The Call Wall is the strike with the largest net positive Gamma in the underlying stock/ETF.

Why does Call Wall matter?

It can act as resistance, indicating where sellers may enter the market.

How to use a Call Wall

The Call Wall level lets you know where support lies for a stock, and a change in the price of the Call Wall can help you can manage your risk while either long or short.  A shift higher is often a bullish signal while a shift lower in the Call Wall is a bearish signal.