Call Option
A contract giving the right to buy shares at a set price.
A call option is a contract that gives the buyer the right, but not the obligation, to purchase 100 shares of an underlying stock at a specified strike price on or before a set expiration date. The buyer pays a premium for this right, while the seller (writer) of the call takes on the obligation to sell shares if assigned.
Why It Matters
Call options are the most fundamental bullish instrument in options trading. They let you control 100 shares of stock for a fraction of the cost of buying those shares outright. This leverage means you can participate in upside moves with defined risk — the most you can lose is the premium you paid. For sellers, writing calls generates income but carries the obligation to deliver shares at the strike price if the stock rises above it.
Understanding calls is essential because they are a building block of nearly every options strategy. Covered calls, bull call spreads, iron condors, straddles — they all include call options as a component.
How It Works
When you buy a call, you are paying for the right to purchase shares at the strike price. If the stock rises above the strike, the call gains intrinsic value dollar-for-dollar with the stock. If the stock stays below the strike through expiration, the call expires worthless and you lose the premium paid.
Key mechanics:
- Buyer (long call): Pays premium, has the right to buy shares. Maximum loss is the premium. Maximum gain is theoretically unlimited.
- Seller (short call): Collects premium, has the obligation to sell shares. Maximum gain is the premium collected. Maximum loss is theoretically unlimited (if naked) or capped (if covered or part of a spread).
Factors that increase a call's value:
- Stock price rising (higher delta exposure)
- More time to expiration (more time value)
- Rising implied volatility (higher vega exposure)
Factors that decrease a call's value:
- Stock price falling
- Time passing (theta decay)
- Falling implied volatility
Calls can be exercised early if they are American-style options, which most equity options are. However, early exercise is usually suboptimal because it forfeits remaining time value. The main exception is deep ITM calls just before an ex-dividend date, where capturing the dividend may justify early exercise.
Quick Example
Stock ABC trades at $50. You buy the $52 call expiring in 30 days for $1.50. Your total cost is $150 (one contract controls 100 shares). Your breakeven at expiration is $53.50 ($52 strike + $1.50 premium).
If ABC rises to $58 at expiration, your call is worth $6.00 in intrinsic value. Your profit is $6.00 - $1.50 = $4.50 per share, or $450 per contract — a 300% return on your $150 investment. If ABC finishes at $50, the call expires worthless and you lose $150.