Gamma exposure sounds like something out of a research note. It isn’t. It’s just a way of adding up hedging pressure on an options chain.
Dealers (market makers) sell a lot of the calls and puts you see on SPY, QQQ, NVDA, whatever. To not blow up, they hedge. Gamma is the piece of that hedge that changes as the stock moves. Stack it by strike, and you get a picture people call GEX.
You never see the actual dealer book. Nobody outside the desk does. What you get is a model: listed open interest, a guess that dealers sit on the other side of the crowd, gamma math, a chart. That’s the whole trick.
What the hedge actually does
Skip the formula for a second.
If dealers are long gamma, they buy dips and sell rips to stay delta-neutral. That can slow a move down. Price spends more time chopping. People call this a positive-gamma regime.
If they’re short gamma, the hedge goes the other way. They sell into weakness and buy into strength. Moves can run farther than they “should.” That’s negative gamma.
Is it always true? No. The model is wrong on thin names, around events, and whenever the “dealers are short what retail is long” assumption is garbage. Treat it as a weather map, not a GPS.
The three numbers everyone quotes
On a GEX chart you’ll keep seeing the same three labels.
We unpacked those properly in Call wall, put wall, and gamma flip. Short version here:
Call wall — the strike with the fattest pile of call-side gamma, usually above spot. In a positive-gamma tape it often behaves like a ceiling. Not because the universe said so. Because hedging flow there tends to sell into a rally.
Put wall — the put-side version, usually below. Same story, flipped. It can look like support until it doesn’t.
Gamma flip — the level where net gamma changes sign. Above it, the model says hedging leans toward damping. Below it, toward amplifying. It’s a regime line, not a buy stop.
On our Gamma tab those sit next to ABS GEX (how dense the gamma is at a strike, ignoring plus or minus), max +Gamma, max −Gamma, and the big open-interest strikes. Open interest is “how many contracts.” GEX is “how hard those contracts shove the hedge.” Different questions.
How to look at the chart without kidding yourself
I look at four things, in this order:
- Where is spot versus the flip.
- Where is the nearest wall.
- Is the gamma pile concentrated or smeared across strikes.
- Which expiries I’m actually summing. A 0DTE pile is not a monthly pile.
Then I stop. I don’t need a story about what “the market wants.” If price is sitting on a huge positive cluster, I expect it to be sticky. If it blows through that cluster, I don’t fade it on principle. The hedge that was holding the level is gone.
That’s it. No entry recipe.
Longer versions of those four reads: how to read a GEX chart, GEX vs open interest, positive vs negative gamma, 0DTE and the expiry filter. Related searches: what gamma is, what 0DTE is, implied volatility, what the VIX is, SPX vs SPY, put/call ratio.
What GEX is not
It is not a signal. It is not max pain. It is not “smart money.” It does not care about your iron condor.
A lot of write-ups turn this into a playbook: fade the call wall, buy the put wall, size it. That’s a fun tweet. It’s also how people donate money to the tape. The chart tells you where positioning is heavy. It does not tell you to click buy.
If you want the live picture, open Gamma on this site. Guests get a delayed snapshot. A free account keeps a journal and one full report. None of that is a recommendation to trade the levels you see.