Gamma Exposure (GEX)

TL;DR: Gamma exposure (GEX) reveals where market maker hedging will either pin a stock's price in place or amplify its moves.

Gamma exposure, or GEX, measures the aggregate gamma positioned by market makers across all option strikes and expirations for a given stock or index. Gamma itself is the rate of change of delta — it tells you how quickly an option's directional sensitivity changes as the stock moves. GEX takes this concept to the market level, revealing how market maker hedging activity will influence stock price behavior.

When market makers have high positive GEX at a specific strike, their hedging activity creates a stabilizing force. As the stock rises, they sell shares to stay delta neutral; as it falls, they buy. This creates a "pinning" effect that tends to keep the stock near that strike, especially approaching expiration. Conversely, when aggregate GEX is negative, market maker hedging amplifies moves — they buy as the stock rises and sell as it falls, creating a feedback loop that increases volatility.

Understanding GEX helps explain seemingly irrational price behavior. Stocks that appear "stuck" at a price near expiration are often being pinned by high positive gamma at that strike. Stocks that seem to accelerate in one direction may be experiencing negative gamma dynamics. Options Pilot tracks open interest walls and gamma risk within the Timing pillar, identifying where significant OI concentrations exist, what the max pain level is, and whether pin probability is high — giving you awareness of the mechanical forces that can override fundamental analysis near expiration. TradeSignals shows put walls and call walls based on gamma exposure data.