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Definition · updated 2026-10-21
Open interest
Open interest is the number of option contracts that exist and have not been closed or exercised, reported once a day by the OCC. Volume is today's trades; open interest is the standing position. Volume above open interest on a strike means new positions are being opened, which is the first check on any unusual print.
See it live: today's max pain by ticker.
Why it drives everything on this site
GEX, DEX, max pain and the walls are all open interest weighted by a Greek or an intrinsic value. A strike with huge volume and little open interest is a day trade; a strike with huge open interest is a hedge that has to be managed, which is what moves the tape.
Frequently asked questions
- Is high open interest bullish?
- Not by itself. High call open interest above spot is a call wall that resists rallies; high put open interest below spot is a put wall that supports dips. Direction comes from whether the positions were bought or sold.
- When is open interest updated?
- Once a day, before the open, for the previous session. Intraday prints show up in volume first and in open interest the next morning.