Implied Volatility Explained: The Most Important Number in Options

What Is Implied Volatility?

Implied volatility (IV) is the market's forecast of how much a stock will move over a given period. It's "implied" because it's derived backwards from option prices — if options are expensive, IV is high (market expects big moves). If options are cheap, IV is low.

IV in Plain English

If a stock's IV is 30%, the market expects the stock to move roughly ±30% over the next year. On a daily basis, that's about ±1.9%. For a $100 stock, the market expects a daily range of about $98-$102.

IV Rank: The Most Useful Metric

Raw IV numbers are meaningless without context. NVDA might have 50% IV normally, while KO might have 15%. That's why IV rank exists:

**IV Rank** = (Current IV - 52-week Low IV) / (52-week High IV - 52-week Low IV) × 100

• IV rank 0: IV is at its 52-week low (options are cheap relative to history)
• IV rank 100: IV is at its 52-week high (options are expensive relative to history)
• IV rank 50: IV is in the middle of its historical range

How to Trade Volatility

When IV Rank is High (>60): Sell Premium - Iron condors, credit spreads, covered calls - You're collecting expensive premium that is likely to deflate - Time decay (theta) works in your favor - Best in range-bound markets

When IV Rank is Low (<20): Buy Options - Long calls, long puts, straddles - Options are cheap relative to history - A volatility expansion will increase your option's value even without a stock move - Best before catalysts (earnings, FDA decisions)

The IV Crush Trade Before earnings, IV expands as uncertainty rises. After earnings, IV collapses (IV crush). Strategies: - **Sell premium before earnings**: Profit from IV crush (high win rate, limited reward) - **Buy premium only when expected move is mispriced**: AI compares options pricing to historical moves

Common Mistakes

1. Buying high-IV options before earnings — : Even if you get the direction right, IV crush can destroy your position
2. Ignoring IV when buying options — : Paying 50% IV for a stock that normally has 25% IV means you're overpaying
3. Not considering IV rank — : A stock with 40% IV might have high IV rank (if it normally has 20%) or low IV rank (if it normally has 60%)