What is vega? Sensitivity to volatility

Vega tells you how much an option's price changes when implied volatility (IV) moves by one percentage point, holding everything else constant. A vega of 0.08 means a 1-point rise in IV adds about $0.08 per share ($8 per contract) to the option's price.

Unlike delta and gamma, which react to the stock's price, vega reacts to the market's expectation of future movement. It is the greek of fear and calm.

Like gamma, vega peaks for at-the-money options. But it also grows with time to expiration: a 90-day option has much more vega than a 7-day option, because there is more future for volatility to act on.

So the biggest volatility risk lives in longer-dated, at-the-money options, and the smallest in short-dated, far out-of-the-money ones.

When you sell an option, you are 'short vega.' If IV rises after you sell, the option you are short gets more expensive to buy back — a mark-to-market loss, even if the stock has not moved.

Conversely, if IV falls, the option cheapens and you profit. This is why sellers prefer to open positions when IV is already elevated: there is more room for it to fall than to rise.

IV usually inflates going into earnings and collapses right after — the 'IV crush.' A short option held through earnings can gain value quickly from that vega collapse, provided the stock does not gap through your strike.

That is the vega trade-off around events: rich premium and a favorable IV drop on one side, sharp gap risk on the other. Vega explains the reward; delta and gamma explain the danger.

The wheel is naturally short vega, which pairs well with selling when IV rank is high. You collect fat premium and benefit as volatility mean-reverts lower.

Because wheel sellers usually favor 30–45 day, out-of-the-money strikes, their vega is moderate rather than extreme — enough to benefit from falling IV, not so much that a volatility spike alone dominates the position.

Delta and gamma answer 'what if the stock moves?' Theta answers 'what if time passes?' Vega answers 'what if fear changes?' A complete view of a short option needs all four.

For a seller the ideal setup often lines up several greeks at once: sell when IV is high (short vega tailwind), collect accelerating decay (positive theta), at an out-of-the-money strike (manageable delta and gamma).