How much delta changes for every $1 the stock moves. High at ATM and near expiration, it makes the contract accelerate nonlinearly. Buyers benefit from high gamma, sellers fear it.
Some sources also spell the Arabic term with a different letter. The meaning is the same.
How to read the number
Gamma measures how fast delta changes: how much the contract's delta rises for each $1 the stock moves. Gamma of 0.05 means a delta of 0.50 becomes about 0.55 after the stock rises $1. Gamma peaks at the money and near expiration, and fades the further the strike is or the longer the time left.
Why this number matters
Gamma explains the nonlinearity an option buyer lives with: gains speed up as the move goes their way, and losses slow down when it goes against them. An option seller carries negative gamma, so a big move in either direction hurts. That is why sellers chase quiet markets and fear sudden spikes.
Market gamma, not just your own contract's gamma
When you add up the gamma of every open contract on an index or stock, market maker positioning shows. Positive total gamma means their hedging sells into rallies and buys dips, which dampens volatility. Negative gamma means their hedging chases price, which amplifies the move. This is the number the GEX dashboard shows on the platform.
Hypothetical example
An at-the-money call has delta 0.50 and gamma 0.06. The stock rises $2: the new delta is about 0.62, so the contract is now more sensitive to the next move than it was.
Common mistake
Don't ignore gamma near expiration. In the last days, the gamma of at-the-money contracts swells until their delta swings between 0.2 and 0.8 in a single session. The contract becomes a fast-moving instrument in both directions.
Where to see it on the platform
The Gamma dashboard shows Gamma Exposure (Gamma Exposure · GEX) for each covered symbol, with the call and put walls and the Gamma Flip. It updates through the session.
