SPY gamma exposure (GEX) levels
SPY tracks the S&P 500, and its options are among the most actively traded in the US. Prism by GEXfreak turns that book into modeled levels on the SPY chart: gamma by strike, the call wall, the put wall and the gamma flip.
What Prism shows for SPY
- Gamma exposure by strike
- Modeled exposure for every listed SPY strike and expiry out to 90 days, grouped into nearest, 14, 30 and 90-day windows.
- Call wall and put wall
- The strikes where modeled call-side and put-side gamma concentrate, drawn on the SPY chart.
- Gamma flip
- The modeled price where net exposure changes sign, when one exists.
- Volume profile and data clocks
- Where trading concentrated, plus the timestamp of every input, so an old book never looks current.
What to know about the SPY book
SPY is the SPDR S&P 500 ETF Trust, which tracks the S&P 500.
- SPY options are American-style and physically settled, and a standard contract covers 100 shares.
- SPY lists an expiration on every trading day, so the nearest window can be dominated by same-day contracts. Compare it with the 14, 30 and 90-day windows before treating one level as the only one.
- SPX index options are a separate book with a different settlement and scale. Prism reads the SPY book, not SPX.
- Futures traders can read SPY levels beside ES without mixing the two price scales.
SPY GEX questions
- How is SPY gamma exposure calculated?
- Prism models gamma for every listed SPY strike and expiry out to 90 days, multiplies it by open interest, the 100-share contract size and price, and applies a disclosed sign convention: calls positive, puts negative. The result is dollars of gamma exposure per 1% move. It is a model, not a record of dealer inventory.
- What are the SPY call wall and put wall?
- The call wall is the SPY strike with the most modeled call-side gamma; the put wall is the strike with the most put-side gamma. They mark where modeled exposure concentrates. Price can pass through either one.
- What is the SPY gamma flip?
- The gamma flip, or zero gamma level, is the modeled price where net SPY gamma exposure changes sign. It can be absent or cross more than once, and it moves as open interest and price change.
Learn to read the levels
- Gamma exposure (GEX) explained, with the formula
- Call wall and put wall: how to read them
- Gamma flip (zero gamma level) explained
- Positive gamma vs negative gamma
- 0DTE options and SPY gamma exposure
- SPX vs SPY gamma exposure
- SPY levels for ES futures traders
Other books: QQQ gamma exposure · IWM gamma exposure
Live books need membership
Live SPY levels are part of a paid Prism membership. Prism is a charting and research tool, not investment advice. See pricing.