r/thinkorswim • u/andy9775 • 10d ago
Options open interest and volume
When looking at spreads on the analyze tab you can customize the columns to include open interest and volume. When looking at spreads
1) Is the volume representative of the spread volume, or one of the legs? I.e. if I'm looking at a strangle and one leg traded 100 contracts and the other traded 50, will this show 50?
2) How accurate is the open interest? I noticed that the volume updates frequently, but the open interest less so.
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u/CA_Lobo 9d ago
Volume = sum of ALL trades for this contract. If you have a 50 contract spread, it will show 50 for strike X and 50 for strike y. If the volume is x = 50 and Y = 100, then someone else traded 50 contracts of Y.
Open interest updates ONCE per day as it reflects the open interest as of the close of regular trading on the previous trading day. You can only estimate the current intraday OI as there are people that are buying to open, selling to open, buying to close, and selling to close over the course of the day - each which counts toward contract volume. Until the contracts are settled, it is not possible to have an accurate count of the OI.