What Is GEX?
GEX measures total gamma options market makers hold across all strikes — quantifying how much dealers buy or sell to hedge as price moves. Long gamma (positive GEX) means dealers absorb volatility; short gamma (negative) means they amplify moves.
The Gamma Flip
The flip is the price level where net dealer GEX crosses from positive to negative. Above it: range-bound, low-vol conditions. Below it: trending, higher-vol. Near expiration, the flip becomes an especially powerful pivot as gamma concentration peaks.
Call Wall vs. Put Wall
The call wall is the strike with the highest call gamma — acts as magnetic resistance as dealers must sell into it. The put wall is the mirror support. Price often pins between these walls near expiration in positive gamma environments.
Using GEX in Trading
Before every trade check: (1) Positive or negative gamma regime? (2) Where is the flip vs. current price? (3) Are we near a call/put wall? In positive gamma, sell premium near walls. In negative gamma, buy directional options near the flip for amplified moves.