Autumn turns the CBOE end-of-day OpenClose files into a measured dealer-gamma map for SPX — no guessing who is long or short. Each file's true market-maker net (mm_buy − mm_sell) is banked per strike and expiry and summed into the standing dealer position, then weighted by gamma to show where dealers must hedge. A live overlay from the worker adds today's intraday flow on top. SPX only.
The method — spot & gamma
SpotDerived from the options chain by put−call parity (the SPX index print is gated, so this is not a live quote). Real GEX uses the spot from the latest file you banked; True MM uses the latest file you computed in GEX Flow. They line up only when both point at the same day's file.
GEX $Standing net × one today-gamma per strike — gamma rebuilt from the latest file at the current spot, vol-weighted IV, and time-to-expiry measured from today. So the dollar figure is the dealer's hedging requirement as of now, not a stale per-session snapshot. Real GEX and True MM share this gamma, so they tie out.
Exact vs approximateThe net and its direction are exact facts straight from the file. The gamma weight (the $ scale) is reconstructed from the file's own prices, so the magnitude is approximate. Inner ±5% / nearest 8 expiries use the today-gamma curve; far wings fall back to the banked gamma.
Real GEX tab
The banked standing dealer position. Green = dealers net long gamma (they fade moves — pin / mean-reversion around the strike); red = net short (they chase — moves extend through the strike). The small % under a cell is dealer ownership: net contracts ÷ the cell's open interest. Tap any cell for the contract-level breakdown.
| Cell $ | Share % | What it means | How to treat the level |
|---|
| +$ | +% | Dealers net long contracts, long gamma confirmed by ownership. Hedging sells rallies and buys dips around the strike. | Real dealer wall. Pin and mean-reversion logic applies. Closer to +100% = more mechanical. |
| −$ | −% | Dealers net short contracts, short gamma confirmed. Hedging chases price: sells drops, buys rips. | Real accelerant. Moves through this strike tend to extend. Near −100% = customers own nearly all of it. |
| −$ | +% | Conflict. Dealers still own contracts as of the last OI settle but the dollars net short: they sold in the latest session (% lags one day) or the short side carries the gamma weight. | Transition strike, usually small $. Recheck next bank: % follows $ down = unwinding; $ returns to % = noise. |
| +$ | −% | Mirror: latest-session buying flipped the dollars positive before the OI settle catches up, or the long side carries the gamma weight. | Transition the other way, dealers likely accumulating. Confirm next session. |
| any | 0% | Dealers flat. The OI is customer-vs-customer or firm/BD paper. | Gamma there is NOT dealer-hedged. The level is weaker than its size suggests. |
| any | Δ±% (dim) | Flow ratio, shown when part of the cell's OI predates your files: dealer net traded across the window ÷ current OI. Recent flow, not ownership. Can exceed ±100%. | Read as direction and pressure, not who holds the OI. A strong Δ against the $ sign flags a position changing hands. |
| any | ±100% | Dealers are one full side of every open contract. | The textbook GEX assumption, measured true. Highest-confidence cells on the board. |
GEX Flow tab
Per-strike, per-expiry heatmaps built from one or more banked files. Pick a metric from the sub-tabs. Gold lines across every grid mark the structure: flip · call wall · put wall · gamma peak.
Dealer Gamma
True MM FlowThe truest measured dealer read: net flow (mm_buy − mm_sell) accumulated as standing net × today-gamma. Ties out with the Real GEX tab. Direction exact, $ approximate.
Autumn Live FlowTrue MM plus the live flow streamed from the worker (~30s). Live flow is dealer-gamma signed: dealers go long what customers sell, short what they buy. When streaming, the banked base is re-gamma'd at the live spot so the whole number sits on one live spot. Off-hours it shows the banked MM at the file's EOD spot. A sign-accuracy / peak score grades it against the dashboard's live GEX.
Standingγ × open interest (calls + puts), magnitude only — where gamma sits (the walls). The dealer sign needs the call+/put− assumption and is deliberately omitted to keep this view facts-only.
Positioning
Customer NetCustomer net opening (buy-to-open − sell-to-open, all sizes), γ-weighted — the real non-dealer demand. Green = customers opened long γ, red = short.
Retail vs InstInstitutional (>199 lots) net opening, γ-weighted. A violet outline flags strikes where retail (<100) opened the opposite way — exact from the file's size buckets.
ParticipantsOne account class at a time (Market Maker, Customer, Firm, Broker-Dealer, Pro-Customer) — the audit view. Green = that class net bought. Firms are often the bigger counterparty.
DirectionAll smart money net opening, weighted by delta (not gamma) — true directional intent. Green = bullish (bought calls / sold puts), red = bearish. The tiny C±/P± tag shows which side they used.
Flow Quality
Persist ΔOI(open interest − previous OI) × γ. ΔOI is exact: green = OI built, red = unwound. It does not assign a dealer side — only that positions grew or shrank.
Open vs UnwindOpening ÷ (opening + closing) volume per strike. Bright = fresh positioning, dim = unwind / position-management. A quality score to pair with True MM Flow.
Reading the colors
Green = net long gamma / OI built / bullish. Red = net short gamma / unwound / bearish. The brightest cell in each expiry column is the peak. Gold level lines across the grids mark flip, call wall, put wall, and gamma peak — the same structure the live dashboard draws.
Replay page
Members scrub a recorded session bar-by-bar — the exact Flow GEX grid the live dashboard shows, captured every ~30s and kept for replay. Reach it from the Replay link up top.
Tickers & dayPick 1–3 tickers (shown side by side) and a recorded day from the calendar. Only days the recorder has captured are selectable.
Views & expiriesSwitch between Flow (dealer flow γ), Standing (γ × OI), Vanna, or All 3 for one ticker. Toggle which expiries show as columns (up to 10).
NET & PURERight-side columns: NET = the strike summed across the shown expiries; PURE = single-leg purity, the share of clean directional flow (not spread legs).
Peak & spotThe strongest cell in each expiry column is filled yellow (the peak). A dashed line marks the current frame's spot.
Scrubber & levelsDrag or play the day at 1–20×; the grid, spot, and levels update each frame. The table below the grid lists peak, flip, call/put walls, node, pull, pure per expiry.
Levels chart
A per-day chart of the key gamma levels through the session, drawn on the spot candles.
The levelsPeak, call wall, put wall, flip, and node plotted as dots — raw recorded values, each level holding until it changes (no smoothing).
Spot, timeframe & zoomA dashed spot line sits at the last candle's close. Pick a timeframe (1m / 15m / 1h / 4h / daily) and drag the price or time axis to scale, like any chart.