Open interest is the total number of option contracts currently outstanding at a strike — positions that have been opened and not yet closed. It updates once a day, unlike volume, which counts every trade in real time.
OI tells you positions exist; it does not tell you whether the holders are long or short them, or bullish or bearish. It's most useful for spotting where big standing positions sit — the strikes that anchor levels like gamma walls and max pain.
Related terms
- Volume / OI ratio — Today's option volume vs standing open interest. A high ratio suggests fresh positioning.
- Gamma wall — A strike with a large pile of dealer gamma. Call walls often act as resistance, put walls as support.
- Max pain — The strike where the most options expire worthless. A rough magnet level near expiration.
See it in the flow
Open the dashboard to watch real options flow free, or read the beginner guides. Watch-only — not financial advice.