Volatility Skew
Volatility skew is the pattern where different strikes carry different implied volatility. Learn why downside puts usually cost more, and what the skew tells you.
Volatility skew is the pattern where options at different strikes carry different implied volatility, even on the same stock and the same expiration. In plain terms, the market charges a different storm premium depending on which strike you look at.
If every strike had the same IV, there would be no skew. But they rarely do, and the tilt tells you where the market's fear is concentrated. Let me show you the shape.
The Insurance Is Pricier
Think about home insurance. A policy against a total loss, the disaster nobody expects but everyone dreads, costs more per dollar of coverage than a policy for a minor mishap. People pay up for protection against the scary tail.
Options work the same way. On most stocks, out-of-the-money puts carry higher implied volatility than out-of-the-money calls. Investors are willing to pay a fat premium for downside protection, because crashes happen fast and hurt badly. That extra demand lifts the IV on the downside strikes, tilting the curve. This lopsided tilt is the classic equity skew.
Why the Tilt Exists
Skew is really the market pricing in the way stocks actually move. Stocks tend to grind up slowly and crash down quickly. A sudden 20% drop is far more common than a sudden 20% spike.
Because the downside is more violent, protection against it is in constant demand. Portfolio managers buy downside puts as insurance, and that steady buying keeps the IV on those strikes elevated. The upside, by contrast, does not inspire the same panic buying, so its IV sits lower. The result is a curve that leans, not a flat line.
When the skew steepens, it is a sign the market is growing more afraid of a downside move. A flattening skew suggests that fear is easing.
Why Traders Watch It
Skew is a map of fear, and it shapes real decisions.
For sellers, those fat downside puts are attractive premium. Selling a cash-secured put on a stock with steep skew means collecting the extra storm premium the market is paying for protection.
For spread traders, skew changes which combinations are cheap or rich. A bull put spread is priced partly by the skew between its two strikes, and downside insurance like a protective put costs more precisely because of it.
Reading the skew keeps you from assuming every strike is priced off the same volatility, when in fact the market is quietly charging more for fear.
- Volatility skew is different IV at different strikes.
- On stocks, downside puts usually carry higher IV.
- It exists because stocks crash faster than they climb.
- A steepening skew signals rising fear of a drop.
Pop Quiz
Three quick questions to see what stuck. Pick an answer and the explanation shows up right away.
What is volatility skew?
Skew is the pattern of IV varying across strikes on the same stock and expiration.
On most stocks, which options carry the higher implied volatility?
Investors pay up for crash protection, so downside puts carry elevated IV, creating the tilt.
Why does equity skew exist?
Violent downside moves drive steady demand for put protection, lifting IV on the downside strikes.
Bottom Line
Volatility skew is the market admitting that not all strikes are equally scary. Downside protection costs more because crashes are fast and frightening, so the IV curve tilts toward the puts. Read the tilt and you can see where fear is priced in.
For a trader, skew turns a flat assumption into a live signal: it tells you which options are richly priced, which are cheap, and how nervous the market really is about a drop.
Keep going: see the symmetric cousin in the volatility smile, the full map across strikes and expirations in the volatility surface, and the forecast underneath it all in implied volatility.