What is Vega? Volatility Sensitivity Explained
Master vega, the Greek that connects your options position to implied volatility. Learn how IV changes affect your P&L and how to position for volatility events.
What is Vega?
Vega measures how much an option's price changes for a 1 percentage point change in implied volatility. It tells you your exposure to volatility shifts, which is critical around earnings and market events.
Vega is highest for ATM, longer-dated options. Option buyers are long vega (profit from IV increases), while sellers are short vega (profit from IV decreases). Vega is the key Greek for earnings trades.
TL;DR - Quick Answer
Vega = price change per 1% IV move. A vega of 0.10 means the option gains $10/contract if IV rises 1%. Long options = long vega (benefit from IV increase). Short options = short vega (benefit from IV decrease). Longest-dated ATM options have highest vega. Critical around earnings: IV can change 20-40 points, causing $200-400+ P&L swings per contract from vega alone.
What is Vega?
Vega measures your option's sensitivity to changes in implied volatility (IV). When IV rises, all options become more expensive (higher vega = bigger impact). When IV falls, all options become cheaper. Vega tells you exactly how much your position gains or loses for each 1% change in IV.
Example: You hold an AAPL call with a vega of 0.15. If AAPL's IV rises from 30% to 35% (a 5-point increase), your option gains $0.75 ($0.15 x 5 points), or $75 per contract. If IV drops 5 points instead, you lose $75—regardless of whether the stock moved.
Key Vega Characteristics
ATM options have the highest vega: They're most sensitive to IV changes because ATM options have the most time value (which is driven by volatility).
Longer-dated options have higher vega: A 90-day option has roughly 3x the vega of a 10-day option. This is why LEAPS are most affected by IV changes and short-dated options are least affected.
Vega decreases as expiration approaches: Near-expiration options barely react to IV changes because there's little time value left to expand or contract.
Vega Around Earnings: Why It Matters
Earnings trades are fundamentally vega trades. Before earnings, IV rises (options become expensive). After earnings, IV collapses (IV crush). The magnitude of this IV change, multiplied by your vega, determines a huge portion of your earnings trade P&L.
Example: Pre-earnings NVDA ATM straddle with vega of 0.25. IV is at 75%. Post-earnings, IV drops to 40% (35-point decline). Vega impact: 0.25 x 35 = $8.75 per share, or $875 per contract in losses from vega alone. The stock would need to move more than $8.75 just to break even on the vega loss.
Key Takeaways
- Vega = option price change per 1% IV move
- Long options = long vega (profit when IV rises)
- Short options = short vega (profit when IV falls)
- ATM, longer-dated options have the highest vega
- Vega is critical around earnings—IV crush can overwhelm directional gains
Related Options Strategies
Implied Volatility Guide
Understand IV before studying vega.
IV Crush
Vega explains why IV crush hurts option buyers.
What is Theta
Theta and vega are the key Greeks for income traders.
Understanding related strategies helps you choose the best approach for your market outlook and risk tolerance. Each strategy has unique characteristics that make it suitable for different market conditions.
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