Two features of the dealer map look like “the day's range,” and traders conflate them. The expected move and the gamma walls are both boundaries, but they answer different questions.

The expected move: what vol implies

The expected move is the ±1σ range the options market is pricing, derived from implied volatility (essentially the at-the-money straddle). It's a statement about how far price is likely to travel — a probabilistic envelope, symmetric around spot, driven by how much movement the market expects.

The walls: where hedging resists

The call and put walls are where gamma concentrates, so they mark where dealer hedging is likely to resist or support price. They're not about how far price can go; they're about where specific levels will push back. They're often asymmetric around spot and tied to particular strikes, not to a volatility estimate.

The expected move says how far the day can travel. The walls say where it'll hit resistance. Distance vs levels — two different maps of the same range.

Reading them together

The interplay is the edge. When a wall sits inside the expected move, it's a very realistic target/fade — price can reach it and the hedging will defend it. When a wall sits outside the expected move, reaching it would require an above-average move, so fading toward it is lower-odds and breaking to it is a bigger deal. And when the expected-move edge and a wall coincide, you have a doubly-defended boundary. Frame every wall against the expected move, and you stop confusing “there's a level there” with “price can realistically get there.”