Gamma Exposure (GEX), Visualized

What is gamma exposure?

When you buy an option, a market maker usually takes the other side, and market makers hedge: they buy or sell stock to stay directionally neutral as price moves. Gamma measures how fast their required hedge changes. Gamma exposure, or GEX, aggregates that across every contract’s open interest to estimate how much stock dealers must buy or sell as price moves through each level.

Why it matters: dealer hedging is mechanical and enormous. When dealers are long gamma, they sell into rallies and buy dips, dampening moves and pinning price near heavy strikes. When they are short gamma, hedging works in reverse and amplifies moves in both directions. Knowing which regime a ticker is in, and where the heavy strikes sit, explains a lot of otherwise puzzling price behavior around expiration weeks.

The GEX heatmap

Robinflow renders gamma exposure as a heatmap across strike and expiration: gold for positive-gamma magnets that tend to attract and pin price, purple for negative-gamma zones where moves can accelerate, with the live spot price marked against the grid. Call walls and put walls, the strikes with the heaviest concentrations, stand out at a glance instead of hiding in a table.

A date picker with a trading calendar lets you step back through prior sessions to see how positioning built up before big moves, and the heatmap covers every optionable ticker, not just the index products most GEX tools stop at.

How traders use GEX

Common uses: identifying pin candidates into expiration, locating strikes likely to act as support or resistance because of hedging pressure, judging whether a breakout is fighting dealer flows or riding them, and sizing risk differently in negative-gamma regimes where moves run further than usual. GEX is an estimate built on open interest and standard dealer-positioning assumptions, and Robinflow presents it as context alongside options flow and dark pool levels rather than a standalone oracle.