Option Greeks are risk sensitivities, not promises.

Delta, gamma, theta and vega describe how an option's theoretical value responds to changes in important inputs. They help describe exposure; they do not predict the future.

Delta

Delta estimates the option-price sensitivity to a small move in the underlying, all else equal. Traders also use delta as a rough strike-selection and directional-exposure tool.

Gamma

Gamma describes how quickly delta changes as the underlying moves. Gamma generally becomes more important as expiration approaches, especially near the strike.

Theta

Theta estimates sensitivity to the passage of time. Short-option positions often benefit from time decay when other inputs are unchanged, but adverse price and volatility moves can overwhelm theta.

Vega

Vega estimates sensitivity to changes in implied volatility. A short-premium portfolio can therefore be exposed not only to price movement but also to volatility expansion.

Read the Greeks together

No Greek should be used in isolation. DTE, moneyness, implied volatility, event risk and portfolio-level exposures all change what the numbers mean in practice.

Learn the complete options framework

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