What Is an Option Premium?
An option premium is the price paid by the buyer (and received by the seller) for an options contract. It represents the total cost of acquiring the right to buy (call) or sell (put) the underlying stock at the strike price before expiration. The premium is quoted on a per-share basis, so the total cost of one contract (100 shares) is the premium multiplied by 100. For example, a premium of $3.50 costs $350 per contract.
Understanding what drives option premiums is essential for every options trader. A premium that seems cheap may actually be expensive relative to the stock's expected volatility, while a premium that looks expensive may actually be a fair price given upcoming catalysts. By decomposing premiums into their components and evaluating each, you can make more informed trading decisions.
Components of Option Premium
Premium Calculation Example
- 1Calculate intrinsic value: max(0, $105 - $100) = $5.00
- 2Using Black-Scholes, the total call premium = $7.85
- 3Time value = Total premium - Intrinsic value = $7.85 - $5.00 = $2.85
- 4Cost per contract = $7.85 × 100 = $785
- 5Put premium via put-call parity: approximately $2.31
- 6Put intrinsic value: max(0, $100 - $105) = $0 (out-of-the-money)
- 7Put time value: $2.31 - $0 = $2.31 (all time value)
Factors That Affect Option Premium
| Factor | Effect on Call Premium | Effect on Put Premium | Magnitude |
|---|---|---|---|
| Stock price rises | Increases | Decreases | Major (Delta) |
| Time passes | Decreases | Decreases | Major (Theta) |
| IV increases | Increases | Increases | Major (Vega) |
| Rates increase | Increases slightly | Decreases slightly | Minor (Rho) |
| Dividend increase | Decreases | Increases | Minor to moderate |
| Strike price higher | Decreases | Increases | Structural |
Intrinsic Value vs. Time Value
Intrinsic value is the portion of the premium that reflects the option's immediate exercise value. A call option is in-the-money when the stock price exceeds the strike price; the intrinsic value equals the difference. Out-of-the-money options have zero intrinsic value. Intrinsic value cannot be negative and represents the minimum value of an ITM option.
Time value represents the probability premium: the extra amount traders are willing to pay above intrinsic value for the chance that the option becomes more profitable before expiration. Time value is highest for at-the-money options with long time horizons and high implied volatility. It decays progressively as expiration approaches (measured by Theta) and reaches zero at the moment of expiration.
- ATM options: Highest time value because uncertainty about ITM/OTM is greatest
- Deep ITM options: Low time value relative to intrinsic, high total premium
- Deep OTM options: Low time value in absolute terms, but 100% of premium is time value
- Long-dated options: More time value because more time for favorable price movement
- High IV options: More time value reflecting greater expected price movement
How to Evaluate If a Premium Is Fair
Always use the mid-point of the bid and ask prices for premium analysis, not just the ask price. Wide bid-ask spreads can make options appear more expensive than they are. Liquid options (SPY, QQQ, AAPL) have tight spreads of $0.01-$0.05, while illiquid options may have spreads of $0.20-$0.50 or more.
Upcoming ex-dividend dates reduce call premiums and increase put premiums because the stock price typically drops by the dividend amount on the ex-date. If a stock pays a $1 quarterly dividend, call premiums will be approximately $1 lower than they would be without the dividend, all else equal.