IV, Skew, and Term Structure: Read the Option Surface
Separate implied volatility from direction, compare strikes and expirations consistently, and understand event premiums and quote-quality limits.
By OrderMap Research4 min read
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One IV number cannot describe a whole chain
Implied volatility is the volatility input that reconciles an option-pricing model with an observed option price, given the other inputs. Different strikes and expirations can have different implied volatilities. The collection is often described as a volatility surface. It reflects prices under a model, rather than a direct measurement of tomorrow's realized movement.
Skew describes variation across strikes for a comparable expiration. Term structure describes variation across expirations at a comparable moneyness or delta. Mixing these axes can produce misleading comparisons. A far-out-of-the-money short-dated put and an at-the-money long-dated call differ in more than one way.
The OIC overview of volatility skew provides the strike-based definition. The workflow below is a practical framework for comparing observations consistently, rather than a promise that the surface predicts direction.
IV concerns magnitude, with important qualifications
Higher implied volatility generally raises the modeled value of a plain long call or put when other inputs are held constant. It does not by itself predict whether the underlying rises or falls. A long option can lose value despite a favorable underlying move if volatility falls or time decay dominates.
Think of an invented earnings example: a stock rises from 100 to 102 after a release, but a call bought at an expensive pre-event premium falls in value. The directional view was favorable, yet the realized movement and remaining uncertainty did not justify the premium paid. The exact result depends on strike, expiry, and the full repricing.
| Comparison | Keep consistent | What can go wrong |
|---|---|---|
| Skew through time | Expiry, delta or moneyness, quote quality | Spot movement changes which strike is comparable |
| Term structure |