Vega Explained: How IV Moves Option Prices
Vega measures how sensitive an option's price is to changes in implied volatility — the market's forecast of future movement. Unlike delta and theta, vega has nothing to do with the stock moving or time passing; it captures what happens when the market simply re-prices uncertainty. It is the Greek that decides whether an earnings trade wins or gets crushed.
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What vega measures
Vega is the change in an option's price for a one-percentage-point change in implied volatility (IV). An option with a vega of 0.12 gains about $0.12 in value if IV rises from 30% to 31%, and loses about $0.12 if IV falls one point — before any move in the underlying. Because higher volatility means a wider range of possible outcomes, more IV makes every option, call or put, more valuable.
Vega is always positive for a long option and applies equally to calls and puts at the same strike and expiration. It is the bridge between the abstract IV number quoted in the chain and the dollars your position actually gains or loses when volatility shifts.
Long vs short vega, expiration, and maturity
Owning options gives you long, positive vega: you profit when implied volatility rises and lose when it falls. Selling options — credit spreads, iron condors, short strangles — gives you short, negative vega, so you profit as IV declines. Matching your vega to your volatility view is as important as matching delta to your directional view.
Vega is larger for longer-dated options and shrinks as expiration approaches. A LEAPS option has far more vega than a weekly, because a change in expected annualized volatility has many more months to act on a long-dated contract. As an option runs into its final days, its vega collapses toward zero and theta and gamma dominate instead.
Vega around earnings and IV crush
Before a scheduled event like earnings, implied volatility rises as uncertainty builds, inflating the vega-driven portion of every option's price. Because you are long vega when you buy those options, you are paying up for that elevated IV — and a straddle or long call bought into earnings can lose money even if the stock moves, if the move is smaller than the premium already priced in.
The moment earnings are released, the uncertainty resolves and IV collapses — the so-called IV crush. That sudden drop hits long-vega positions hard and rewards short-vega positions. This is why premium sellers often target the pre-earnings IV spike, while buyers need a move large enough to overcome the vega loss that follows.
- Vega is the price change per one-point change in implied volatility, before any stock move.
- Long options are positive vega (gain when IV rises); short options are negative vega (gain when IV falls).
- Vega is larger for longer-dated options and shrinks toward zero as expiration nears.
- IV rises into earnings and crushes afterward, which is why long-vega earnings buyers can lose even on a real move.
Frequently asked questions
Does vega apply to calls and puts equally?
Yes. At the same strike and expiration, calls and puts share the same vega — higher implied volatility raises the value of both.
Why does a longer-dated option have more vega?
Implied volatility is annualized, so a change in it has more time to affect a long-dated option's range of outcomes, giving it greater sensitivity than a short-dated one.
How do I avoid getting hurt by IV crush?
Be aware of earnings dates, avoid buying inflated long-vega options right before them, or use short-vega or vega-neutral structures like spreads to reduce exposure to the post-event volatility drop.
Implied Volatility ExplainedUnderstanding the Option GreeksTrading Options Around Earnings
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