On the 30 Jun 2026 chain, traded volume bunches at a few round strikes and thins out between them
Volume and open interest are both counts on an option chain, but they measure different things. Volume is the number of contracts that changed hands in the session. Open interest is the number of contracts still open at the close, meaning positions that have neither been closed out nor expired.
A trade can add to volume without changing open interest. When an existing holder sells to a new buyer, the contract trades, but no new position opens. A strike can therefore show heavy volume on a day when its open interest barely moves, and the reverse happens when positions are carried over without much trading.
The units differ, and this is where most mistakes start. NSE publishes open interest in units and volume in contracts. One Nifty contract is 65 units, so open interest has to be divided by 65 before it sits beside volume. Compare the two only after both are in contracts.
The chart shows volume on the 30 Jun 2026 Nifty chain as it stood on 10 Jun 2026. Trading bunches at a few round strikes near the money and thins out between them. Across the whole chain, the strike with the most open interest sat well above the money, away from the busiest strike. Volume follows where the day's trading happened, and open interest follows where positions have built up, so the two maps can disagree.
Use volume to judge how active a strike was and whether a price move had trading behind it. Use open interest to judge how many positions carry into the next session. The build up patterns show how open interest and price work together, and the open interest page sets out the units.
Before you trade. Derivatives trading carries a high risk of loss. SEBI's study "Profitability of Individual Traders in the Equity Derivatives Segment (FY25 to FY26)" (August 2026) found that 87.7% of individual traders in equity F&O made net losses in FY26, with aggregate net losses of Rs 91,685 crore. Read the SEBI study