Call wall

Also called Call gamma wall, gamma resistance, call resistance

The strike with the largest positive net dealer gamma exposure in the chosen expirations.

The call wall is the strike holding the most positive net gamma exposure: calls and puts at the strike together, from the dealer's side. Ties go to the strike nearest spot. If no strike has positive net GEX, there is no call wall.

How to read it

Positive gamma at a strike means dealers' hedging there sells into rallies and buys dips. The heavier it is, the more hedging a move through that strike would meet, which is why traders often read the call wall as resistance and expect price to slow or stall as it approaches, especially close to expiration. It's a tendency. A wall can break, and it can move to another strike from one snapshot to the next as price and open interest change.

The call wall can sit below spot as well as above it. The key-levels strip shows its distance either way.

Net, not calls alone

Theta Vantage uses net GEX, so a strike where large matched call and put open interest cancel (common at round index strikes) doesn't become a wall on size alone.

Where it appears

The green rule on the price chart and exposure by strike, the strip, and the Levels card. The strike selector uses the picked expiration's own call wall when it scores a call strike "beyond the call wall", and wheel and income can pick covered calls at or beyond it.