People mash GEX and open interest into one screenshot and call it positioning. They’re related. They are not the same question.
Open interest counts contracts still open at a strike. Calls, puts, or both. That’s Max OI Call, Max OI Put, Max OI C+P on our Gamma tab. How many tickets are parked here.
GEX — gamma exposure — estimates how hard those contracts shove a dealer’s hedge when price ticks. A strike can be crowded and quiet. A strike can be quiet and violent. That’s the whole split.
If you only watch OI, you miss the 0DTE magnet with fewer contracts and more gamma. If you only watch GEX, you miss the parking lot that still matters because a roll, a pin, or a lot of people live there. We draw both. On purpose.
If you want the live picture, open Gamma. This page is why the two columns refuse to match.
What open interest actually is
Open interest is a census. One contract open is one contract open. It does not know if that contract is a 0DTE lottery ticket or a monthly hedge. It does not know if dealers are short it. It does not know gamma.
A strike with huge put OI got there because people bought or sold a lot of puts and didn’t close them. Could be protection. Could be a spread. Could be yesterday’s panic that nobody rolled. The number is real. The story you glue on it is optional.
Max OI Put is the strike with the most put contracts. People nickname it the put wall. In a positive-gamma tape it can look like support, because in the usual model dealers are short those puts and buy dips into them. That’s a tendency in a model. It is not a bid on the book.
Max OI Call is the call version. The usual call wall nickname. Ceiling stories live here. Same caveat: OI is the crowd, not the shove.
Max OI C+P is the strike with the most combined call and put open interest. Sometimes that’s the call wall. Sometimes it’s a mixed round number where both sides parked. Traders love round numbers. The chart doesn’t care why.
OI updates when trades open or close. It does not update because implied vol moved. Gamma does. That’s already a reason they diverge during a vol spike: same contracts, different shove.
What GEX actually is
GEX takes those contracts, guesses that dealers sit on the other side of the crowd, multiplies by gamma, stacks by strike. You never see the desk. The guess can be wrong. Thin names, events, overwriting ETFs — garbage in, garbage chart.
What you get anyway is a profile of hedge pressure. +Gamma and −Gamma by strike. ABS GEX for density. A gamma flip where the net sign changes. That’s the map people screenshot.
Gamma is large when the option is near the money and near expiry. That’s why 0DTE can dominate a GEX chart with a fraction of the OI of a monthly. The monthly has the crowd. The 0DTE has the magnet. We wrote the expiry version in 0DTE gamma and the expiry filter. Here the point is simpler: OI does not know that magnet exists until you look at GEX.
GEX also cares about sign. A pile of long calls on customers is a different hedge than a pile of short calls. OI just adds the tickets. If you want regime — positive versus negative gamma — you need GEX, not a contract count. That’s positive vs negative gamma.
When they agree
Often they sit in the same neighborhood. Fat call OI and fat +Gamma around 650. Fat put OI and fat −Gamma around 620. The tweet writes itself. Call wall, put wall, done.
Agreement is not proof. It just means the crowd and the shove live on the same street. You still need spot versus the flip, still need to know if the pile is 0DTE, still need to not fade it on principle.
When they agree, I still look at shape. One OI bar and one GEX bar at the same strike is a speed bump. A smear of both across five strikes is a neighborhood. How to read a GEX chart is the order. This page is why the two meters can both be loud.
When they disagree — that’s the interesting day
Two disagreements show up constantly. They’re the reason this article exists.
Parking lot. Huge Max OI Put or Max OI Call. Sleepy gamma. Quiet ABS GEX. Often far from spot, or deep in-the-money junk that still has tickets because nobody closed them. Lots of contracts. Little shove left. A crowd, not a wall that still pushes price. If you draw “support” on that put OI, you’re drawing a museum.
Loud hedge. Quiet open interest. Fat +Gamma or −Gamma bar. Near spot, short-dated, high gamma. Fewer contracts. More shove per tick. 0DTE loves this shape. OI alone would miss it. GEX looks like a skyscraper next to a bungalow of tickets. That’s not a bug.
There’s a third, quieter split: Max OI Call at 660 and Max +Gamma at 650. The crowd parked one strike up. The shove is closer to spot. If you only quote the call wall from OI, you’re a strike late. If you only quote GEX, you miss where the roll might be sitting. Look at both rows. That’s why the Gamma tab lists seven levels instead of one hero number.
Vol days split them too. Gamma changes with implied vol and with moneyness as spot runs. OI lags until people trade. Morning GEX can look violent on yesterday’s OI. That’s a map of the leftover book plus new vol, not a census of new conviction.
Around events the split gets rude. A FOMC afternoon, an earnings print, a sudden vol crush — gamma reprices immediately. Open interest is still yesterday’s tickets until someone closes or opens. If you screenshot OI levels at 10 a.m. and GEX at 10:20 and they argue, that’s not the data feed breaking. That’s two clocks. GEX is the faster clock. OI is the slower one. I don’t throw the slow clock away. I just don’t let it narrate a 20-minute move it hasn’t seen.
One more ugly case: Max OI C+P on a round number, GEX almost nothing there, real shove two strikes closer to spot. Round-number gravity is an OI story. Hedge shove is a GEX story. Draw both or you’ll tweet the round number and miss the bar that’s actually loud.
What neither number is
Neither is max pain. Max pain is an expiry toy about which strike would hurt option holders the most. OI feeds that toy. GEX is a different toy. They can sit near each other. Coincidence plus pinning chatter, not a proof.
Neither is “smart money.” Retail, overwriting, structured products, dealer inventory — the chart does not know. OI is a count. GEX is a model of a count.
Neither is an entry. Fade the high OI, fade the high GEX, size it — that’s how people donate money to the tape. The chart tells you where positioning is heavy. It does not tell you to click buy.
OI is not GEX with the sign stripped. ABS GEX is GEX with the sign stripped. People mix that up because both feel like “how much is here.” ABS GEX is how much *gamma* is here. OI is how many *contracts* are here. Density of shove versus density of tickets.
How we show both on the Gamma tab
The gamma profile is GEX: cyan +Gamma, red −Gamma, purple ABS GEX. The seven rows mix the two languages on purpose.
OI language: Max OI Put, Max OI Call, Max OI C+P.
GEX language: Max −Gamma, Max +Gamma, ABS GEX, Gamma flip.
Tap a row. Read the sentence. If OI and GEX point at different strikes, don’t pick a favorite because a thread told you GEX is “more advanced.” Advanced is looking at both and noticing they split.
The expiry filter sums both. Change the dates and OI levels move too, not just GEX. A 0DTE-only view can show a tiny Max OI Call and a huge Max +Gamma. An all-expiries view can show the opposite. That’s the smoothie problem, not a data error.
Guests get a delayed snapshot. A free account keeps a journal and one full report. Pro is unlimited tickers, not a secret OI feed. Single names are noisier than SPY or SPX. A “Max OI Put” of a few thousand contracts on a thin name is not an index put wall. We still show it. Don’t read it like SPY.
A short way to use both without a playbook
- Where is the crowd (Max OI Call / Put / C+P).
- Where is the shove (Max +Gamma / −Gamma / ABS GEX).
- Do those strikes match, or is one a parking lot and one a magnet.
- Which expiries am I summing, because 0DTE breaks the match on purpose.
If those four are boring, good. Boring is the point. You wanted a map. You got two meters on the same map.
Also in this series: what GEX is, how to read a GEX chart, call wall / put wall / gamma flip, 0DTE gamma.