What are the options Greeks?

Short answer

The Greeks measure how an option’s price reacts to change. Delta is sensitivity to the stock price, gamma is how fast delta changes, theta is daily time decay and vega is sensitivity to implied volatility. Together they tell you what can make or lose money on a position.

SPY gamma levels, live

As of Oct 16, 7:49 PM ET

The four Greeks at a glance

Delta: about how much the option moves for a $1 move in the stock. A 0.50 delta call gains roughly $0.50.
Gamma: how much delta changes for a $1 move. Highest for at-the-money options close to expiry.
Theta: how much value the option loses per day if nothing else changes. Accelerates in the final weeks.
Vega: how much the option moves for a 1-point change in implied volatility.

How traders use them

Buyers want delta and vega working for them and keep theta small by buying more time. Sellers collect theta but carry gamma risk — a sharp move can hurt quickly. Summing the Greeks across positions shows your total exposure.

Common questions

Which Greek matters most?

Delta for direction, theta for anyone holding options over time. Near expiration, gamma becomes the dominant risk.

Is delta the probability an option expires in the money?

Roughly, as a rule of thumb. A 0.30 delta option has about a 30% market-implied chance, but it is an approximation.

Do the Greeks change?

Constantly — with price, time and volatility. Broker platforms recalculate them live.

Go deeper with Rebel Intel

Explain the Greeks on an NVDA call I am looking at Show me the gamma exposure chart for SPY What is theta decay on a 30-day option?

Educational only, not investment advice. Options involve risk and are not suitable for all investors. See how Intel is reviewed.