Options Greeks
Understand delta, gamma, theta, vega, and the limits of simplified Greek measurements.
Greeks describe sensitivities
Options Greeks are model-based measurements of how an option price may respond when one input changes while other inputs are held constant. Real markets move multiple inputs at once, so Greeks are guides—not guarantees.
Delta
Estimates sensitivity to a one-dollar move in the underlying and is sometimes used as a rough probability proxy, though that interpretation has limits.
Gamma
Estimates how delta changes as the underlying price changes.
Theta
Estimates the effect of time passing. Time decay is not perfectly linear and often accelerates near expiration.
Vega
Estimates sensitivity to changes in implied volatility.
Rho
Estimates sensitivity to changes in interest rates.