Dealer gamma, explained
Dealer gamma is the engine behind most intraday SPX moves. Here's the short version of what it is and why it shows up on the tape.
Most of what moves SPX intraday isn’t macro or sentiment. It’s market makers re-hedging the options they sold to everyone else. Dealer gamma is the name for that hedging treadmill, and it’s the single biggest source of mechanical order flow in the index. Get this concept and the rest of the dashboard makes sense.
What it is
Gamma is how fast an option’s delta moves. When dealers sell options to customers, they inherit a position with non-zero gamma — meaning their hedge isn’t stable. Every tick of SPX changes their effective exposure, and they have to buy or sell the underlying to stay neutral. That forced buying and selling is what we mean by “dealer flow.” Two flavors matter: long gamma (dealers damp moves) and short gamma (dealers amplify them).
How you use it
On SPX-Flow you read dealer gamma off the heatmaps. Long-gamma days look like quiet, range-bound action — yellow NET POSITION clusters tightly, blue GEX is positive and concentrated. Price gets pulled toward the dominant strike. Short-gamma days are the opposite: GEX flips negative near spot, ranges expand, breakouts run further than they should. The first thing to read every morning is which side dealers are on. That single read tells you whether to fade or follow.
Differentiated advantage
Most options-flow tools show you yesterday’s gamma, computed once at the close, and call it a day. SPX-Flow rebuilds the dealer book every 10 minutes through the session, so gamma you’re reading is gamma as it stands right now — not eight hours ago. That intraday refresh is what lets you spot a regime flip while it’s happening rather than after.
Why you should care
Trading without a gamma read is trading the residue. You’re reacting to the side effects of dealer hedging instead of front-running them. Once you know dealers are short gamma at 6188, you stop fighting the breakout. Once you know they’re long gamma at 6200, you stop chasing the breakout. The same chart pattern means opposite things depending on which side dealers are on.
GEX and what it misses
GEX was a real upgrade when retail tools added it. Here's what it gets right and the four things it leaves out.
GEX gave traders the first real map of dealer gamma. It’s still useful — but the way most tools render it leaves out the parts that matter intraday. Four gaps in particular are worth knowing about before you trust a GEX chart.
What it is
GEX (Gamma Exposure) is a per-strike measure of how much dealer gamma sits on the chain. Positive at a strike means dealers are net long gamma there (they damp moves); negative means net short (they amplify). Sum across the chain and you get the headline number that often gets called “the GEX read for the day.” It’s a real signal — and an incomplete one.
How you use it
Watch the per-strike map, not the headline. On SPX-Flow the blue GEX heatmap (#248aff) shows positive intensity at walls (where price gets defended) and negative intensity at accelerants (where price gets propelled). What naive GEX charts miss: the snapshot is yesterday’s, the second-order Greeks (vanna, charm) aren’t included, the directional consequence isn’t separated from the inventory, and there’s no spatial intensity between strikes — just bars. All four matter.
Differentiated advantage
SPX-Flow was built specifically against those four gaps. Snapshots refresh every 10 minutes across 14+ days of replay. Vanna and charm get their own first-class metrics (VEX, CEX) instead of being folded into a single number. Directional positioning is split out from raw inventory. And the heatmap renders real spatial intensity, so you can see where the surface is shifting between strikes, not just at them.
Why you should care
A 6200 wall on a naive GEX chart and a 6200 wall on SPX-Flow can mean different things. One is a snapshot from yesterday’s close; the other is the live book as of the last 10-minute refresh, with vanna and charm folded in. When the wall fails, the trader reading naive GEX gets run over. The trader watching the SPX-Flow surface saw it weakening 30 minutes earlier.
Naive GEX vs. real MM positioning
Position is the inventory list. Positioning is the forced behavior. Most tools show the first; the trade is in the second.
A position is a line on a dealer’s book. Positioning is what they have to do about it — the buying and selling forced on them by hedging requirements. These are different things, and the distinction is the whole game.
What it is
Position data is the inventory: how many calls and puts dealers own at each strike, frozen in time. Positioning is the script of mechanical actions that inventory forces — sell N futures at this price, buy M deltas if VIX drops half a point, re-balance against time decay every 30 minutes. Inventory is necessary input. Positioning is the consequence. Naive GEX tools publish inventory and let you guess at positioning. SPX-Flow computes the positioning and renders it directly.
How you use it
The pattern shows up on the tape constantly. A popular GEX tool flags a “huge call wall” at 6200, retail piles in to fade it, price slices through. What happened: the wall existed as inventory, but the positioning around it had already shifted — vanna had bled the defense, charm had moved the magnet, the dealer wasn’t required to defend that strike anymore. On SPX-Flow you read all five metrics together. GEX shows the inventory. NET POSITION, DEX, VEX, CEX show the forced behavior around it.
Differentiated advantage
The split into five metrics is what makes the positioning read possible. NET POSITION (yellow) is the directional book. GEX (blue) is static gamma. DEX (purple) fuses the second-order pressure. VEX (orange) isolates vol sensitivity. CEX (cyan) isolates time decay. Each one isolates a real hedging force that naive GEX folds into a single number and loses.
Why you should care
If your read is “GEX is positive, so price will pin,” you’re trading inventory. The trader on the other side is trading positioning — they know inventory is positive but the forced behavior is already breaking down. They’ll eat your fade. The fix isn’t to drop gamma data; it’s to stop using gamma data alone.
The five regimes
Every SPX session falls into one of five dealer-flow regimes. Reading the regime first is how you stop fighting the tape.
If you only learn one thing from this Learning Center, learn the regimes. Every SPX session resolves into one of five archetypes, defined by where dealers sit on the gamma surface. The regime dictates what plays work and what plays get cooked.
What it is
Five regimes cover almost every session: Pin (price magnetized to a dominant strike), Squeeze (short-gamma setup ready to break), Trend (dealers capitulated, hedging in one direction), Grind (gamma diffuse, low conviction), Transitional (the system is in flux, no clean read). The agent on SPX-Flow classifies the regime every 10 minutes and publishes it with a confidence score. Learning to read the regime by eye, before the agent prints, is how you build edge.
How you use it
Each regime has a metric signature on the dashboard. Pin: NET POSITION clustered tightly, GEX strongly positive at the magnet, DEX muted. Trade the fades. Squeeze: GEX negative near spot, DEX building, NET diverging from price. Wait for the breach, then ride. Trend: no walls in the move’s direction, NET walking with price. Stay with it. Grind: GEX positive but diffuse, no concentration. Stand aside. Transitional: metrics disagree, agent confidence drops below 50%. Don’t trade.
Differentiated advantage
Most flow products give you metrics and leave the regime call to you. SPX-Flow does both — the heatmaps for your own read, and an explicit regime classification with confidence and flip line so you have a second opinion every 10 minutes. Two reads on the same data catch more transitions than one.
Why you should care
Most retail losses on options-flow trades come from running a Pin playbook in a Squeeze regime, or vice versa. The chart pattern looks the same; the right trade is opposite. Regime reading is the filter that tells you which playbook to open. Get the regime right and the entry, target, and stop fall into place.
Time-series flow vs. snapshots
A snapshot shows a frozen moment. A time series shows the build. The signal is almost always in the build.
Most options-flow tools show you a snapshot. The good ones refresh it intraday; the lazy ones refresh it once at the close. Either way, you’re looking at one frame. Trading is a movie — and the part you most need is the direction and rate of change, not any single picture.
What it is
A snapshot is the dealer book as of one moment. A time series is a sequence of snapshots played back at 10-minute intervals over a session (or 14+ days). The dealer surface moves continuously: customers trade, dealers re-hedge, vol shifts, time burns. A snapshot collapses all that motion into one frame. A time series preserves the motion — which is where the signal lives.
How you use it
Two workflows on SPX-Flow. Live: scrub backward in 30–60 minute increments before placing a trade. The snapshot you’re looking at is consequence, not cause — the time series shows you how today got here. Off-hours: pick a session from the last 14 days, set the timeline to 9:30 ET, and step forward 10 minutes at a time, predicting what the next frame will show before you advance. When predictions get accurate, you’re reading flow. The replay is a practice rig.
Differentiated advantage
14+ days of 10-minute snapshots, fully replayable, isn’t standard in this category. Most tools keep the current state and discard the rest. Replay is what lets you watch a wall strengthen between 10:00 and 11:00 versus weaken — same wall on the snapshot, opposite trade.
Why you should care
Regime transitions happen in specific 10-minute windows. The minute Pin breaks into Squeeze, or Trend collapses into Grind, is visible on a time series and invisible on a snapshot. Catching the transition early is the difference between leading the move and reacting to it.