What Is a Call Wall? Options Resistance Explained
A call wall is the strike most likely to stop an advance, and the level most worth marking before a session begins.
What is a call wall?
A call wall is the strike carrying the largest positive gamma exposure above the current price. As price rises toward a call wall, dealers who are long gamma sell the underlying to stay hedged, and that selling creates mechanical resistance without any fundamental seller being involved.
Why does a call wall act as resistance?
Resistance at a call wall is a hedging artefact rather than an opinion. Dealers long gamma must sell as price rises to keep the book neutral, so every advance toward the wall is met with supply that grows heavier the closer price travels to the strike itself.
When does a call wall break?
A call wall breaks when order flow overwhelms the hedging supply, most commonly on a news catalyst, an index rebalance, or after the open interest at that strike has been rolled away. A wall that shrank overnight is far weaker than the raw strike number suggests.
How does the Obsidian desk trade a call wall?
The Obsidian desk treats a call wall as a target rather than an entry. Longs taken below the wall aim into the wall, and the desk only fades price at the wall once the tape confirms rejection, because an unconfirmed fade at a breaking wall is the worst available trade.
Frequently asked questions
Is the call wall the same as the highest open interest strike?
Not necessarily. The highest open interest strike ignores gamma, which varies with time to expiration and moneyness. A nearer expiration strike often carries more gamma with less open interest.
Does the call wall move during the day?
The strike itself is fixed, but the gamma concentration at that strike changes as spot travels and as new contracts trade, so the wall can strengthen or weaken within a single session.