GEX Trading Guide: How to Read and Trade Gamma Exposure for SPY, TSLA, QQQ and More

GEX has become the single most talked-about metric in options market structure. It explains why SPY sticks to $580 for three days straight and then drops $15 in an hour. It explains why TSLA gaps through resistance like it doesn't exist while AAPL pins to the penny on expiry Friday. Most GEX content stops at the basics: positive GEX good, negative GEX bad. That's not enough to trade on. This guide goes deeper: strike-level data, the full dealer exposure stack, and seven concrete trade setups with code. What Is GEX and Why Does It Move Markets? When you buy a call, a market maker sells it to you. They hedge by buying shares. But as price moves, the option's delta changes. The rate of that change is gamma. Because gamma shifts delta, the dealer must continuously adjust: buying more when price rises, selling when it falls. GEX (gamma exposure) is the total dollar-value of stock that dealers must buy or sell per 1% move in the underlying, aggregated across every open option contract. Posit