What is GEX (gamma exposure)?
Gamma exposure (GEX) is a measure of how much the options market makers who sold the open interest must trade in the underlying to keep their books delta-neutral as price moves. Because those dealers hedge mechanically, their aggregate gamma position tells you whether their hedging will DAMPEN a move or ACCELERATE it — which is why GEX has become a widely-watched map of intraday support, resistance and volatility.
Where the hedging pressure comes from
When a dealer is short an option, they are short gamma: as the underlying rises their delta falls, so they must BUY to re-hedge, and as it falls their delta rises, so they must SELL. That is destabilising — they trade WITH the move. When a dealer is long an option they are long gamma and do the opposite, buying dips and selling rips, which is stabilising. GEX sums this hedging requirement across the whole chain.
The sign and size of that sum is the whole story. A large positive GEX means dealers, in aggregate, lean against moves; a large negative GEX means their hedging feeds the move. The exact strikes where the gamma piles up become the levels traders watch.
Positive versus negative gamma regimes
In a positive-gamma regime, dealer hedging is mean-reverting: rallies get sold and dips get bought, so realised volatility tends to compress and price gravitates between the heaviest strikes. In a negative-gamma regime the same hedging is trend-amplifying: moves beget more hedging in the same direction, so ranges expand and trends run further than they otherwise would.
The line separating the two regimes is the zero-gamma (gamma flip) level, and the heaviest positive-gamma strikes above and below price become the call wall and put wall.
How VolStrata computes it
VolStrata rebuilds the dealer-gamma profile from the live options chain, strike by strike and expiry by expiry, then nets it into the levels each data page cites: the call wall, the put wall, the zero-gamma flip, max pain, the expected move and the net GEX total. Every level a page shows is a computed value, never an estimate, and every historical call is graded on the public accuracy scoreboard.
FAQ
What does GEX stand for?
GEX stands for gamma exposure — the aggregate amount options dealers must trade in the underlying to stay hedged as price moves.
Does positive GEX mean the market will go up?
No. Positive GEX describes VOLATILITY, not direction: it means dealer hedging tends to dampen moves and pin price between the walls, whether the tape is green or red.
Where can I see today's gamma exposure?
VolStrata publishes the live per-ticker gamma map — call wall, put wall, zero-gamma, max pain and net GEX — free, and grades every level on a public accuracy scoreboard.
Educational, not financial advice.
Free live daily gamma map: VolStrata