Options prices are determined by six factors: the underlying stock price, the strike price, time until expiration, implied volatility, interest rates, and expected dividends. Of these, implied volatility is the one that surprises most beginners — it's the reason an option can lose value even when the stock moves in your favor.

Factor 1: Stock Price

The most intuitive driver. When a stock rises, call prices increase and put prices decrease. When a stock falls, puts become more expensive and calls get cheaper.

The rate of change is measured by delta. An ATM call has a delta of roughly 0.50, meaning it gains $0.50 for every $1 the stock rises. A deep ITM call might have 0.90 delta — nearly dollar-for-dollar with the stock.

Factor 2: Strike Price

The relationship between strike and stock price determines intrinsic value. A $100 call on a $110 stock has $10 of built-in value. A $120 call has zero intrinsic value — it's all time and hope.

Strike price is fixed when you open the trade. You choose it; you can't change it later.

Factor 3: Time to Expiration

More time = more expensive. A 90-day option costs significantly more than a 30-day option at the same strike. This makes sense — there's more time for the stock to move in your favor.

Time decay (theta) is non-linear. An option loses time value slowly early on, then rapidly as expiration approaches. A 30-day option might lose 3% of its value per day. In the final week, that accelerates to 7–10% per day.

| Days to Expiration | Approximate Time Value Remaining | 90 days100% 60 days82% 30 days58% 14 days39% 7 days28% | 1 day | 10% |

This is why buying short-dated options is dangerous — you're fighting rapid decay. And it's why selling short-dated options is popular — you benefit from that same rapid decay.

Factor 4: Implied Volatility (IV)

Implied volatility reflects the market's expectation of future price movement. Higher IV = more expensive options. Lower IV = cheaper options. Both calls and puts get more expensive when IV rises.

Practical example: AAPL normally has an IV of 25%. Before earnings, IV might spike to 50%. That $5.00 call suddenly costs $8.00 — not because the stock moved, but because the market expects a bigger swing.

After earnings, IV collapses back to 25%. Even if the stock moved in your direction, the option might lose value from the "IV crush." This catches countless beginners off guard.

How to use IV:

  • Buy options when IV is low (cheap premiums) and you expect a volatility expansion
  • Sell options when IV is high (expensive premiums) and you expect a volatility contraction
  • Compare current IV to the stock's IV rank or IV percentile to gauge relative cheapness or richness

    • Factor 5: Interest Rates

    Higher rates slightly increase call premiums and decrease put premiums. The effect is minor for short-dated options but noticeable on LEAPS expiring a year or more out. Most retail traders can ignore this factor for monthly options.

    Factor 6: Dividends

    Expected dividends decrease call premiums and increase put premiums. On the ex-dividend date, the stock drops by the dividend amount. This matters most for high-dividend stocks with short-dated options.

    Putting It All Together

    The Black-Scholes model combines all six factors into a theoretical price. But the market price can deviate when supply and demand are unbalanced. Heavy call buying before an FDA decision can push premiums above fair value. That's when sellers profit — the core principle behind income strategies featured in OptionsPilot.

    The One Factor You Control

    You can't control stock price, volatility, rates, or dividends. But you control which strike price and expiration date you choose. That choice determines your risk profile, probability of profit, and exposure to each pricing factor.