What options volume measures
Option volume increments when contracts trade. If one buyer and one seller transact 100 contracts, the market records 100 contracts of volume—not 200. The same contracts can trade again later, adding more volume even if the number of positions remaining open at day end does not change.
High volume indicates attention and liquidity during that session. Its meaning depends on the contract’s normal activity, spread, underlying and catalyst. Ten thousand contracts can be extraordinary in one chain and routine in a major index option.
What open interest measures
Open interest is the number of outstanding contracts after positions are matched and cleared. It rises when both sides create new exposure, falls when both sides close existing exposure and can remain unchanged when an opening trader transacts with a closing trader.
Published open interest normally represents the prior clearing cycle rather than a live intraday count. That timing difference is why today’s flow should not be compared with OI as though both values describe the same instant.
- Opening buyer plus opening seller: open interest increases.
- Closing buyer plus closing seller: open interest decreases.
- Opening trader plus closing trader: open interest is unchanged.
- Intraday volume accumulates regardless of the final open-interest result.
Does volume above OI mean new positions?
It means current-session trading has exceeded the previously reported open contracts. That can make the contract worth investigating, especially when volume is concentrated in large, aggressive prints. It does not prove that the entire volume created new positions because contracts may change hands several times and some traders may be closing.
The next day’s open-interest change can add evidence, though it still cannot assign intent to individual prints. Combine volume and OI with bid/ask execution, premium, repeated flow, liquidity and related contracts before drawing a directional conclusion.