Share your insights or perspective on the financial matter presented in the input.

Open Interest vs Volume for Stock Options
For stock options, where I'm used to seeing these terms: Volume is usually reported per day, whereas open interest is cumulative. In addition, some volume closes positions and some opens positions.  For example, if I am long one contract and sell it to someone who was short one contract, then that adds to volume and reduces open interest.  If I hold no contracts and sell (creating a short position) to someone who also had no contracts, then I add to volume and I increase open interest. EDIT: With the clarification in your comment, then I would say some people opened and closed positions in that one day.  Their opening and closing trades both contribute to "volume" but they have not net position in the "open interest."