Gamma, Pins and Max Pain, Translated
Macro is not microstructure
Start here, because the confusion is the point. Macro is about the price of money and the cost of credit: policy rates, yield curves, the liquidity of the system, who can refinance and who cannot. Its horizon is weeks to quarters, and its output is a direction. It answers: is there a reason for this to move?
Microstructure is about the positions people already hold and the hedges attached to them: which strikes carry the most open interest, when they expire, and what forced flow appears when the underlying moves. Its horizon is hours to days, and its output is a path. It answers: if this moves, how does it travel?
The two are not competitors and neither is superior. A rates trader who ignores the curve to read option positioning is guessing at the weather from the wind. A macro reader who dismisses positioning as noise is ignoring the reason a move arrives in three hours instead of 3 weeks. What matters is not confusing a path for a level, or a level for a path.
An option is a promise with a hedge attached
A call option gives its buyer the right to buy at a fixed price; a put gives the right to sell. The seller of that option - usually a dealer or market maker - has accepted an obligation, and to keep the position flat they hedge it by trading the underlying.
The amount they need to hold is called delta. The speed at which that amount changes as the price moves is called gamma. Gamma is the whole story here: it tells you how much forced trading a given price move creates, and in which direction.
Near-the-money options have the most gamma - an option that is exactly at the strike flips between in and out of the money constantly, so the hedge has to be adjusted constantly. Deep out-of-the-money options barely move the needle. That single fact explains why a 'max gamma' strike sits near the current price rather than at the strike with the most contracts outstanding.
The pin, and why price sticks
When a large amount of open interest sits at one strike, dealer hedging tends to dampen moves around it: as the price falls toward the strike they buy, and as it rises away from it they sell. The result is that the market behaves as though it is magnetised to that level. That is a pin.
It is not a prophecy and it is not a conspiracy. It is mechanical: a pile of hedges that all want to fade the same move. It also has a shelf life. When those options expire, the hedges that produced the pin are released, and the magnet switches off - which is why the days after a large expiry can feel like a different market for reasons that have nothing to do with the news.
The sign of dealer gamma matters more than the size
If dealers are long gamma - typically because customers have sold them options - their hedging leans against the move. Volatility compresses and prices pin. If dealers are short gamma, the hedging runs the other way: they must buy as the price rises and sell as it falls, which amplifies whichever direction the market is already going.
'Dealer GEX' is the aggregate of that exposure, and the common shorthand is that a large negative number means the market's plumbing is pro-cyclical and unstable, a large positive number means it is self-damping. When you read that negative dealer gamma is about to halve because positions are expiring, the correct translation is: the amplification is being switched off, so the market should become quieter - not louder.
One caution that applies to every number in this dialect: GEX is not published by anyone. It is estimated from open interest plus an assumption about which side of each trade the dealers are on. The strikes and the expiry dates are facts. The positioning is a model.
What this week's expiry actually looks like
Here is the 25 September Bitcoin options expiry, drawn from Deribit's own published book summary. Calls are above the axis, puts below, and the green dashed line is spot. Two things are worth reading off it.
First, the largest open interest is not near the price: it sits at $70,000, with 15,790 BTC of combined open interest - roughly 8,100 calls and 7,700 puts. There is a second shelf at $90,000 to $100,000, where call open interest clusters, and a third in the put wing at $60,000.
Second, that is not where the most gamma is. Gamma concentrates near the money, and spot was around $84,300 when this snapshot was taken. So a commentary that names $85,000 as the max-gamma strike and $70,000 as the largest open-interest strike is not contradicting itself - those are two different measurements, and knowing which one a writer is quoting is most of the work of reading them.
The whole expiry held about 171,500 BTC of open interest across 70 strikes when this was drawn - 93,500 in calls and 78,000 in puts. That number is a fact. What dealers are hedged against is not.
Opex, and the 'max pain' story
Opex is just expiry day. In crypto options the significant one is the last Friday of each month, which is why the share of total open interest expiring on a single afternoon can be enormous - half the book in 1 session is normal, not a signal.
Max pain is the claim that price tends to gravitate toward the strike where the most option contracts expire worthless, because that is where the sellers of those options pay out the least. It is a popular idea and a weak one: it is derived from the same unverifiable positioning data, it has no mechanism that would force spot to a level, and its apparent record is largely the result of people pointing at the expiries where it worked.
Treat it as folklore that occasionally rhymes with the tape, not as an input. If you cannot state what flow would have to happen for it to be true, it is a story rather than a mechanism.
The post this lesson decodes
The example that prompted this lesson is this one, published on 24 September 2026 - $BTC: the $85K wall is about to change. In plain English: about half of the options exposure in Bitcoin expires, including part of what has been pinning price near $85,000; the amplification that has been running in the background weakens with it; and above $85,000 the option structure is thin enough that $90,000, $95,000 and $100,000 could travel quickly if real buying appears.
His closing line is the honest part, and it is why this belongs on a macro site at all: the derivatives market can amplify a move, it cannot create the demand that starts one. Structure gives you the multiplier, never the reason.
One detail worth checking rather than repeating. He cites 29,003 contracts of call concentration at $90,000. Our own pull of the 25 September expiry shows 7,137 BTC of open interest at that strike - so his figure is either a different expiry, a different venue, or a different unit. That is not a contradiction, it is an unanswered question, and the answer changes what the number means. Ask before trading off it.
What to take from it, and what to ignore
Take the mechanics: gamma concentrates at the money, hedging can pin a market and then release it, and expiry changes the plumbing on a date you can put in a calendar.
Ignore the implied authority. Every positioning number you will read in this dialect is an estimate built on an assumption, published with more confidence than its error bars deserve. The verifiable parts - strikes, expiries, open interest, the published book - are enough to reason with. The rest is a hypothesis about who is on the other side, and it is worth exactly as much as the assumption behind it, which is never shown.