GEX Definition
GEX stands for gamma exposure. It is commonly used to estimate how option market maker hedging may change as the underlying price moves. For SPX, traders often monitor GEX by strike because large option open interest can cluster around round-number levels and near-dated expirations.
Positive vs Negative GEX
Positive GEX zones are often interpreted as areas where hedging flows may dampen price movement. Negative GEX zones are often interpreted as areas where hedging flows may amplify movement. This is only a framework, not a prediction engine.
Gamma Walls and Gamma Flip
A gamma wall is a strike with unusually large gamma exposure. A gamma flip level is an area where the aggregate gamma structure may shift from positive to negative, or the opposite. Traders use these levels as context for support, resistance, volatility, and intraday risk.
Important Limitations
- GEX is an estimate, not an exact view of dealer books.
- Open interest can be stale during the trading day.
- 0DTE options can change the structure quickly.
- Use risk controls; this site is educational only.