Gamma Exposure (GEX)
The aggregate Gamma positioning of options market makers — determines how dealer hedging amplifies or dampens SPX price moves.
Gamma Exposure (GEX) measures the total Gamma held by options market makers (dealers) across all SPX strikes and expirations. It reveals whether dealer hedging will amplify or dampen price movements — one of the most powerful predictive tools for intraday SPX behavior.
Positive GEX (dealers are Long Gamma):
- ●Dealers hedge by selling into rallies and buying dips
- ●Creates a "volatility suppression" effect
- ●Price tends to mean-revert — supports Balanced Day classification
- ●Range compression around high-GEX strikes
Negative GEX (dealers are Short Gamma):
- ●Dealers hedge by buying into rallies and selling into dips
- ●Creates a "volatility amplification" effect
- ●Price tends to trend or expand — supports Trend Day/Expansion Day classification
- ●Breakouts accelerate as dealer hedging adds fuel
Key GEX levels:
- ●GEX Flip: The strike price where aggregate dealer Gamma crosses from positive to negative
- ●Max GEX Strike: The strike with the largest absolute Gamma concentration — acts as a "magnet"
- ●0DTE GEX: The same-day expiration component, which becomes the dominant force by mid-session
SPXXL tracks real-time GEX across all expirations and visualizes the Gamma profile on the dashboard. The engine uses GEX positioning as a primary input for session classification and Close Zone projection.
Related Terms
The dealer desks that quote and take the other side of SPX options trades — their delta and Gamma hedging of 0DTE flow is now one of the strongest forces shaping intraday SPX price action.
SPXXL's proprietary projected closing price range for SPX, computed using session classification, Gamma exposure, and intraday momentum.
A volatile session with range expansion beyond normal boundaries — often triggered by macro catalysts or institutional repositioning.
A session where price oscillates around a central value area with no directional conviction — the most common session type for SPX.
The CBOE Volatility Index measuring expected 30-day SPX volatility — the market's "fear gauge" and key input to session classification.
The strike price where the largest dollar amount of SPX option premium expires worthless — a settlement magnet that price often drifts toward into expiration as dealers hedge toward the pin.