What Is GEX (Gamma Exposure)?
Gamma Exposure (GEX) measures how much options market makers (dealers) need to buy or sell the underlying stock to stay hedged as price moves. This dealer hedging activity is one of the most powerful forces driving intraday price action, yet most retail traders have never heard of it.
When you buy a call option, the dealer who sold it to you must hedge by buying shares of the stock. As the stock price moves, the dealer must continuously adjust that hedge. GEX quantifies exactly how much buying or selling dealers need to do at each price level.
Positive vs Negative Gamma: The Key Concept
Positive Gamma (Dampening)
When net GEX is positive, dealers must buy dips and sell rips to stay hedged. This creates a dampening effect that compresses volatility and keeps prices range-bound. Positive gamma environments are characterized by low VIX and mean-reverting price action.
Negative Gamma (Amplifying)
When net GEX is negative, dealers must sell dips and buy rips. This amplifies moves in both directions, creating cascading sell-offs or explosive rallies. Negative gamma is when the biggest intraday swings happen.
Understanding whether the market is in positive or negative gamma is arguably the single most important piece of information for day traders. It tells you whether to expect mean reversion or trend continuation.
Call Walls, Put Walls & the GEX Flip Point
Call Walls
The call wall is the strike price with the highest positive gamma exposure from call options. It acts as a magnetic ceiling for price. In positive gamma environments, the stock will often gravitate toward the call wall and struggle to break above it, as dealers sell into rallies at that level.
Put Walls
The put wall is the strike with the highest gamma exposure from put options. It serves as a magnetic floor. Dealers buy the stock as it approaches the put wall to stay hedged, creating support.
GEX Flip Point
The GEX flip point is the price level where dealer positioning transitions from positive to negative gamma. Above the flip point, dealers dampen moves. Below it, they amplify them. When a stock breaks below its GEX flip point, expect increased volatility and potential cascading sell-offs.
| Metric | SPY | QQQ | NVDA | TSLA |
|---|---|---|---|---|
| Net GEX | +$4.2B | +$1.8B | +$890M | -$320M |
| Call Wall | $535 | $490 | $950 | $200 |
| Put Wall | $520 | $475 | $880 | $170 |
| GEX Flip | $525 | $480 | $910 | $185 |
| Regime | Positive | Positive | Positive | Negative |
Interactive bar chart showing gamma exposure at each strike price, with call wall, put wall, GEX flip point markers, spot price indicator, and positive/negative gamma zones color-coded green/red
Directional GEX (dGEX): Our Proprietary Edge
Standard GEX tells you the magnitude of dealer hedging at each strike. Our directional GEX (dGEX) goes further by decomposing the exposure into the directional impact: how much will dealers need to buy vs sell if the stock moves up $1 vs down $1?
This asymmetry is crucial. A stock may have high positive GEX overall, but if the dGEX is skewed heavily to one side, it means dealers will react very differently to an up-move vs a down-move. This asymmetry creates predictable price magnets and zones of acceleration.
How Dealers Move the Market
Options dealers are not directional traders. They do not care whether the stock goes up or down. They profit from the bid-ask spread on options and must continuously hedge their exposure. But this hedging creates massive, predictable flows:
- Daily gamma hedging: Dealers adjust positions throughout the day, creating mean reversion in positive gamma and trend extension in negative gamma.
- OPEX pinning: As options expire, gamma concentrates at popular strikes. Dealers' hedging forces the stock to "pin" near the strike with the most open interest.
- Charm decay: As options lose time value (especially overnight), dealers must adjust hedges. This creates predictable opening gaps.
- Vanna effects: When implied volatility drops, dealers must buy stock to hedge. When IV spikes, they must sell. This creates the "VIX down, market up" relationship.
How to Use GEX in Your Trading
GEX data is most actionable when combined with traditional technical analysis. Use the call wall as a profit target for longs, the put wall as support for buying dips, and the GEX flip point as a risk management level. When a stock is in negative gamma, tighten stops and expect wider swings.
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Frequently Asked Questions
GEX measures the total gamma exposure of options market makers at each strike price. It quantifies how much dealers need to buy or sell the underlying stock to maintain their hedges as price moves. This dealer hedging creates predictable price behavior including support/resistance levels and volatility regimes.
Negative gamma means options dealers must sell when the stock drops and buy when it rises, amplifying moves in both directions. This creates higher volatility, larger intraday swings, and trending (rather than mean-reverting) price action. Most major sell-offs occur when the market is in negative gamma territory.
A GEX chart shows gamma exposure at each strike price as bars. Tall green bars above the zero line represent call-side gamma (resistance); red bars below represent put-side gamma (support). The tallest call bar is the call wall (ceiling), tallest put bar is the put wall (floor), and the crossover point is the GEX flip where positive gamma transitions to negative.
Call walls are strike prices with the highest concentration of call option gamma. They act as magnetic ceilings because dealers sell stock as price approaches. Put walls are strikes with the highest put gamma and act as floors because dealers buy stock as price approaches. These levels often provide reliable short-term support and resistance.