What is Call Open Interest? This is the total number of calls outstanding as of the close of business yesterday. Why does Call Open Interest matter? The number of calls indicates how much investors believe in the market. This is not a proprietary SpotGamma metric and should be compared to the CP Gam Tilt and other SpotGamma Key Levels such as the Call Wall. How to use Call Open Interest This is simple a tracked metric that lets you know how many calls are outstanding, and therefore, how much speculation exists in the market. We would advise learning to use the Call Wall, Vol Trigger, and daily range. Related articles What is a Gamma Profile? What is a Call Wall? What is Put Open Interest? What is 25D Risk Reversal? What is Put Volume?