The front-expiry flip and walls are withdrawn. An audit on 2026-09-22 found the flip was located by rounding noise in the far tail of the ladder and both walls collapsed onto the strike beside spot, so neither described dealer positioning. The open interest, strike count and net gamma on this expiry are still measured and returned by the API, but not shown on the page while the levels are withdrawn.
Dealer positioning is an assumption, not an observable: open interest shows that a contract exists, never which side a dealer holds.
The list is for the call wall, put wall, zero-gamma flip and net GEX computed from the overnight Cboe settlement. Nothing is sending yet. We will only email you when this launches, and you can leave the list any time. Spike alerts are a separate list and are not sending either.
A waitlist, not a subscription: nothing is sending yet, and no email has ever gone out. When the daily levels launch we will email you, and every email will carry an unsubscribe link.
Dealer positioning for SPX options: call wall, put wall, vol trigger and the zero-gamma flip, computed each morning across the full options chain from CBOE open interest and Schwab implied volatility, then refreshed through the session. We publish the overnight change in open interest behind the walls. Free, no signup required.
The net GEX figure is dollar gamma: US dollars of dealer gamma per 1 percent move in spot, computed as gamma x open interest x 100 x spot squared x 0.01. It is derived from settlement open interest rather than from trades, so it describes positioning as of the last published chain, not order flow. What gamma exposure is walks through the calculation, and negative gamma explained covers what changes when the total flips below zero.
This page is the current SPX net gamma exposure total and the levels derived from it. For the same book broken out by strike and expiration, use the gamma exposure heatmap. The two totals are computed from different inputs and are not directly comparable. For the daily written read of the number, see SPX net GEX today.
Opens the free terminal: these levels plus delayed unusual-options activity, no signup. Want them by email when that launches? Join the waitlist.
As of 2026-09-28, SquawkFlow computes SPX dealer gamma exposure at $64.09B with spot at $7,700.41. The call wall sits at $7,800, the put wall at $7,500, and the zero-gamma flip at $7,663. The gamma regime is positive (dealers net long gamma). These levels are derived from Cboe open interest settled 2026-09-25, not from intraday trading, and dealer positioning is an assumption, not an observable.
Dealers are net long gamma, so hedging flow leans against price moves, the historical signature is mean reversion and suppressed intraday range.
This total is computed from the gex_v2 book, where every contract in the chain is re-priced with Black-Scholes at the evaluation spot from an archived implied volatility surface, once per session. The /gex-heatmap total is a different book, summed from the gamma published with each contract on the delayed Cboe chain, so the two totals are not directly comparable. Both derive from daily-settled Cboe open interest. When the gex_v2 book is unavailable this page computes the levels instead from the delayed Cboe chain over a window of strikes around spot, which covers less of the option book; the payload labels that third calculation chain_gamma_fallback_v1 and states its own coverage. Before 2026-09-10 that fallback published its totals on a per-point formula roughly spot/100 smaller than the per-1% unit its payload claimed, so a fallback figure dated before 2026-09-10 is not comparable to one dated after it.
Computed from the full SPX options chain using 2026-09-25 settlement open interest across 19,685 contracts. Dealer positioning is an assumption, not an observable: open interest shows that a contract exists, never which side a dealer holds. Machine-readable version.
SPX GEX
Spot refreshes; levels are settlement-datedLOW VOL
Last updated: 0s ago
Net GEX
$64.09B
Spot
$7700.41
Zero Gamma / Flip
$7663
Max Gamma
$8000
Call Wall
$7800
Put Wall
$7500
Vol Trigger
$7714
Pin Strikes
$8000 · $7700 · $7000
+630,544Net open interest change overnight2026-09-24 to 2026-09-25 settlement · largest at 8,000 (+44,799)Per-strike →
Dealers are net long gamma. Hedging a long-gamma book means selling into strength and buying into weakness, so those flows lean against price moves rather than with them. Spot $7700 is below the Vol Trigger $7714, the level below which the book's hedging flows lean with price rather than against it.
Expected range today$7679 – $7808
KEY GAMMA LEVELS (10)
7500SUPPORT-2.6%
7600SUPPORT-1.3%
7651SUPPORT-0.6%
7676SUPPORT-0.3%
7701RESISTANCE+0.0%
7776RESISTANCE+1.0%
7799RESISTANCE+1.3%
7825RESISTANCE+1.6%
7850RESISTANCE+1.9%
7899RESISTANCE+2.6%
Want per-strike open interest, nearly 200 tickers, and flow alerts?
Every structural change in the gamma picture, timestamped as it happened, Monday, September 28. Levels relocating, spot crossing the flip, and walls being pressed. A description of what the levels did, not a call on what comes next.
SPX gamma session log for Monday, September 28
Time (ET)
Event
Spot
What happened
10:00
REGIME
7,705.45
Session opened in positive gamma, with the flip at 7,662.6 (42.9 beneath spot). Dealer hedging dampens moves.
10:00
RELOCATION
7,705.45
Zero-gamma flip relocated 7.7 lower to 7,662.6 from 7,670.3, the line between dampened and amplified hedging moved with it.
11:00
QUIET
7,681.98
No structural change: spot -23.5 to 7,682.
15:00
CLOSE
7,700.41
The record ends at 15:00 ET with the reference price at 7,700.4, -5 from the first snapshot at 7,705.5. No later snapshot was captured for this session.
What is Gamma Exposure (GEX)?
Gamma exposure (GEX for short) measures how much dealers must buy or sell of the underlying index (here, SPX) as prices move, in order to stay hedged on the options positions they hold. Because market makers are the counter-party to most options trades, their aggregate hedging flow can be a large buyer or seller of the underlying.
Positive GEX means dealers are net long gamma. As price rises they must sell into the move, and as price falls they must buy, a stabilizing, volatility-suppressing regime. Negative GEX inverts that flow: dealers chase price higher on the way up and add to the sell pressure on the way down, so intraday moves get amplified and trends persist.
How dealers hedge, and why traders watch it
Every figure on this page rests on one convention about who holds which side. Against customer flow the dealer is long the calls and short the puts: covered calls and collars sell calls to the desk, and demand for downside protection sells puts to it. Long calls carry positive gamma. Short puts carry negative gamma. The sign on net GEX is simply which of those two sides is larger on the day.
When the long-call side dominates, the book is long gamma. Its delta rises as price rises, so the desk sells the index into strength, and its delta falls as price falls, so it buys the dip. That two-sided hedging is what pulls price toward the strikes carrying the heaviest gamma. When the short-put side dominates, the book is short gamma and the arithmetic runs the other way: a short put carries positive delta that grows as spot falls, so a delta-neutral desk sells into the decline, and sells more the further it goes. That is amplification rather than support, which is why heavy put gamma below spot is not the floor it is usually described as. The gamma squeeze story runs on the opposite positioning, a desk short the calls, which this convention does not grant. None of it is measured: open interest records that a contract exists and never which side a dealer holds.
The reason traders watch the GEX chart is the flip level between positive and negative gamma. Under the dealer convention above, hedging runs against the move above the flip and with it below. That is the flow the convention implies, not a measurement of how often price has behaved that way, and this page publishes no hit rate for it.
Gamma describes what a hedger has to do when price moves. Vanna exposure and charm exposure describe what the same book does when price does not move, and the live SPX figures for both sit in the vanna and charm exposure section further up this page. Why the market moves in the last hour separates that flow from the closing auction, which is a different thing that lands in the same window.
How to read this chart
The top metrics tell you the four levels most GEX-informed traders track:
Zero Gamma / Flip: the price where net dealer gamma crosses zero. Above = suppression. Below = amplification.
Call Wall: the strike above spot with the largest positive call gamma. Acts as a magnet-ceiling on rallies.
Put Wall: the strike below spot with the largest negative put gamma. Acts as a support-floor when it's been building. Call wall and put wall compared covers why the put wall does not simply mirror the call wall.
Vol Trigger: the lowest positive-gamma strike between the walls. Below it, hedging flow amplifies moves. Above it, hedging suppresses.
Underneath, the chart shows whichever the current data supports. When the daily snapshot is driving the page you get the key gamma levels, the support and resistance strikes it publishes, ranked by distance from spot. When the page is computing from a live chain instead, you get net GEX by strike: green bars are net positive gamma (dealers pin toward the strike), red is net negative (dealers reject it), and big clusters of one color near spot are where that hedging would concentrate if the convention holds.
How this chart is calculated
The walls come from a full-chain snapshot built once each morning before the open: CBOE settlement open interest for every listed SPX strike and expiry, roughly 21,000 contracts, crossed with Schwab implied volatility. For each contract we take gamma × open interest × 100 × spot, sign calls positive and puts negative (dealer perspective), and aggregate to a net figure per strike. That is the standard SpotGamma-style formulation, no proprietary smoothing, no vendor-locked feed.
Because the input is settled open interest, the walls are fixed for the session, they do not move tick by tick. What does update is everything around them: a refresh every 30 minutes through the cash session repoints spot and the expected range. Alongside the walls we publish the net change in contracts open across the chain from the previous settlement to this one, counted from our own archive. If that snapshot is missing or too old to describe today's tape, the page falls back to computing the same formula live from the CBOE chain, fewer expirations, no open-interest comparison, but the arithmetic is identical.
The front-expiry row above covers the contracts expiring on the nearest listed date and nothing else. Its flip and walls are withdrawn, and the row says why; what the extra night changes covers why a same-day round trip never reaches the settled open interest any of these levels are built from. For the probability the option chain prices on settling above a specific level, rather than the range, the market-implied odds page reads it off the same chain.
One derivative past gamma. Charm is the dealer delta that time alone removes from the book, and vanna is the dealer delta a move in implied volatility adds or removes. What vanna exposure and charm exposure measure defines both in plain language.
SPX CHARM INTO THE CLOSESeptember 28, 2026 session, captured 2026-09-28T19:15:50+00:00
Between 3:15 PM ET and the 4:00 PM ET close on September 28, 2026, time alone moves this book's dealer index delta by -$1.13B. Re-neutralising that drift means buying the index.
Of that, -$353M comes from contracts expiring on September 28, 2026, which is the part of the book whose charm changes by the hour rather than by the week.
-$61.75B
Net charm, dollars of dealer delta per day, at the capture
+$61.10B
Net vanna, dollars of dealer delta per +1 implied vol point
$7,699.72
SPX spot at the capture
Running total of dealer index delta the clock removes from the book, sampled from the half-hourly ramp. The chart above draws the expiring-that-day column. The full half-hour series is on the endpoint.
Exchange clock
Minutes to close
Charm per day
Delta shed since capture
Of which expiring that day
Implied hedge
3:15 PM ET
44
-$61.75B
$0
$0
none
3:30 PM ET
30
-$36.62B
-$484M
-$235M
buy
4:00 PM ET
0
-$25.24B
-$1.13B
-$353M
buy
Spot and every contract's implied volatility are held at the values they carried at the capture. Time to expiry is the only variable that moves across the ramp, so this is where this book would sit at each mark if nothing else changed, not a claim about where it will sit. Time to expiry is floored at 30 minutes, because charm diverges as expiry nears and below that it stops being a hedging estimate. So the last half hour before the close is not modelled: contracts expiring into that close are held at the floor and drop out at the close, and the final step is a straight line between the two. The drain to the close includes that step.
SPX VANNA PROFILE BY STRIKE795 strikes analysed, 15 shown
Dollars of dealer index delta that a one point move in implied volatility adds or removes at each strike. Green bars are strikes where a vol rise pushes dealer delta up, red where it pushes dealer delta down. The sign carries the same dealer-side assumption as every gamma figure on this page.
Bars are scaled against the largest absolute vanna in this window, so widths compare within the profile and not across sessions.
Strike
Vanna per vol point
Magnitude
Charm per day
$7,665
+$26M
-$745M
$7,670
+$10M
-$713M
$7,675
+$24M
-$4.15B
$7,680
+$30M
-$1.67B
$7,685
+$23M
-$3.92B
$7,690
+$15M
-$2.55B
$7,695
+$6M
-$1.23B
$7,700
-$6M
+$208M
$7,705
-$10M
+$1.97B
$7,710
-$15M
+$3.89B
$7,715
-$1M
+$938M
$7,720
+$13M
+$2.63B
$7,725
+$3M
+$1.08B
$7,730
+$48M
-$38M
$7,735
+$4M
-$630M
What a volatility move is worth, in delta
Vanna is a first derivative, so this ladder is linear in the shift by construction. It is the multiplication done in dollars, not a separate measurement, and it holds spot and the rest of the book fixed.
Both figures are computed with Black-Scholes at zero rates from each contract's own implied volatility on the delayed Cboe chain, weighted by settled open interest across 21,607 priced contracts and 56 expirations. They are model outputs rather than values the feed publishes, and they are quoted in dollars of index delta rather than dollars of gamma, so they are not comparable to the net GEX total above or to the gamma heatmap total. Dealer positioning is an assumption, not an observable. Vanna and charm explained covers why the direction of these flows depends entirely on who holds which side.
Dated change points in SPX net gamma exposure
A change-point search splits this daily series into stretches with different mean levels and dates the split. Each entry below is one of those dates, found under the penalty printed with it. Nothing here is a reading of where the series goes next.
DATED CHANGE POINTS UNDER PENALTY 7.612026-07-28 to 2026-09-28, 45 daily observations
The 3 most recent dated breaks in SPX net gamma exposure, most recent first, each found under penalty 7.61. Means are in USD billions and cover the segment on each side of the date. The full list, with the minimum and maximum of every segment, is on the endpoint.
Date
Direction
Mean before
Mean after
2026-09-22
up
0.16
68.75
2026-08-18
down
76.19
0.16
2026-08-04
up
-7.20
76.19
The current segment has persisted since 2026-09-22: 5 daily observations averaging 68.75 USD billions, with a low of 15.06 and a high of 91.63.
Method: PELT change-point search at penalty 7.61, set by 2 * ln(n) on the standardised series, with cost model l2, least squares about a per-segment mean. Minimum segment length 5 observations. Window 2026-07-28 to 2026-09-28, 45 daily observations. Source: D2DT gex_v2 daily archive (read-only). The penalty is the only judgement in the procedure, which is why it is printed beside every break rather than left in a footnote. How change point detection works walks through the search, the penalty and what a dated break does and does not establish.
A dated break describes the past series only. It is not a forecast and carries no claim about what the series does next.
Trade the chart, not the noise.
SquawkFlow bundles SPX GEX with 30+ other Bloomberg-style panels, delayed unusual-options activity, the DIX dark pool index and market narration, free during beta with every feature unlocked.