Gamma is an options Greek. Not a chart. Not a squeeze. Not a wall. It’s how fast delta changes when the underlying ticks.
Delta is the slope: roughly how many shares of exposure one contract acts like. A 0.30-delta call behaves a bit like 30 shares (per contract, times the 100 multiplier in US equity options). Price moves a dollar, delta doesn’t stay 0.30. The amount it *doesn’t stay* is gamma.
If gamma is 0.05, a dollar up might take that call toward 0.35 delta. The person who is delta-hedging has to adjust. That adjustment, stacked across a whole chain, is the thing people screenshot as GEX.
This page is the Greek. The GEX article is the stack. If you want the live stack, open Gamma. Don’t skip this and then argue about call walls.
Delta first, or gamma is gibberish
Delta of a vanilla call sits between 0 and 1 (or 0 and 100, depending who is talking). Puts between 0 and −1. ATM is often near 0.50 in absolute value, give or take skew and rates. Deep ITM hugs 1. Far OTM hugs 0.
Traders use delta as a hedge ratio. Short a 0.40-delta call? The textbook hedge is long about 40 shares per contract. Stay flat, sleep (you will not sleep).
Price moves. The option is a curve, not a line. The hedge that was right a dollar ago is wrong now. Gamma is that error per tick. High gamma means the hedge goes stale fast. Low gamma means you can ignore a tick.
You don’t need the formula on a napkin. You need the shape: gamma is largest near the money and near expiry. Far from the strike, the curve is almost flat (OTM) or almost a straight stock line (ITM). Little bend. Little gamma. That’s why a 0DTE ATM option is a maniac and a one-year 40-delta leap is a nap.
Long gamma vs short gamma, on one contract
If you buy a vanilla option, you are long gamma. Your delta *helps* you when you’re hedging: the option gains delta as it goes your way, loses delta as it goes against you. The hedge buys dips and sells rips. That’s the shock absorber. You pay for it with theta — time decay. Quiet tape, the rent eats you. Wild tape, the curve pays. That trade is “realized vol versus implied,” not a GEX screenshot.
If you sell a vanilla option, you are short gamma. Delta runs against the hedge. Spot drops, you have to sell more. Spot rips, you have to buy more. Flow leans *with* the tick. That’s the fuel. You collect theta if nothing happens. If something happens, the curve is a frown.
Dealers sell a lot of the listed chain. In the *usual* model they’re net short what the crowd is long, so they’re net short gamma a lot of the time — until they aren’t. Overwriting, vol selling, a quiet book: they can be long gamma. You never see the desk. GEX infers. When the inference is wrong, the Greek on one contract is still true and the *stack* is lying.
Why 0DTE and ATM own the word “gamma”
Gamma scales with how little time is left and how close the strike is to spot. Same-day options are both. A modest pile of 0DTE can out-shove a fat monthly parking lot far from the market. That’s why GEX and open interest disagree on 0DTE days: fewer tickets, more Greek per ticket.
It is also why “gamma” in YouTube titles usually means short-dated. Fine. Just don’t forget monthlies still have gamma. Expiry week, the monthly *becomes* short-dated. The Greek didn’t change species. The clock did.
IV matters too. Higher implied vol smears delta (and gamma) across strikes. A vol crush after earnings can kill gamma on the same OI. The contracts didn’t vanish. The bend did. GEX moves. Max pain, which ignores gamma, doesn’t. Different toys — see max pain vs GEX.
Charm and vanna are the next Greeks in the textbook: delta leaking with time, delta leaking with vol. Real desks care. This site’s Learn cluster stops at gamma because that’s what the chart stacks. If a thread starts “vanna squeeze,” you’re in a different essay. Come back when you can explain gamma on one contract without a screenshot.
American vs European, dividends, the 100 multiplier — they change the *number* on a sheet. They don’t change the idea: bend versus slope. US equity options on the tab are the listed vanilla chain. Don’t import a futures-options footnote onto SPY and then argue with the bars.
From one contract to a GEX chart
Take every listed strike. Guess dealers are on the other side of the open interest. Multiply by gamma (and the usual notional scaling). Stack the bars.
+Gamma bars: the model says the book is long gamma there. Absorber neighborhood.
−Gamma bars: short gamma. Fuel neighborhood.
ABS GEX: how loud, ignoring sign.
Gamma flip: where the *net* stack changes sign. Regime line for the mix of expiries you summed. Not a buy stop. Details in positive vs negative gamma and call wall / put wall / gamma flip.
The Greek on one option is math. The stack is a model plus a chart. People skip the first and argue about the second. Then they’re surprised when a thin name’s “gamma” bar is three thousand contracts.
A gamma squeeze is not the Greek. It’s a *loop* that can start when short-gamma hedging buys a rally. Weather versus storm: gamma squeeze vs GEX.
What gamma is not
It is not a direction. Long gamma is not bullish. Short gamma is not bearish. Sign is about how the hedge leans relative to the last tick.
It is not vega. Vega is how the option price moves when implied vol moves. Related (vol changes the curve, which changes gamma), not the same Greek.
It is not a trading signal. “I’m long gamma” is a position. “The chain is long gamma” is a GEX sentence. Neither says click buy.
It is not max pain, not a call wall, not SPY. Those are applications. This is the bend.
How this shows up on our Gamma tab
You don’t get a per-contract gamma ladder. You get the stack: profile, seven levels, expiry filter. Cyan and red are the Greek piled up. Tap Max +Gamma / Max −Gamma if you want the sentence.
The volatility smile is the *other* chart: IV by strike, not gamma by strike. Don’t mash them. Smile is the price of insurance. GEX is the shove of the book.
Guests see a delayed snapshot. Gamma of 0DTE moves fast. Delay matters. A free account keeps a journal and one full report. Pro is unlimited tickers, not a secret Greek. Single names: the Greek is true, the stack is noisier than SPY.
A short way to remember it without a playbook
- Delta is the hedge ratio now.
- Gamma is how fast that ratio goes stale.
- Loudest near ATM and expiry — that’s why 0DTE dominates screenshots.
- GEX is that Greek stacked with a dealer guess. Then stop.
If those four are boring, good. Boring is the point. You wanted the word. You got the word. The map is next door.
Also in this series: what GEX is, positive vs negative gamma, how to read a GEX chart, gamma squeeze vs GEX.