Using the GRC band on a chart
See where gamma on the current book is concentrated, and how wide that zone is.
In this article 7 sections
What the GRC band is
GRC means gamma concentration. The line is the strike where the most gamma on the current book sits. The shaded band is the zone around that strike, sized as one hour of the session’s own volatility.
The chart on this page is QQQ on 11 Sep 2026. That day’s GRC is 715, and the band runs from 714.04 to 715.96. The open, 715.66, was already inside it. The call wall on this chart is 710 and the put wall is 700, so the combined concentration is not the same strike as either wall.
It is a structural mark. It shows where gamma is concentrated. The decision stays yours.
Sources: Options Industry Council (OCC): Gamma.
One session, two gamma horizons
Compare the two flips and untouched primary walls.
Choose a checkpoint for 1-minute detail. Later prices stay hidden.
A flip crossing alone is not an entry.
Historical review. Plans are hypothetical; fills, delivered signals and a trading edge are not proved.
- Context
- Preopen walls: call $710.00, put $700.00. Flips: ≤1 DTE $716.60; ≤7 DTE $718.05. ≤1 DTE is not 0DTE-only. The 15-minute-delayed model was stale; alerts were suppressed. Pause until model timing and a fresh broker quote are verified. No order was authorized.
- Wait for
- The 09:55–09:59 block closed $716.82 above the short-horizon flip, known at 10:00 ET. This is an observation, not an automatic entry.
- Execution
- No order is specified or executed. Define entry, invalidation and risk separately using fresh quotes and acceptable spreads. Shorts require borrow; size must fit buying power. No option or futures trade is inferred.
- Invalidation
- A completed close back below the same flip challenges the hold-above idea. Keep the horizon fixed.
- Management
- Follow completed closes. Wait for any separately required wall touch. If no condition qualifies, staying out is valid.
Above at 10:00 ET; back below at 10:01. The session had 18 strict adjacent-close crossings; neither primary wall was touched. The weekly $718.05 flip stayed above the session range. No entry, alert, fill, edge or P&L is established.
Source, timestamps & selection
- Candles
- Databento XNAS.ITCH · venue OHLCV, not consolidated SIP volume. These are venue bars, not a consolidated market tape.
- Model source
- Tradier sandbox · original archived native model. Source delay: 900 seconds.
- Model built
2026-09-11T07:03:58.932043+00:00- First recorded
2026-09-11T07:08:32.318429+00:00- Open interest timestamp
- Unknown. No point-in-time open-interest clock was supplied.
- Evidence limit
- A local producer cycle recorded this model before the cash open. The producer log is mutable and has no independently sealed receipt. The first and selected records report stale=true and alerts_suppressed=true; no enabled alert, trader broadcast or execution is proved. Exact OI availability is unknown. The chart uses a different price provider. Bar-end times are the earliest theoretical observation times after a minute closes, not proven client delivery times.
- Why this day
- Four editorial examples selected after reviewing all 12 SPY/QQQ/IWM sessions from September 8–11, 2026. Hindsight selection is explicit. Untouched levels, recrossings and the invalidation-first case remain visible; no hit rate or predictive performance is claimed.
The producer record is mutable. “First recorded” describes the recorded archive; it is not proof that a trader received the same levels at that instant.
Archive fingerprints
- resource-case-study-census.json
af9379d9eb6802044356957fd6cf9a96b203eb57bddafd844c2d56ebf679de85 - cycles.parquet
cb31c638974f19aea8cd9bc5b0bc0366f088e49ed69369d72f131823138b742f - contracts-QQQ.parquet
7d0c5c93cc5fd95b5e70865e74765fb3c33b8cbaee4d88be42da9f2ec7ba7c62 - QQQ-preview.json
c7650ac0a1d9b5d4fc8cb3e66df8d5c07b578067a54f9874b5b36d0a161a9471
Explore the concept with a simplified model
How it differs from the call and put walls
The call wall is the strike with the most call-side gamma. The put wall is the strike with the most put-side gamma. Those two levels stay on their own layers.
The GRC uses the combined gamma at each strike, calls and puts together. On some sessions it lands on the same price as a wall. On others it sits somewhere else, because the combined book is not the same object as one side of the book.
How to turn it on
In the chart’s level row, press GRC. The same control is in workspace settings as GRC band. It starts off, so the call and put walls look the same until you ask for it.
The chip shows the wall price when the band is on. Press it again to hide the band.
- GRC in the level row shows or hides the band.
- The call wall and the put wall stay available on their own controls.
- The band uses the strike gamma already drawn for that symbol.
What the width means
The width is one hour of that session’s realized volatility, scaled the way a price move scales with time. A quiet session draws a narrower band. A louder session draws a wider one.
When a morning open-interest book is available, the level is also recomputed with time running to 16:00 ET on the expiry date, and the same-day expiry stays in the book. Open interest is a clearing print, not a live positioning feed through the day.
How this sits in a plan you already have
Use the band as a place to look: where gamma is piled up, how wide that pile is, and whether price is already inside it. It does not choose an entry, a stop, or a direction.
- Notice whether price is outside the band, touching it, or already inside it.
- Keep the call wall and the put wall in view when you want each side of the book separately.
- Read the model clock before treating the band as current.
- If the book is a demo or a dated archive, treat the band as that book, not as a live print.
What it does not do
The band does not reveal who holds the contracts or how they hedge. Price can travel through it. A later update can move the strike as spot and time change.
Check price structure, liquidity and event risk before you apply your own plan.
Sources: Cboe — Mandy Xu: Much Ado About 0DTEs: Evaluating the Market Impact of SPX 0DTE Options.
Sources and editorial notes
Read the primary references and editorial policy
Published by GEXfreak. Prism by GEXfreak is the product described in these guides. Definitions reference the primary sources below; examples and tool-selection checklists are GEXfreak’s own illustrations. This is product education, not independent investment research.
These sources explain options mechanics and data. They do not endorse Prism or validate the predictive value of its levels. Undated pages are marked below; the checked date is when the source was reviewed.
- Gamma — Options Industry Council (OCC). Publication date not stated. Checked .
- Frequently Asked Questions — Cboe DataShop. Publication date not stated. Checked .
- Much Ado About 0DTEs: Evaluating the Market Impact of SPX 0DTE Options — Cboe — Mandy Xu. Published 2023-09-08. Checked .
For the product’s calculation and data boundaries, read Prism’s methodology.
Open the paid workspace.
Membership is required for live SPY, QQQ and IWM books. Turn on the GRC band beside the call and put walls.
Demo values are fictional. Create an account to save your layout; review current access conditions on the pricing page.