Dealer positioning

What is a call wall and a put wall in options trading?

A call wall is the strike with the most call gamma, usually above price. A put wall is the strike with the most put gamma, usually below it. They mark where options hedging is heaviest, which is why traders watch the call wall as resistance and the put wall as support. Whether they actually hold depends on who is on each side of those options.

How a call wall and put wall are found

Every strike carries some gamma: the open interest there, times how sensitive each contract's delta is to price. Add it up per strike and two strikes stand out. The call wall is the one with the most call gamma, and the put wall is the one with the most put gamma. Most tools also show the next two (CW2, CW3, PW2, PW3). They move during the day as open interest and fresh trades change the book, and they reset as expiries roll off.

On its own a wall only says a lot of options sit here. It doesn't say who bought them and who sold them, and that decides what the hedging does.

When a wall holds: dealers long gamma

If dealers own the options at that strike (someone else sold them), they are long gamma there. To stay hedged they sell as price rises into the strike and buy as it falls back. That leans against the move, which is the case for a call wall acting as a ceiling and a put wall acting as a floor. Strikes where traders sell options for income, or the short leg of big collar trades, tend to work this way.

When a put wall is a trapdoor: dealers short gamma

Most put open interest is bought for protection, so the dealers on the other side are usually short those puts. Short puts are long delta, so dealers hedge by selling futures, and as price falls toward the strike the puts gain delta and they have to sell more. On the way in, that hedging pushes the drop further, not back.

So why do put walls still bounce so often? Three things happen at the strike itself:

The selling peaks and runs out. Gamma is biggest at the strike; once price is through, there is less left to hedge, so the forced selling fades right around the wall.
Put buyers cash in. Price reaching a big put strike is when those holders take profit, and dealers buy back the futures they sold as a hedge. That buying is the bounce.
Time and volatility. As time passes or implied volatility drops, the puts lose delta and dealers slowly buy back hedges (charm and vanna).

That is the familiar pattern: a flush into the put wall, then a bounce.

Who is on each side	As price moves into the wall, dealers…	Effect
Dealers long the options (traders sold them)	trade against the move	Support or resistance
Dealers short the options (traders bought them)	trade with the move	Acceleration into the strike, often a bounce once through

Is a put wall support? What our data says

We tested the walls on every recorded session from 28 September to 9 October 2026 across SPX, SPY, ES, NDX, QQQ, NQ and IWM, counting a hold when price came 10 basis points back off the level before going 5 through it within an hour. The #1 put wall held 39% of the time against 37% for random prices; the #1 call wall 34% against 37%. On their own, walls were not better than random. They mark where hedging is heaviest, and something often happens there, a bounce or a run straight through; which one is what order flow at the level tells you.

One level did better than chance in the same tests: the most positive net-gamma strike within 1% of price held 46% of the time against 38% for random prices. That is the long-gamma case above.

How Zanshin Flow shows them

The walls are tagged on every chart's price scale (CW1 to CW3, PW1 to PW3) as they stood each minute, and mapped onto ES and NQ futures prices for index symbols. The Walls window grades each one and estimates the dealer side (long or short gamma), the thing that decides which case above you are in. Read more on gamma exposure, the gamma flip and dealer hedging.

NDX absolute gamma in NQ prices with the call and put walls, the Walls window and the Wall Map, in Zanshin Flow — NDX walls on NQ prices: graded in the Walls window and traced through the day on the Wall Map.

Questions

What is a call wall?

The strike with the most call gamma in the options market, usually above price. Traders watch it as resistance because, when dealers are long those calls, their hedging sells into rallies toward it.

What is a put wall?

The strike with the most put gamma, usually below price. It is watched as support because, when dealers are long those puts, their hedging buys declines into it.

What is a call wall in options trading?

A level where call open interest and gamma are concentrated. It shows where options hedging is heaviest above price; it is a reference level, not a guaranteed ceiling.

Is a put wall support?

Sometimes. If dealers are long the puts there it tends to act as support. If they are short them (traders bought the puts for protection) their hedging sells into the drop, and the bounce usually comes once the strike is reached and put buyers take profit. In our data the #1 put wall held 39% of the time against 37% for random prices.

Is a call wall resistance?

Not reliably on its own. In our tests the #1 call wall held 34% of the time against 37% for random prices; it marks heavy hedging, not a guaranteed turn.

What happens when price breaks a put wall?

If dealers were short those puts, their selling fades once price is through the strike, and put holders often take profit, so a bounce can follow. If price keeps going, the next put wall below becomes the reference.

How is a call wall calculated?

For each strike, open interest times gamma (often in dollars per 1% move), summed for calls; the call wall is the strike with the largest total. The put wall is the same for puts.

Not financial advice. This article explains how options and dealer hedging work. It is not a recommendation to buy or sell anything.