SPX gamma exposure

What is GEX?

Gamma exposure (GEX) estimates how much the options market makers who are on the other side of open options positions must buy or sell the underlying to stay delta-hedged as it moves. It is calculated per strike from open interest and the option's gamma, then aggregated, and it is conventionally quoted as dollars of underlying per 1% move. GEX is a model of hedging pressure inferred from the option chain — it is not observed dealer inventory and not a record of anyone's actual trades.

What does positive or negative GEX mean?

Positive net GEX means the modeled hedge flow leans against price: as the underlying rises hedgers sell it, and as it falls they buy it, which mechanically damps realized movement. Negative net GEX inverts that — hedging moves with price, selling into declines and buying into rallies, which mechanically amplifies movement. The sign describes the direction of the modeled hedge, not the direction of the market.

What is the gamma flip level?

The gamma flip — labelled model zero gamma here — is the hypothetical underlying price at which aggregate dealer gamma crosses zero, dividing the positive-gamma region from the negative-gamma region. Ivolution computes it by repricing the whole exposure ladder across a range of hypothetical spot prices and finding the crossing, rather than reading it off a single strike. When the modeled exposure never crosses zero inside that range, no flip level is published at all.

What are the call wall and put wall?

The call wall is the strike carrying the largest call-side gamma concentration, and the put wall is its put-side counterpart. They mark where hedging activity is modeled to be densest, which is why they show up as the tallest bars on the profile above. They are descriptions of where exposure sits — not support, resistance, targets, or price predictions.

How do you read a GEX profile?

The profile reads as a distribution: each bar is one strike's modeled gamma, the sign shows which way hedging leans there, and the height shows how much exposure sits at that price. The tallest bars are the walls, and the point where the aggregate crosses zero is the flip. The chart is a snapshot of the option chain at one moment — it is redrawn as open interest and prices change.

Why is this page delayed?

This is a free, unauthenticated page, so it publishes the last completed session's closing structure rather than a live feed: the levels and the chart above are the engine's end-of-session snapshot for the session named on this page, and they stay fixed until the next session completes. Every value shown here is computed by the Ivolution engine from licensed options data; the page displays derived analytics only and never redistributes quotes or the tape. The intraday, continuously updating version of this profile lives inside the terminal.