Before the session
How to read SPY GEX levels
Learn what the green and coral bars mean, how to compare put and call walls, and how to turn a SPY gamma chart into a short list of price levels to watch.
Use GEX to choose prices worth watching. Then use price behavior to decide whether a level matters for your plan.
What does a GEX chart show?
Gamma describes how an option’s delta changes as the underlying price moves. Gamma exposure, or GEX, combines that sensitivity with open interest to show where options exposure is concentrated.
In Net GEX by strike, each bar represents an option strike. Green bars show positive net exposure and coral bars show negative net exposure under the platform’s call-minus-put convention. Taller bars show a larger absolute concentration.
Start with the largest concentrations near the market price. They give you a manageable list of areas to monitor instead of treating every strike as equally important.
Read the chart in four steps
- Check the symbol, data date and selected expirations. SPY with a 1W scope can have different leading levels from SPY with a 2W scope.
- Find the largest positive and negative bars. Note their strikes and how far they are from price.
- Compare each bar with nearby strikes. An isolated large concentration tells a different story from a broad cluster spread across several prices.
- Read the units before comparing amounts across views. Wall analysis reports USD per 1% underlying move; the legacy Net GEX chart uses its displayed exposure scale. Match the date, scope and units for a fair comparison.
What are put and call walls?
GEX Options ranks put walls by the largest negative net GEX and call walls by the largest positive net GEX in the selected scope. These are leading exposure concentrations, not a list of guaranteed support and resistance prices.
In EOD wall analysis, look beyond the primary strike. Compare its exposure with nearby strikes, its distance from the close, its same-expiry history and the expirations driving it. Those details help explain why a level stands out.
| Question | Where to look |
|---|---|
| Does this level stand out locally? | Compare its GEX with nearby strikes. |
| Is the exposure persistent? | Read the same-expiry history and top-three streak. |
| Could the picture change as options expire? | Check the expiry contribution breakdown. |
| Has price reacted to it? | Open intraday wall tracking and inspect completed price bars. |
Does positive GEX mean price will rise?
No. The sign describes exposure in the model; it is not a bullish or bearish price forecast. A large green bar is not a buy instruction, and a large coral bar is not a sell instruction.
The platform estimates exposure from options inputs and an inventory convention. It does not observe every dealer’s actual position or hedging trade. Use the gamma context alongside price, rather than assuming a bar tells you what market participants must do next.
A simple example: turn two levels into a watch plan
Hypothetical example: SPY is at 600, with a put wall at 595 and a call wall at 605. These are teaching numbers, not current SPY levels.
Your first job is to monitor whether price returns to either area. If price approaches 605, watch whether completed bars reject the area, stay near it, or move above and retest it. The wall alone does not choose the outcome.
If price stays around 600 and never approaches either wall, there may be no wall-based decision to make. Waiting is a valid result.
Use EOD levels for preparation, then follow the session
- Before the session, open SPY’s EOD wall analysis and select the expiry scope that matches your research horizon.
- For next-session preparation, check the displayed analysis date and included expirations. Expired contracts can change the exposure picture.
- Write down the nearby put and call walls and the main expiration behind each. Review the exposure map if one expiry dominates.
- During the session, open intraday wall tracking. It uses a fixed near-term 1W scope, so its levels can differ from an EOD view with another scope.
- If a setup is recorded, read its entry area, target and invalidation boundary at the displayed time. Compare with current price before making your own decision.
Common questions
Why does a wall change when I select another timeframe? You are changing the option expirations included in the calculation. More expirations can add or offset exposure at a strike.
Why is some wall history blank? Same-expiry history compares today’s selected expirations across prior dates. A dash means there is no comparable reading for that combination; it does not mean zero exposure.
Does a large expiry share mean the level will hold on that date? No. It means that expiry contributes much of the measured exposure. Its roll-off can change the level’s significance.
Your quick checklist
- Match the date, expiry scope and units.
- Pick a few nearby concentrations.
- Check which expirations drive them.
- Wait for an observed price response.