Call Wall and Put Wall Explained
The Call Wall is the strike with the most call gamma, and the Put Wall the strike with the most put gamma, across the options that are still open. Both are round prices where dealers would need to hedge the most. Price often hesitates near them, which is why they are drawn like support and resistance.
On this page
What are the Call Wall and the Put Wall?
A call gives its owner the right to buy at a fixed price (the strike); a put gives the right to sell at a strike. Each option has a gamma, the speed at which its price sensitivity changes. The word "wall" comes from what the gamma profile looks like: a tall pile of exposure sitting on one round number.
The Call Wall is usually above the current price, where traders have bought or sold most calls. The Put Wall is usually below, where puts are concentrated. For the bigger picture of what these numbers measure, see What is gamma exposure.
How are they found?
The model takes every open contract, computes its dollar exposure and adds it up strike by strike:
Exposure ≈ gamma × open interest × 100 × price² × 0.01
Then it picks the strike with the largest total among calls (the Call Wall) and among puts (the Put Wall). A large open interest (how many contracts are still open) at one strike is what creates most of the height. Because gamma of at-the-money options is larger, a strike right next to the current price can outweigh a much bigger pile of far-away contracts.
How do you read them?
- Call Wall above price: price moving up into it often slows, because hedge selling increases. A clean break through it means that flow was absorbed.
- Put Wall below price: in positive gamma, hedge buying near it can support price. Below the Zero Gamma, a break of the Put Wall is where hedging can start pushing with the move.
- Distance to each wall gives a rough sense of the range the option book describes today. It is a description of conditions, not a target.
What does it look like with numbers?
An index trades at 5,000. Gamma per contract at the nearest strikes is about 0.0001 per point, so each contract carries 0.0001 × 100 × 5,000² × 0.01 = $2,500 of exposure per 1% move.
Calls: 15,000 open at 5,050, 6,000 at 5,100, 2,000 at 5,150. The Call Wall is 5,050 (+$37.5 million).
Puts: 12,000 open at 4,950, 8,000 at 4,900. The Put Wall is 4,950 (−$30 million).
Read in plain words: today the option book is heaviest 50 points above and 50 points below price. If price leaves that band, the next piles are much smaller.
What are the limitations?
- They come from a model. Gamma is computed from an assumed volatility and time to expiry; another setting can move a wall by a strike.
- We do not know who bought or sold. A large position held by one fund can dominate a wall and may hedge differently than a dealer.
- Open interest is published with a delay. Today's new contracts only show up in tomorrow's number.
- They do not predict price. Walls describe where hedging is concentrated; price can go through them, or stop well before them. See common mistakes.
See it on the chart
GexFlow draws the Call Wall and the Put Wall as two labeled lines on your chart, above and below price, and you can open the gamma-by-strike table to see which strikes make each one. Every line has a short note explaining how to read it.
Risk disclosure: GexFlow is an analysis and education tool operated by House Genius LLC. It does not provide investment advice, does not manage money and does not give buy or sell signals. Levels, indicators and statistics describe market conditions and do not predict prices. Trading options involves substantial risk of loss and is not suitable for every investor. Market data may be delayed or inaccurate. © 2026 House Genius LLC.
GexFlow team · Last updated: 2026-10-22 · Pending expert review
Keep reading: What is gamma exposure · Zero Gamma explained · Options Greeks for beginners · See GexFlow pricing.