Vega

Vega measures how much an option price changes for every one-point move in implied volatility. It is the Greek that explains how you can be exactly right about direction and still lose money.

Why Vega Surprises People

Buy calls ahead of an earnings release, watch the stock rise 6%, and still lose money. The cause is vega: implied volatility was inflated before the event and collapsed the moment the uncertainty was resolved. The stock moved your way, but not enough to offset the volatility crush. Checking IV Rank before paying premium ahead of a known catalyst prevents this specific failure.

Where Vega Concentrates

Vega is highest for at-the-money options and grows with time to expiration. A LEAPS can carry several times the vega of a 30-day option at the same strike — which makes long-dated options primarily a bet on volatility as much as on direction. Buying a LEAPS with IV Rank near its highs means a simple normalisation of volatility can cost you more than direction earns.

Managing Vega

Vertical spreads largely neutralise vega because the two legs offset each other — which is exactly why they are the right structure when you have a directional view and no volatility view. Calendars, by contrast, isolate vega deliberately: they are the cleanest way to express a view on volatility with limited directional exposure.

The Variance Risk Premium

Implied volatility persistently trades above the volatility that subsequently materialises. That gap is the variance risk premium, and it is the structural reason systematic premium selling with defined risk has positive expectancy over time — provided you survive the tails, which is where the premium is earned back by the market.