The dealer map marks the call wall as a level, but the underlying reality is a distribution of gamma across strikes. Often the largest concentration sits at one clear strike. Sometimes several adjacent strikes each carry heavy gamma — a stacked wall, a thick band of resistance rather than a single line.
A zone, not a line
When high-gamma call strikes cluster (say 745, 746, and 747 all loaded), price doesn't face one pin — it faces a wall of pins. Each strike adds hedging resistance, so the whole band tends to absorb and stall price across a range, not just at a single number. Treating it as one thin line under-reads how much overhead supply is really there.
A single call wall is a fence. A stacked wall is a hedge-row — price has to grind through several strikes of resistance, not hop one line.
Why it pins harder
More stacked gamma means more mechanical hedging leaning against advances through the zone, so a stacked wall generally holds better and pins longer than an isolated strike. It's a stronger fade zone in positive gamma — and, correspondingly, a more meaningful signal if price manages to break decisively through the whole stack, because it took real demand to clear that much resistance.
How to trade it
Treat a stacked wall as a target zone and a fade band, not a precise line: expect stalling and chop as price works into it, and don't demand a reaction at one exact tick. Size and time your fades to the zone. And respect that clearing an entire stack is a stronger continuation signal than popping a lone strike. Reading the wall as a distribution — which a gamma-weighted map shows — is what turns “resistance is near” into an actual plan.