title: What Is Gamma Exposure (GEX)? description: Gamma exposure (GEX) measures how market makers' hedging flows move as the price changes. Learn what gamma exposure is, how to read a GEX chart, and how GEX by strike reveals support and resistance. date: 2026-08-03 category: Options Market Structure related: [gamma-flip, dealer-positioning, vanna]
What Is Gamma Exposure (GEX)?
Gamma exposure (GEX) measures how options market makers must hedge their positions as the underlying price moves. It is one of the most important concepts in modern market structure because it directly predicts the flow that drives price.
Gamma exposure explained
Gamma is the second-order Greek that measures how delta changes as the price moves. Market makers are typically short premium — meaning they sell options to their clients. Because of that, their delta hedging creates mechanical, price-dependent flow.
GEX aggregates that flow across every strike. It tells you, at any given price level, whether dealers are buying or selling the underlying to stay hedged.
Positive vs. negative GEX
- Positive GEX — market makers buy weakness and sell strength to stay hedged. This dampens volatility and draws price back toward open interest concentrations. Rallies get sold, dips get bought.
- Negative GEX — market makers are forced to sell into weakness and buy into strength, amplifying directional moves. A small breakout can become a violent trend.
How to read a GEX chart
A GEX chart plots net dealer gamma across price. Read it as a map of hedging pressure:
- Zero line — where the aggregate gamma flips sign. This is the GEX flip line, the most important level on the chart.
- Positive GEX walls — large bars above the zero line. These act as magnets: expect price to stall or reverse here.
- Negative GEX pockets — bars below the zero line. These act as accelerators: expect fast, trending moves through them.
- The bars' width — the scale of dealer positioning at that level. Bigger bars mean more mechanical flow waiting to fire.
The chart is read left to right in time and up and down in price, exactly like a volume profile — except instead of historical volume, it shows future hedging flow.
Gamma exposure by strike
GEX by strike is where the predictive value lives. Each strike holds a specific amount of open interest, and each option contributes delta that must be hedged:
- Strikes with heavy call open interest above price → dealers hold long deltas there → selling pressure above (cap).
- Strikes with heavy put open interest below price → dealers hold short deltas there → buying pressure below (floor).
- The strike where net GEX crosses zero is your flip line — a level where the entire dealer book changes character.
Watch the strike closest to the current price with the largest GEX reading. That is the level where the next meaningful reaction is most likely to occur.
Why traders watch GEX
GEX levels — especially the GEX flip lines — act as self-fulfilling support and resistance. When price approaches a large positive GEX wall, expect the move to stall. When the market is deep in negative gamma, expect fast, trending conditions.
Related terms
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