Two staples of the dealer map trace back to one flow. Put/call skew — puts costing more than equidistant calls — and the put wall — the gamma-supported floor below price — are both fingerprints of the market's persistent appetite for downside protection.
One flow, two footprints
Investors continually buy puts to hedge, which does two things at once. It bids up put implied volatility relative to calls — that's the skew, the price of fear. And it concentrates open interest (and therefore gamma) at popular protection strikes, where dealers end up short those puts — that's the put wall, the floor dealer hedging defends. The demand for protection shows up in the option's price (skew) and in the structure it builds (the wall).
Skew is the cost of protection; the put wall is where that protection piles up. Same buyers, two readouts.
What a steepening skew tells you about the floor
Because they share a source, they move together in informative ways. A steepening skew — protection demand rising — often means more put open interest building, reinforcing or lowering the put wall as new protection strikes load up. A flattening skew — complacency, or an upside chase — can mean a thinner, less-defended floor. Watching skew is a leading read on how strong the put-wall support is likely to be.
How to use the pair
Read them as one signal from two angles. A firm put wall backed by a steep, steepening skew is a floor with conviction behind it — a higher-quality bounce zone in positive gamma. A put wall sitting under a flattening skew is a floor to trust less. Combined with the regime, this is a richer read than either the level or the vol number alone — exactly the kind of multi-angle picture the full dealer read is built to give.