How to read the chart
- Green bars are call gamma, red bars are put gamma at each strike near the current price.
- Call wall: the strike with the most call gamma. Price often stalls as it approaches it.
- Put wall: the strike with the most put gamma. Price often finds buyers near it.
- Gamma flip: where cumulative net gamma turns positive. Above it moves tend to be calmer; below it they tend to be faster.
Why it matters for SPY
SPY has daily expirations, so 0DTE (same-day) options make its gamma picture change intraday. Index-level gamma also influences broad market volatility.
Treat walls as zones to plan around, not lines that must hold. Combine them with the trend, earnings dates and unusual options flow before acting.
Ways traders use it (examples, not advice)
- Set covered-call strikes near or above the call wall, where upside has tended to slow.
- Place stops beyond the put wall rather than right on it, where price often wicks.
- Expect bigger daily ranges when price is below the gamma flip, and size smaller.