Most losing days come from trading the wrong kind of day — fading a market that wants to trend, or chasing one that wants to chop. The good news: dealer positioning tells you which kind of day you're likely in before the first candle, through one reading — the sign of net gamma.
Two kinds of day
A range day grinds, pins, and mean-reverts — extremes get sold, dips get bought, and price rotates inside a band. A trend day extends — moves feed on themselves, pullbacks are shallow, and fading is punished. Almost every session leans one way or the other, and the lean is largely set by how dealers are positioned.
Positive gamma = range
When net gamma exposure is positive, dealers hedge against the move — selling strength, buying weakness — which dampens price. That's your range day: respect the walls, expect fades at the extremes, and treat the expected-move band as the container (positive vs negative gamma).
Negative gamma = trend
When net gamma is negative, dealers hedge with the move — selling into weakness, buying into strength — which amplifies it. That's your trend day: moves extend, walls break instead of holding, and fading the move is the losing side. The posture flips from “sell the edges” to “don't stand in front of it.”
You don't need to predict direction to win the day. You need to know whether to fade or follow — and the gamma sign tells you that.
Reading which one you're in
Two inputs. The sign of net GEX is the headline — positive leans range, negative leans trend. Then where price sits relative to the gamma flip refines it: comfortably in positive territory is a clean range day; hovering just above the flip with momentum down is a range day that could change character.
The costly mistake
The single most expensive error is fading a negative-gamma day — selling strength into a market built to extend it. If the regime is negative and price is below the flip, that “overbought” push is exactly the one you don't fight. Read the regime first; it's the frame every other decision hangs on, and it's the first line of the full dealer-positioning read.