Theta

Theta measures the sensitivity of an option's theoretical value to the passage of time, usually expressed as an estimated change over a specified time interval, commonly one day, assuming other relevant factors remain unchanged. Example An option displays: Theta = -0.15 Under the platform's convention, that may indicate an estimated loss of approximately: $0.15 in option value from the passage of one day, all else equal. With a 100 share multiplier, that would correspond to approximately: $15 per contract.