Glossary term
Open Interest
The total number of outstanding option or event contracts not yet closed or settled; a liquidity and positioning indicator.
Open Interest is the total number of outstanding contracts that have not yet been closed, exercised, or settled. It is a primary liquidity indicator: high open interest means tighter spreads and easier exit, while thin open interest signals execution risk. The metric applies to both options chains and prediction-market contracts, where it gauges how much real capital sits behind a price. See Prediction Market Risk 101.