Gamma Exposure (also known as GEX) is one of the most powerful and underrated tools for options traders. If you want to understand how major price levels form — and how to trade around volatility — this is essential information.

What is Gamma?

In options trading, Gamma measures the rate of change of Delta, which is how much an option’s price changes based on the underlying asset.

Think of it like this:

Delta = speed

Gamma = acceleration

When gamma is high, it means options prices are sensitive to even small price changes — which forces market makers to react quickly.

What is Gamma Exposure (GEX)?

Gamma Exposure aggregates all the gamma from open call and put positions at each strike price. This shows where market makers are likely to buy or sell stock to stay hedged as price moves.

• When Gamma Exposure is positive, dealers hedge against the move — creating stability.
• When Gamma Exposure is negative, they hedge with the move — adding fuel to rallies or crashes. 

This explains why certain price levels seem to “magnetize” the market or trigger explosive momentum - like that epic “gamma squeeze” in GameStop (GME) a few years back.

How to Read the Gamma Exposure Tool on Barchart

Our Gamma Exposure page offers 3 key views:

1. Gamma Exposure by Strike: See where gamma is concentrated — these are key battlegrounds for price.
2. Call/Put Open Interest by Strike: Understand the volume behind the gamma. This gives context to where traders are positioned.
3. Total Net Gamma Exposure by Expiration Date: View how gamma will evolve leading into major expirations (like earnings).

Use these charts to predict:

• Support & resistance zones
• Volatility crush or expansion
• Pin risk levels during expiration week

Example: Using Gamma on SPY

Let's say the S&P 500 SPDR ETF (SPY) is approaching a level with heavy negative gamma at 585. This means as prices climb toward 585, dealers may be buying more stock, pushing the price up.

If SPY breaks above 585, that momentum can accelerate — creating a short-term rally.

On the flip side, if a large positive gamma cluster sits at 600, it might act like a ceiling — capping price moves.

When Should You Use Gamma Exposure?

• During OPEX (options expiration week)
• Before major earnings or Fed decisions
• In high-volatility environments
• When stocks are trending fast or reversing sharply

Watch: Gamma Exposure Explained on YouTube:

Keep Learning

For a deeper dive on gamma exposure, watch this popular explainer. And to explore even more tools, strategies, and indicators, check out our Options Learning Center.