyer exercises.

This page covers the right to buy specifically. The mechanics shared with every options contract, contract size, expiration, premium, and how the price of time and volatility is built into that premium, are covered on our page for options contracts and are not repeated here. The mirror position, the right to sell, is covered on our page for the put option.

Where the underlying price sits relative to the strike has a name, and the name decides whether exercising today would be worth anything. The SEC states the rule for calls directly: a call option is in-the-money "if the strike price is below the actual stock price," and out-of-the-money "if the strike price is above the actual stock price." At-the-money describes the strike and the current price sitting at the same level. Only an in-the-money call has intrinsic value, the amount it would be worth if exercised right now; an out-of-the-money call's entire premium is time value, a bet that it moves into the money before expiration.

The buyer's risk is capped and the writer's is not, and the asymmetry is the single most important fact about which side of a call you are on. A buyer pays the premium once and can lose no more than that, because the worst case is that the right simply expires unused. A writer who does not already own the underlying (an uncovered or "naked" call) receives the premium as the most they will ever make, and if the stock rises well above the strike, they are obligated to deliver shares they must first buy at whatever the market is charging, an exposure with no arithmetic ceiling because a stock's price has no upper bound. Writing a call against shares you already own removes that specific exposure, and that combination has its own page, the covered call.

Breakeven is a number, not a formula, and stating it as a formula is where confusion creeps in. For a call buyer, breakeven is the strike price plus the per-share premium paid. That sounds simple until the contract's size is forgotten: the premium quoted on an options screen is a per-share figure, while the amount actually paid for one contract is that premium multiplied by the contract's size, ordinarily 100 shares for a listed equity option. Confusing the two produces a breakeven that looks right and is off by two orders of magnitude, which is why the worked example below prints every figure rather than describing the formula alone.

A rising underlying does not make a call buyer's paper gain simple to read either, because the premium already paid is sunk. Once the strike is crossed, further gains accrue dollar for dollar with the underlying, but the position only becomes profitable once the underlying clears breakeven, not merely the strike. A buyer who sees the stock cross the strike price and assumes they are now "in profit" is ignoring the premium they already spent to get there.

A buyer pays a premium to a seller for the right to buy a set quantity of the underlying at the strike price on or before expiration. If the right is worth using, the buyer exercises it and the seller must deliver the shares at the strike; if not, the contract expires and the seller keeps the premium.

A hypothetical illustration of breakeven, printed as numbers throughout so the per-share and per-contract figures cannot be confused. Suppose a call option on a stock has a strike price of $60.00 and is quoted at a premium of $3.00 per share. One contract, covering 100 shares, costs $300.00 before fees ($3.00 × 100). The buyer's breakeven is the strike plus the per-share premium: $60.00 + $3.00 = $63.00. Below $63.00 at expiration the position loses money; above it, the buyer is ahead, dollar for dollar with the stock above that level; and the buyer's total loss is capped at the $300.00 paid, no matter how far the stock falls.

A hypothetical illustration of the writer's uncapped exposure on the same contract. Suppose the writer does not own the underlying and the stock instead rallies to $90.00 by expiration. The writer is obligated to deliver 100 shares at the $60.00 strike, receiving $6,000.00, but must first acquire those shares at the market price of $90.00, paying $9,000.00. The loss on the transaction is $3,000.00, against the $300.00 premium received, and nothing in that arithmetic changes if the stock instead rallies to $150.00, where the loss would be $9,000.00. All figures are illustrative and ignore fees.

Pros

• A buyer's maximum loss is known in advance and limited to the premium paid, regardless of how far the underlying falls.
• A relatively small premium controls a much larger quantity of the underlying, which is leverage in economic substance even though nothing is borrowed.
• The buyer's potential gain grows with the underlying's price, with no fixed ceiling on how far it can rise.
• The right, the strike, and the expiration are standardized and published, so the terms can be read rather than negotiated.

Cons

• An uncovered writer's potential loss has no arithmetic ceiling, because a stock's price can rise indefinitely.
• Time works against a buyer even if their view of the stock turns out to be right, because the contract expires and the time-value portion of the premium erodes as expiration approaches.
• The strike price crossing does not mean the position is profitable; that requires clearing the strike plus the premium already paid.
• The per-share premium quoted is not the amount paid for the contract, and treating them as the same number produces the wrong breakeven and the wrong cost.