Call Wall and Put Wall: What They Mean

By The Oracle · For education, not financial advice.

The call wall is the strike above the current price with the largest positive gamma exposure, and the put wall is the strike below it with the largest negative gamma exposure. They mark where dealer hedging is estimated to be heaviest. The call wall is often read as resistance, because dealers are assumed to sell stock into strength there. The put wall is often read as support, but that read is shakier: hedging around a heavy put strike can add to a fall once it breaks. Both rest on an assumption about who holds the options, and both move as positions change.

How the walls form

Every strike carries some gamma exposure: gamma × open interest × 100 × price² × 0.01, in dollars per 1% move. What is GEX? walks through the formula. Under the usual convention, dealers are assumed to be long the calls customers sold them and short the puts customers bought, so call gamma counts as positive and put gamma as negative. Then rank the strikes:

• Call wall. The largest positive strike above the price.
• Put wall. The largest negative strike below the price.

Definitions vary. Some providers rank by open interest, some by gamma, some by net gamma after calls and puts at the same strike offset each other, and some smooth across neighbouring strikes. That is why two tools can show different walls for the same stock on the same day.

Why a call wall can act as resistance

If dealers are long a large block of calls at a strike, then as price rises toward it, those calls’ delta rises fastest near the strike. To stay hedged, dealers sell stock into the rally, and the heavier the block, the more each step up requires. So a rally can stall near the strike. The same logic works on a dip, when dealers buy stock back and cushion the fall. A stock between a large call wall and a broad positive area below it can trade in a tight range for days.

Why a put wall is a weaker floor

Under the convention, the put wall is where dealers are most short gamma, and short gamma hedging runs the other way: as price falls toward the strike, dealers sell more stock, and as it rises, they buy. A heavy put strike can still slow a decline for a while, for example when put holders take profits there. But once price breaks through, hedging tends to speed the move up rather than stop it. That is why many traders treat a clean break of the put wall as more telling than a touch.

A worked example

The call wall is $105, the largest positive strike above $100. The put wall is $95, the largest negative strike below. Between them sits a $10 corridor where, under the assumption, hedging leans against moves near the top and starts to add to them below about $97.50, the estimated gamma flip.

Suppose XYZ rallies to $104.80 and stalls twice. That fits the call wall reading, though it proves nothing on its own. Suppose instead it drops through $95 on heavy volume: the put wall reading says expect the move to run, not to bounce. And if the $105 calls turn out to have been bought by customers, dealers are short them, the +$8M is really negative, and the wall may give way rather than hold.

Walls move

• Expirations. Walls built from a near-term expiration vanish when it expires. They often carry the most weight in the days before a large expiration and the least right after it.
• New positions. Heavy trading at a strike reshapes it when open interest updates overnight.
• Rolls. Traders who roll a position to another strike take the wall with them.
• Price. Once price moves past a strike, it can stop being a wall at all.

Re-read the walls each morning, and again after any large expiration.

How to use the walls

• Use them to frame a likely range, not to set an exact target.
• Check the regime first: walls behave differently in positive and negative gamma.
• Watch behaviour at the level: a stall, or a clean break on volume.
• Check the flow. Heavy buying at a wall strike can change it overnight; options flow vs GEX explains how.

Walls in MomoEdge

MomoEdge’s GEX tab marks the call wall as Wall and the put wall as Support for one ticker at a time, with the gamma flip between them. The GEX tab lesson shows each level on screen. The $10K account shows every trade our team takes with real money, winners and losers, before commissions and fees. If you want to follow the walls on live data, you can see what the terminal includes.

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