Call Option
A contract giving the right, but not the obligation, to buy an asset at a set price before expiration.
Also called: call · calls · long call
Written by Javier Sánchez Ros
In plain language
A call buyer pays a premium for the right to buy at the strike price. If the asset finishes above the strike by more than the premium paid, the trade is profitable.
The maximum loss for a call buyer is the premium. That cap is genuine, which makes calls a defined-risk way to express an upside view.
The seller of the call takes the other side: they collect the premium and accept the obligation to deliver at the strike, with losses that grow as price rises.
Worked through
Four calls at $2.35 on a $60,000 account risking 1%
- Premium per contract
- $235
- Risk budget at 1%
- $600
- Contracts affordable
- 2
- Maximum loss
- $470, fully known
Sizing a long call is the cleanest calculation in trading, because the maximum loss is the premium and nothing else. Two contracts at $235 puts $470 at risk, full stop — no stop order required, no gap risk, no slippage on the exit that matters.
The trap is that the number sounds small and the leverage is enormous. Two contracts control 200 shares, which at $58 is $11,600 of exposure for $470. That ratio is why traders buy eight contracts instead of two: the premium still looks modest and the risk is now $1,880, or 3.1% of the account.
The other half of the arithmetic is how often the full loss happens. Unlike a stock position, where a total loss is remote, an option expiring out of the money is worth exactly zero and that is an ordinary outcome rather than a disaster scenario.
So the honest framing is that the risk per contract is certain and the frequency of realising it is high. Size as though the premium will be lost, because a meaningful share of the time it will be.
Seen on a chart
Why it matters
Because the maximum loss is known upfront, the premium paid is your risk per contract — which makes position sizing on long options unusually clean.
Common mistakes
- Treating the capped loss as low risk. Options routinely expire worthless, and 100% losses are common.
- Buying short-dated out-of-the-money calls where time decay dominates the outcome.
- Being right on direction but losing because the move arrived too slowly.
Keep exploring
These concepts are connected. Understanding one usually makes the next one easier.
A contract giving the right, but not the obligation, to sell an asset at a set price before expiration.
The price at which an option contract can be exercised.
The price paid for an options contract.
The date an options contract ceases to exist.
How much an option’s price moves for a $1 move in the underlying.