Vega measures how much an option’s price changes for every 1 percentage point change in implied volatility (IV). Unlike the other Greeks named after actual Greek letters, vega is not a Greek letter, but it’s grouped with them. Higher vega means the option is more sensitive to volatility changes. Long options have positive vega; short options have negative vega.
- Measures price change per 1% IV change
- Long options: positive vega (benefit from rising IV)
- Highest for ATM options with more time
How Vega Works
Vega shows volatility sensitivity:
Vega Example:
Option Premium: $5.00
Vega: 0.15
Current IV: 30%
If IV rises to 35% (+5%):
Premium = $5.00 + (5 × $0.15) = $5.75
If IV falls to 25% (-5%):
Premium = $5.00 - (5 × $0.15) = $4.25
Even without stock movement,
IV changes move option prices!
Quick Reference: Vega Values
| Option Type | Vega Level | Reason |
|---|---|---|
| Long-dated ATM | Highest | Most time for volatility to matter |
| Short-dated ATM | Moderate | Less time |
| Deep ITM | Lower | Less uncertainty |
| Deep OTM | Lower | Less uncertainty |
| Weeklies | Very Low | Almost no vega exposure |
Example: Vega and Earnings
IV Crush After Earnings:
| Period | IV | Vega | Premium |
|---|---|---|---|
| Before Earnings | 60% | 0.20 | $8.00 |
| After Earnings | 30% | 0.15 | $2.00 |
| IV Drop | -30% | - | -$6.00 loss |
Stock didn’t move, but IV crush destroyed the premium.
Vega measures how option prices change with volatility. When implied volatility rises, options become more expensive. When IV falls (IV crush), options lose value even if the stock moves your way. ATM options with more time have the highest vega.
Vega and Time
| Days to Expiry | Vega Level |
|---|---|
| 90+ days | High |
| 60 days | Moderate-High |
| 30 days | Moderate |
| 14 days | Low |
| 7 days | Very Low |
Longer-dated options are much more sensitive to IV changes.
Trading Vega
Long Vega (Buying Options)
- Benefits from rising volatility
- Buy before earnings, events
- Risk: IV crush if you hold through event
Short Vega (Selling Options)
- Benefits from falling volatility
- Sell when IV is high
- Profit as IV normalizes
Vega Strategies
Volatility Plays
Buy straddles/strangles before events expecting big moves (and IV rise).
IV Crush Plays
Sell options when IV is elevated, profit as it normalizes.
Calendar Spreads
Long long-dated, short near-dated. Positive vega exposure.
Common Mistakes
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Buying options before earnings – IV crush can negate correct directional bet.
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Ignoring IV levels – Check if IV is high or low historically before trading.
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Not understanding vega exposure – Know if you’re long or short vega.
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Confusing IV with historical volatility – IV is forward-looking expectation.
How JournalPlus Tracks Vega
JournalPlus tracks vega exposure and IV levels at entry, helping you understand your volatility risk and identify when IV crush hurt your trades.
