Every GEX dashboard shows you now. Changes shows you now against yesterday.

A call wall at 690 means one thing if it was 690 all week and a different thing if it was 680 yesterday — and a screen that only shows today cannot tell you which. Changes is the new second tab in GammaGrid: pick any two trading days and read what moved — the walls, the gamma flip, max pain, IV, put/call and open interest — as a ladder of was → now → change, with both days' GEX profiles drawn over each other. Here is what each line measures, why the units are what they are, and how to actually use it.

Published 13 Sep 2026 · updated 16 Sep 2026: the same ladder can now be asked for inside ChatGPT or Claude — see the end.

Dealer gamma exposure, the walls, max pain, the flip — every one of those is a level. Levels are only interesting relative to where they were. "The put wall is at 680" is a coordinate; "the put wall moved up from 675 overnight" is an event, and events are what you act on, share, or at least notice. Every free GEX page on the internet shows you the coordinate, because that is what you can compute from a chain you fetched a minute ago. None of them can show you the event, because none of them kept yesterday.

GammaGrid does keep it — every chain it has ever collected is still there — but until now that history was hidden behind a replay selector in the heatmap and a "load full history" switch in the sidebar. Two dropdowns is not a product. Changes is the attempt to make the one thing only a history-keeping tool can do into the first thing you see.

What is on the screen

Three parts, top to bottom.

Two days. The header is a pair of day pickers with an arrow between them, defaulting to the previous trading day → the latest one. Quick picks under it — 1 day, 1 week, 1 month — move the earlier day back by one, five or twenty-one trading days; Latest resets. The pair goes into the address (/t/SPY/changes?from=2026-09-10&to=2026-09-11), so a link you paste opens the exact same comparison for whoever follows it. Each day is read at its last snapshot — the close-of-day chain, not whichever fifteen-minute frame happened to be first.

The ladder. Fifteen lines, one per figure the product already computes, each with three cells: the earlier day's value, the later day's value, and a chip saying how it changed. A one-sentence headline above it says the most important thing first — the weather regime if it turned, otherwise which levels moved, otherwise "same weather as the day before; the levels held".

One chart. Net GEX by strike for both days on the same axis: the earlier day as an outline, the later day filled in the colour of its regime, both spots as dashed lines. The window is ±10 strikes around the money, the same as the heatmap, so the two agree. Under it, a button renders the comparison as a square card for a post.

The ladder, line by line

Two design rules run through all of it and are worth stating, because they are not what a spreadsheet would do.

Colour is the regime, not the direction. Everywhere in GammaGrid green means damping (positive dealer gamma, hedging that leans against moves) and purple means amplifying (negative, hedging that leans into them). The ladder keeps that language: a chip turns green when a line moved towards damping and purple towards amplifying, and stays in plain ink when it merely moved. "Price up" is not green. "Net GEX went from negative to positive" is.

"Unchanged" is the quietest chip, on purpose. It is the most common answer — walls hold for days, expiry counts hold for weeks — and a screen where fifteen lines all shout is a screen where nothing does. A dashed chip means unchanged; your eye goes to the ones that are not.

A real pair of days

From our own collection, on a delayed public chain rather than the paid source, so I can show it here whole: Altria (MO), Monday 15 September → Tuesday 16 September 2026, last snapshot of each day. The headline the product wrote was "Gamma weather turned from storm to fair." The top of the ladder:

Read it top down. The regime crossed: net dealer gamma went from short to long, so the hedging that was leaning into moves on Monday is leaning against them on Tuesday — that is the green chip, and it is the only green on the screen. The walls did not move at all; a screen showing only Tuesday would give you 72.5 and 62.5 with no way to know they had been there for days. A flip appeared where on Monday there was none to report — with net gamma negative across the whole window, there was no crossing. Max pain for Friday's expiry slid down two listed strikes, from 72 to 71, while price rose. And open interest grew on both sides, calls a little faster.

None of that is a signal. It is the same set of facts the Overview tab shows you every morning, except now you know which of them are new.

How to use it — three habits

Morning, 1 day. Open your ticker, Changes tab, default pair. Read the headline, then the coloured chips if any. Thirty seconds, and you know whether the regime turned overnight and whether the walls moved. This replaces the thing you were doing anyway — squinting at today's heatmap and trying to remember yesterday's.

Monday, 1 week. One click moves the earlier day back five sessions. A wall that has drifted up three strikes over a week is a different story from one that jumped this morning, and the weekly pair is where slow drift becomes visible. This is also where max pain earns its line: compared for the same expiry across a week, you can see whether the "pin" is even holding still.

Around expiry, and before you post. On the day the nearest expiry rolls off, the max-pain line will tell you it is now measuring a different Friday — the note says which expiry was nearest before — so you do not mistake a roll for a move. And when a pair of days says something, the card at the bottom is the same ladder in a square, with the two dates and the ticker on it. A picture of an event travels; a picture of a coordinate does not.

Where the numbers come from, and the edges

One row per ticker per trading day, written by the collector from the last snapshot of that day — the same resolved chain and the same gamma-weather card the other tabs read, not a second calculation. "Trading day" is the New York date, the same rule the OI Delta tab uses, so two tabs on one screen never disagree about what "yesterday" was. Missing days are filled in from stored snapshots when the collector starts, so a ticker you added last month has a month of pairs to choose from, not one.

The edges, plainly. The first day a ticker is on record has nothing to compare against, and the screen says so instead of drawing chips. GEX is our approximation — the dealer's side of each contract is a heuristic, as it is on every page here, and the ladder inherits whatever that heuristic gets wrong on both days equally. A wall moving by one strike on an illiquid name can be a single trade. And the screen describes positioning; it does not say what to do about it.