Gamma Exposure (GEX) reveals how options market makers are positioned — and how their hedging activity is likely to push or pull the market. Here's what it means and how to use it.
Sample GEX Heatmap — Live version available with Pro
What is Gamma Exposure (GEX)?
Every time a trader buys an options contract, a market maker (dealer) takes the other side and immediately hedges their position by buying or selling shares of the underlying. As the stock price moves, that hedge needs to be adjusted — and those adjustments create real buying and selling pressure in the market.
GEX measures the total dollar value of that hedging activity across all strikes and expirations. It answers a simple question: how much are dealers going to buy or sell for every 1% move in SPY?
When dealers are net long gamma (positive GEX), their hedges work against the market's direction — they sell when it rises and buy when it falls, dampening volatility and pulling price back toward key strikes. When they're net short gamma (negative GEX), they amplify moves instead.
The Four Things to Look At
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King Node
The strike with the highest absolute GEX across all expirations. This is the gravitational center of the market — price tends to be attracted to it when dealers are long gamma, and repelled from it when they're short. It's the single most important level on the heatmap.
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Gatekeeper
The second-largest GEX node. Think of it as the next significant support or resistance after the King. If price breaks through the King Node, the Gatekeeper is often the next level where hedging pressure reasserts itself.
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Gamma Flip
The strike where net GEX crosses from positive to negative (or vice versa). This is the regime change level — above it, dealers are mean-reverting. Below it, they amplify moves. When SPY is near the flip, expect a volatility regime shift.
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Net Regime
The sum of all GEX across every strike and expiration. Positive = dealers are net long gamma market-wide, dampening moves. Negative = dealers are net short gamma, amplifying moves. This is the single-sentence read on overall market structure.
Reading the Colors
Each cell in the heatmap shows the GEX contribution from a single strike + expiration combination. The color tells you direction and intensity at a glance.
Green — Positive GEX (Dealer Long Gamma)
Dealers are net long gamma at this strike. Their hedging is contrarian — they buy dips and sell rips near this level, creating support and resistance. Deeper green means more hedging pressure, stronger magnetic pull on price.
Red — Negative GEX (Dealer Short Gamma)
Dealers are net short gamma here. Their hedging reinforces moves — they buy when price rises and sell when it falls, accelerating momentum. Deep red zones are areas where price tends to move through quickly with conviction.
Common Questions
Does GEX predict direction?
No — GEX tells you about the mechanics of how dealers will hedge, not which way the market will move. It helps you understand whether a move is likely to be dampened or amplified, and which price levels carry the most dealer flow.
Why does the 5m Δ column matter?
GEX is not static — it shifts as options are bought and sold throughout the day. The 5-minute delta shows which strikes are seeing the most change in dealer positioning right now. A King Node that's rapidly gaining GEX is strengthening as a magnet; one that's losing it may be breaking down.
Which expiration matters most?
For intraday trading, the nearest expiration (especially 0DTE on SPY) carries the most gamma and dominates price action. Longer-dated expirations matter more for multi-day swing setups where the gamma effects are more gradual.
How often does the live heatmap update?
The live heatmap refreshes every 5 minutes during market hours. It automatically uses Flow GEX (based on intraday volume) when the market is open — capturing where options activity is concentrated in the current session — and switches to Position GEX (based on open interest) overnight for multi-day context. You can toggle between the two modes at any time.
Free Tool
See the Live GEX Heatmap
Real-time SPY GEX with King Node, Gatekeeper, Gamma Flip, and auto-generated market structure summary. Switches between Flow GEX (intraday volume) and Position GEX (open interest) so you always have the right context. Free for all TraderVoila users.