Open Interest (Options)
The total number of outstanding (unclosed) option contracts at a given strike and expiry. Rising OI confirms new money entering; it gauges liquidity and where positioning is concentrated.
Open interest (OI) is the count of all option contracts that have been opened but not yet closed, expired, or exercised at a specific strike and expiration. Unlike volume (which resets daily), OI is a cumulative running total.
Rising OI alongside price movement confirms that new money is entering the market and supporting the move. Falling OI on a price move suggests existing positions are closing — a less convincing signal. High OI at a particular strike can act as a gravitational level into expiry.
OI is also used to assess liquidity: strikes with high OI typically have tighter bid-ask spreads and are easier to fill in size. Very low OI strikes may be difficult to exit without significant slippage.
Related Terms
Expiration Date
The last date on which an option can be exercised; after this date the contract ceases to exist.
IntermediateImplied Volatility
The market's forward-looking expectation of volatility, derived by solving the options pricing model for the volatility that matches the observed premium.
AdvancedOptions Chain
The quoted matrix of all available calls and puts for a given underlying, organized by strike and expiration date, showing bid/ask, IV, volume, and open interest.
BeginnerStrike Price
The fixed price at which the option holder can buy (call) or sell (put) the underlying asset if they choose to exercise.
Beginner