What is GEX (gamma exposure)?

GEX, or gamma exposure, estimates how much underlying that options dealers must buy or sell to stay hedged for each one-point move in the index. It is derived from options open interest and each strike's gamma. Aggregated across all strikes, GEX maps where dealer hedging pressure concentrates, which is why it predicts support, resistance, and volatility regimes.

What does positive vs negative GEX mean?

Positive net GEX means dealers are net long gamma and hedge against the move — selling rallies and buying dips — which suppresses volatility. Negative net GEX means dealers are net short gamma and hedge with the move — buying rallies and selling dips — which amplifies volatility. The price where net GEX equals zero is the gamma flip, or Zero Gamma level.

How is GEX calculated?

For each strike, GEX is approximately the option's gamma multiplied by open interest, the contract multiplier, and spot price, with a sign convention that assumes dealers are short calls and long puts (or vice versa). Summing the signed contributions across all strikes gives net GEX, and grouping by strike reveals the key levels such as the Call Wall, Put Wall, and Zero Gamma.

Gamma Exposure (GEX) Explained

What GEX is, how it's calculated, and how to read the levels it produces

GEX — short for gamma exposure — is the number that turns a wall of options open interest into a handful of actionable price levels. It's the engine behind every Call Wall, Put Wall, and Zero Gamma reading on the dashboard. If you understand one concept in dealer flow, make it this one.

What GEX Actually Measures

Gamma exposure estimates how much of the underlying dealers must trade to stay hedged for each 1-point move in the index. It answers a single question: if SPX moves one point, how many dollars of hedging does that force?

The intuition: Gamma measures how fast an option's delta changes. Multiply that by how many contracts are open, and you get the size of the hedging trade dealers are forced into when price moves. GEX is that number, aggregated across the whole options chain.

How GEX Is Calculated

Per strike, the contribution is approximately:

Strike GEX ≈ gamma × open interest × contract multiplier × spot ...with a sign convention for dealer positioning: short calls → negative gamma contribution short puts → positive gamma contribution (dealers are typically assumed short calls / long puts, or the reverse) Net GEX = Σ (signed strike GEX) across every strike

Two outputs matter. Net GEX (the sum) tells you the overall regime. The per-strike profile (the distribution) tells you where the hedging concentrates — the levels you actually trade around.

Positive vs. Negative GEX

The sign of net GEX defines the day's character — this is the same regime split covered in depth on Positive vs. Negative Gamma:

Positive net GEX — dealers hedge against the move (sell rallies, buy dips). Volatility is suppressed, ranges are tight, pinning is strong.
Negative net GEX — dealers hedge with the move (buy rallies, sell dips). Volatility is amplified, moves trend and accelerate.
Zero GEX — the gamma flip level, where net exposure crosses zero and the regime changes.

How to Read the GEX Levels

The per-strike GEX profile produces the lines on the dashboard:

Call Wall — the strike with the largest positive GEX above spot; tends to act as resistance.
Put Wall — the largest negative-GEX strike below spot; tends to act as support (until the regime flips).
Zero Gamma — the gamma flip; above it volatility compresses, below it expands.
Max Gamma — the single highest-gamma strike, the strongest pinning magnet.

Why GEX Is Worth Watching

GEX is a positioning signal, not a prediction. It doesn't say price will go up or down — it says where dealer hedging will resist a move and where it will reinforce one. That's a structural edge: the levels are computed from open interest that's already on the books, not from a forecast. With 0DTE options now driving most SPX volume, the GEX profile rebuilds intraday, which is why these levels are recalculated continuously rather than once a day.

See live GEX levels

Net GEX, Call Wall, Put Wall, Zero Gamma, and Max Gamma updated in real time

View Live Dashboard

Dealer Flow Explained — the hub: how dealer hedging moves markets

Positive vs. Negative Gamma — the two regimes GEX reveals

Why Does SPX Pin at Certain Strikes? — how Max Gamma creates magnets

GEX Methodology — the full calculation behind our levels