Open Interest (Options)

Open interest (OI) on an options venue is the total number of contracts that currently exist and haven’t yet been closed, exercised, or expired. It’s a snapshot of live, outstanding exposure — how much risk is actually sitting on a venue’s books right now — which is a different measurement from trading volume, which counts activity over a period (say, the last 24 hours) rather than what’s currently outstanding.

A venue can show high volume with low open interest (lots of short-lived positions opened and closed quickly) or lower volume with high open interest (positions opened and held). Neither number alone tells the whole liquidity story, which is why our onchain options reviews reference both where public data allows, instead of citing a single figure as if it fully describes a venue.

Open interest is also a rough proxy for how much collateral writers have posted against outstanding contracts — a useful, if imperfect, signal for how much real capital is backing the positions on a given venue, versus how much is purely speculative churn. See The Complete Guide to Onchain Options for how OI, premium volume, notional, and TVL differ and why they shouldn’t be compared interchangeably. This is a distinct concept from perpetual futures open interest, which measures outstanding leveraged notional rather than a count of options contracts.