Gamma exposure (GEX) explained
The short answerGamma exposure (GEX) estimates how much stock options dealers would have to buy or sell to stay hedged for each 1% move in the price. When dealers are long gamma (positive GEX), their hedging trades against the move and tends to calm it; when they are short gamma (negative GEX), it trades with the move and can stretch it.
Gamma in one line
An option’s delta is how much its price moves when the stock moves $1. Gamma is how fast that delta changes. A market maker who wants no direction (“delta neutral”) must keep re-hedging as delta changes — and gamma says how much.
From gamma to GEX
For each strike, the gamma of every open contract is multiplied by its open interest, by 100 shares and by the price, and scaled to a 1% move. Adding all strikes gives a dollar figure: “dealers must trade about $X of stock per 1% move”. Because nobody sees the dealers’ real book, GEX rests on an assumption about who is on which side — the common one is that investors mostly buy puts (for protection) and sell calls (covered calls), which leaves dealers long call gamma and short put gamma. That is why GEX is an estimate, and why different sites show different numbers.
Positive and negative gamma
- Positive GEX (dealers long gamma): as the price rises, they sell; as it falls, they buy. Their hedging leans against moves, so ranges tend to be tighter and dips tend to be bought.
- Negative GEX (dealers short gamma): as the price rises, they buy; as it falls, they sell. Their hedging adds to moves, so swings tend to be larger and faster.
The price where the total changes sign is the gamma flip.
What GEX does not tell you
- It is not a direction signal: negative GEX means moves can be bigger, in either direction.
- It is end-of-day: options opened and closed the same day (0DTE) are not in the open interest it is built from.
- News, earnings and the wider market can overwhelm hedging flows at any time.
Live example: SPY and QQQ today
From the close of Fri, Nov 13, 2026 — this box is rebuilt after every trading day.
SPY (754.21 on Nov 13, 2026): net GEX −$8.64B per 1% move — dealers short gamma for 23 sessions in a row; about 72% of it sits in expirations within 14 days. Page: SPY.
QQQ (679.89 on Nov 13, 2026): net GEX −$4.42B per 1% move — dealers short gamma for 25 sessions in a row; about 47% of it sits in expirations within 14 days. Page: QQQ.
Questions and answers
Is positive gamma bullish?
Not by itself. Positive gamma means dealers’ hedging tends to dampen moves in both directions; it says more about volatility than about direction.
What does “GEX per 1% move” mean?
It is the dollar amount of stock that dealers would need to buy or sell to stay hedged if the price moved 1%, under the usual assumption about who holds which options.
Where can I see gamma exposure for a stock?
Every ETF and stock on this site has its own page with net GEX, whether dealers are long or short gamma and for how many sessions — and the daily GEX history as a free CSV.
All 10 lessons: Learn · every term in one long page: the full guide · the numbers for any ticker: ETFs, stocks. For education only — not investment advice.