Gamma Exposure (GEX)
Market maker hedging pressure and volatility regimes
Gamma Exposure (GEX) estimates aggregate gamma positioning and provides context for possible market-maker hedging behavior and volatility regimes.
What is GEX?
Gamma Exposure (GEX) represents the dollar amount of stock market makers must buy or sell to remain delta-neutral when the underlying moves 1%.
Units: Measured in millions of dollars
Sign Convention:
- Positive GEX: Market makers are long gamma (short options to customers)
- Negative GEX: Market makers are short gamma (long options from customers)
GEX Regimes
| Regime | Dealer Behavior | Market Impact |
|---|---|---|
| Positive GEX | Sell rallies, buy dips | Suppressed volatility, mean reversion |
| Negative GEX | Buy rallies, sell dips | Amplified volatility, trending moves |
Key Levels
| Level | Description | Market Impact |
|---|---|---|
| Call Wall | Highest positive GEX strike above current price | May act as resistance if hedging flows matter |
| Put Wall | Highest negative GEX strike below current price | May act as support if hedging flows matter |
| Zero Gamma Level | Price where GEX flips from positive to negative | Possible volatility-regime inflection point |
| Gamma Flip Strike | Alternative term for zero gamma level | Above = suppressed vol, Below = amplified vol |
Strength Factors:
- Larger GEX magnitude = stronger effect
- Closer to expiration = stronger effect (gamma peaks at expiration)
- Higher open interest = more persistent level
Reading the Chart
The GEX chart shows gamma exposure at each strike:
- Tall bars: Major hedging levels (price magnets)
- Zero crossing: Volatility regime change point
- Current price line: Reference for positioning
When GEX Matters Most
| Event | GEX Impact | Trading Implication |
|---|---|---|
| Options Expiration (OpEx) | Large GEX expires, regime can shift dramatically | Expect volatility changes post-expiration |
| Earnings | Individual stock GEX changes rapidly | Pre-earnings: high GEX, Post-earnings: GEX collapse |
| Fed Events | Index-level GEX positioning affects SPY/QQQ | Watch for gamma squeezes around FOMC |
| 0-2 DTE | Gamma effect strongest in final days | Pin effect most powerful |
| High IV Events | Gamma increases with volatility | GEX levels become more significant |
Time Decay: Gamma is highest ATM and peaks as expiration approaches. GEX analysis is most relevant for 0-30 DTE options.
Key Takeaways
- Positive GEX often points to more range-bound, lower-volatility conditions
- Negative GEX often points to more trend-prone, higher-volatility conditions
- Call/put walls (peaks in the GEX bars) can become price magnets or barriers
- Zero gamma level is a possible volatility trigger
- Combine with price action and your own levels
Note: GEX shows current positioning, not predictions. Past GEX patterns may not repeat. Use alongside other analysis and always do your own research.
