The Invisible Hand: Market Maker Hedging
When you buy a call option, somebody sells it to you. More often than not, that seller is a market maker - a firm that provides liquidity by taking the other side of your trade. Market makers don't want directional risk; they want the bid-ask spread. To stay neutral, they delta-hedge by buying or selling the underlying stock.
What Is Gamma?
Gamma measures how fast an option's delta changes as the stock price moves. When a market maker is short gamma (they sold options), their hedge adjustments amplify price moves - they buy more stock as it rises and sell more as it falls. When they're long gamma, their hedging dampens moves - they sell into rallies and buy dips.
Positive vs. Negative Gamma Zones
Positive gamma: Market makers are net long gamma. Their hedging stabilizes price - tighter ranges, "pinning" near high-gamma strikes. Scalping and range-bound strategies thrive here.
Negative gamma: Market makers are net short gamma. Their hedging amplifies moves - selling begets more selling, buying begets more buying. Breakouts accelerate and trends extend. Momentum strategies work best here.
What Is GEX?
Gamma Exposure (GEX) quantifies the total gamma market makers must hedge across all strikes and expirations. By mapping GEX to each strike, you get a heatmap of where dealer hedging creates mechanical support, resistance, and volatility.
The strike with the highest absolute GEX is the Anchor Point - a magnet that pulls price toward it. Secondary high-GEX strikes create Defense Lines that act as support/resistance. The price where GEX flips from positive to negative is the GEX Flip Point - cross it and the market regime changes.
See It Live with DealerEdge
Trade Echo's DealerEdge maps GEX across every strike for SPX, NDX, SPY, and QQQ in real time, highlights Anchor Points and Defense Lines, and shows the current gamma regime with a 1-5 GEX Rating - so you always know what type of market you're trading in.