--- title: "Open interest, volume and build up patterns, NSE" description: "What open interest counts, how it differs from volume, and what long build up, short build up, short covering and long unwinding can and cannot say." source_url: "https://www.rupeecase.com/learn/path-13/module-13-3-open-interest-and-build-ups" --- [Path 13 3 of 7](/learn/path-13/)Open interest, volume and the four build up patterns[Next 13.4](/learn/path-13/module-13-4-futures-rollover) Between Monday 15 Jun and Tuesday 30 Jun 2026 the open interest of the June Nifty future fell on every session until about a quarter was left. Read alone, that looks like longs giving up, or shorts covering. Now look at the July future over the same days: its open interest climbed as steadily as June's fell. Same traders, new contract. I check which contract a number belongs to before I read anything into a fall in open interest. This lesson covers what open interest counts, how it differs from [volume](/learn/glossary#volume), and the four patterns that screens print from the two. Every figure comes from NSE end of day files and is dated, not live. 3By the end you can 1. Say what open interest, change in OI and volume each count, and convert units to contracts. 2. Name the four build up patterns from the price move and the OI move. 3. Explain why a fall in the near month's OI can be a roll and not an exit. Watch in the terminal: what do Placed, Open and Partly filled mean? A short tutorial on sample data. ## The idea, plainly Open interest, or OI, counts the contracts that are still open. Every contract has one buyer and one seller, and the pair counts once. A new buyer meeting a new seller adds one contract. An old buyer and an old seller closing against each other remove one. If one side opens while the other closes, the count does not move. One trade moves open interest up, leaves it alone, or moves it down What counts is whether each side is opening a position or closing one. The count says nothing about which side was right. Source: RupeeCase illustration of how NSE counts open interest. As of 16 Oct 2026. Read 2 more paragraphs, 129 words Volume counts the contracts traded in the day, whatever they did to OI. Think of a car park. Volume is the cars that drove through. Open interest is the cars still parked at night. A day trader who buys and sells the same contract all day adds to volume with every trade and leaves nothing open at the close. Mind the unit. NSE's end of day file counts open interest in units, so each contract adds 65. Many screens count contracts. Volume is in contracts. Convert before you compare. Change in OI is today's OI less yesterday's. Cumulative OI is the OI of every expiry month added together, which on a futures screen means the three monthly contracts. The short answer is on the [open interest question page](/learn/questions/what-is-open-interest). ### The four build up patterns Screens combine two numbers, the day's price move and the day's change in OI, into four labels. | | OI rises | OI falls | | --- | --- | --- | | Price rises | Long build up | Short covering | | Price falls | Short build up | Long unwinding | * **The roll.** The near month's OI falls into expiry mostly because positions move to the next month, not because anyone gave up. * **Hedges and arbitrage.** A fund that holds shares and sells futures against them adds to OI, and on a day the price falls that prints as a short build up, with no view on the index at all. * **Size.** A rise of a few points earns the same label as a rise of a few hundred. The label records the sign of each number, not how large it was. * **Both sides.** Every new contract has a seller as well as a buyer. Price is read as showing which side was keener to trade. OI cannot say who is right. Read one more paragraph, 75 words Each label is a story told from the direction of price. Price up with OI up is read as new buyers. Price down with OI up, as new sellers. Price up with OI down, as sellers closing. Price down with OI down, as buyers closing. The labels describe the day. They are not signals for the next one, and four things can break even the description. The [build up question page](/learn/questions/long-short-build-up) has the short version. ## Worked example: June 2026 and the eve of expiry First the roll. The June future's open interest, in units, at each close from 15 Jun to expiry day, 30 Jun: The June future's open interest fell on every session into expiry Near month Nifty future, open interest in units, from 15 Jun to expiry day on 30 Jun 2026. Divide by 65 for contracts. L is lakh and Cr is crore. Source: NSE end of day data, computed by RupeeCase. As of 30 Jun 2026. Now the same window for the July future. The July future's open interest rose on every one of the same sessions Next month Nifty future, open interest in units, over the same sessions. What June lost, July gained. Source: NSE end of day data, computed by RupeeCase. As of 30 Jun 2026. On expiry eve the strikes near the money traded many times their open interest Show all columnsShow fewer columns | Calls | Calls | Strike | Puts | Puts | | --- | --- | --- | --- | --- | | OI | Volume | Volume | OI | | 4.8L | 94,493 | 23,700 | 30.6L | 71.8L | | 2.6L | 71,271 | 23,750 | 25.2L | 42.1L | | 21.3L | 5.2L | 23,800 | 51.4L | 1.06Cr | | 9.2L | 4.7L | 23,850 | 40.6L | 41.9L | | 33.4L | 21.6L | 23,900 | 80L | 92L | | Spot 23,946.25 | Spot 23,946.25 | | 51L | 37.3L | 23,950ATM | 72.3L | 55.9L | | 1.72Cr | 77.8L | 24,000 | 1.03Cr | 1.2Cr | | 67.1L | 57.2L | 24,050 | 57.8L | 22.4L | | 1.57Cr | 95L | 24,100 | 60.8L | 49.4L | | 70.8L | 48.7L | 24,150 | 17.3L | 8.2L | | 1.38Cr | 54.7L | 24,200 | 15.3L | 27.2L | Shaded cells are in the money. Outlined cells hold the most open interest among the strikes shown. OI is in units and volume is in contracts; L is lakh and Cr is crore. Calls on the left, puts on the right, the strike in the middle, for the Nifty chain of 29 Jun 2026. Volume is in contracts and open interest in units, so divide the OI by 65 before comparing. Source: NSE end of day data, computed by RupeeCase. As of 29 Jun 2026. Read 4 more paragraphs, 237 words A screen that shows only the near month would label every one of those June days long unwinding or short covering, according to the day's price move. Over the same days the next month was filling up. Whoever looked only at June saw a market emptying out. Whoever added July saw positions moving house. [Module F10](/learn/path-13/module-13-4-futures-rollover) follows that move and what it costs. Now volume against OI, on the chain of Monday 29 Jun 2026, the eve of expiry. Take the 24,100 call. It traded 94,99,236 contracts that day. At the close 1,57,43,650 units were open, which is 2,42,210 contracts at 65 units each. Volume was 39.2 times the open count. The open count itself had grown by 1,21,811 contracts, from 1,20,399 the day before, so it roughly doubled and was still a small fraction of the day's traffic. Try the arithmetic on the table. Pick any strike, divide its OI in units by 65 to get contracts, then divide the volume by those contracts. That is the turnover ratio. Do it again for a strike further from the money and compare the two. So which one matters? Volume tells you how busy a strike was, which is liquidity. OI tells you how much is still open and has to be closed or settled. Neither tells you direction. [The question page](/learn/questions/volume-or-open-interest) takes that one to its short answer, and [module F18](/learn/path-15/module-15-2-open-interest-on-the-option-chain) reads OI across a whole chain. 3 terms this section turns on From the module glossary; every term is in the Learn glossary too. Source: Module 13.3, Open interest, volume and the four build up patterns. ## The common mistake The belief: Open interest is rising, so the big players are buying. Look at what rose. On the 24,100 call, OI roughly doubled in a day, and every one of those new contracts has a buyer and a seller. OI can tell you that positions were opened. It cannot tell you which side opened them with a view, which side was hedging shares, or which side will close by lunch. Price direction is doing all the work in the four labels, and open interest only decides which pair of labels you get. Treat a build up as a description of the day and check the contract month before you believe it. ## Key takeaways * Open interest counts contracts still open. Volume counts contracts traded in the day. * NSE's day file counts OI in units. Divide by the lot of 65. * OI changes only when both sides open or both sides close. * The four labels describe the day. They do not signal the next one. * Near month OI drains into expiry because positions roll to the next month. * Hedges and arbitrage count as build ups with no view on the index. Watch in the terminal: what do skew and kurtosis say? A short tutorial on sample data. **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](https://www.sebi.gov.in/reports-and-statistics/research/aug-2026/study-profitability-of-individual-traders-in-the-equity-derivatives-segment-fy25-fy26-_103835.html) What does Open interest, volume and the four build up patterns cover?Open interest counts what stays open. Volume counts what traded. Four labels come from them, and the roll can fake an exit. It works through The idea, plainly, Worked example: June 2026 and the eve of expiry, The common mistake, Key takeaways. It is module 13.3 of Path 13, Futures, about 7 minutes of reading, free. AF&O on RupeeCase ## Hedging only, in development F&O at RupeeCase will do one job: protect a portfolio you already own, by a rule published before it runs. No speculation, no naked option selling, no leveraged bets. It is not available yet. [How hedging will work](/hedging)[Sign up for RupeeCase](https://invest.rupeecase.com/signup) [No hedgeFalls with the marketWith a putA floor, for a premiumIllustration with made up numbers, not a product and not a recommendation.](/hedging) QQuick check ## 10 questions, 7 to pass. Each attempt draws 10 of the 15 questions in this module's bank, and a retake draws a fresh set. A pass gives this module's Certificate of Completion. Your result stays on this device and counts towards the Path 13 certificate. 7 of 10 correct passes module 13.3 Every answer is explained when you check; a retake is always free. Source: RupeeCase Learn quiz rules (70% to pass). Passed ### Certificate ID Download PNGPrint or save as PDF[Check the ID](/learn/certificates/verify) Self paced and unproctored. A record of completing free education by RupeeCase; not a NISM certificate and not endorsed by NISM, NSE, BSE or SEBI. It qualifies no one to deal, advise or publish research. CCheck yourself ## Path 13 so far. Your quick check results on this device, stop by stop. Stop 3 of 7 on Path 13 Futures: every live stop, this module ringed. Source: RupeeCase Learn, Path 13. 1. [13.1Futures explained: long, short, leverage and daily mark to marketNot yet](/learn/path-13/module-13-1-futures-basics-mark-to-market) 2. [13.2Why futures trade above spot: basis, carry and convergenceNot yet](/learn/path-13/module-13-2-futures-basis-and-carry) 3. [13.3Open interest, volume and the four build up patternsNot yet](/learn/path-13/module-13-3-open-interest-and-build-ups#quiz) 4. [13.4Rollover: when, why and what it costsNot yet](/learn/path-13/module-13-4-futures-rollover) 5. [13.5Fair value of Nifty futures with dividendsNot yet](/learn/path-13/module-13-5-nifty-futures-fair-value) 6. [13.6Futures calendar spreads and roll yieldNot yet](/learn/path-13/module-13-6-futures-calendar-spreads) 7. [13.7Hedging with futures: beta, hedge ratio and lotsNot yet](/learn/path-13/module-13-7-hedging-with-futures) 8. [TPath test, 30 questionsNot yet](/learn/path-13/module-13-7-hedging-with-futures#pathTestSection) Explore next ## Put the module to work. * [Free module 15.1Reading the NSE option chain, column by column8 min read](/learn/path-15/module-15-1-reading-the-nse-option-chain) * [Free module 15.5Liquidity in the chain: spreads, volume and tradable strikes9 min read](/learn/path-15/module-15-5-option-chain-liquidity) * [ToolOption payoff builderLegs on a dated Nifty chain, breakevens and charges](/learn/tools/payoff-builder) Community ## Join my WhatsApp group. Scan the code, fillFill one short form, and join my WhatsApp group. Slides, sources, factsheets and the rebalance logs live there, and members join a daily Google Meet with me. New to RupeeCase? [Getting started](/getting-started) [See the terminal](/terminal) [Sign up for RupeeCase](https://invest.rupeecase.com/signup) [Join the WhatsApp group](https://forms.gle/C6HMtM1Z2GfeocQV7) [One form, one group](https://forms.gle/C6HMtM1Z2GfeocQV7)Scan with your phone camera SSources ## Go to the source. 6 sources, NSE the most cited The publisher of each source listed below. Source: Module 13.3 source list. 1. [NSE, derivatives end of day reports: F&O bhavcopy and participant wise open interest](https://www.nseindia.com/all-reports-derivatives) NSE 2. [NSE, equity derivatives contract specifications (futures cycle, expiry, tick size)](https://www.nseindia.com/static/products-services/equity-derivatives-contract-specifications) NSE 3. [NSE Indices, Nifty 50 Arbitrage index](https://niftyindices.com/indices/equity/strategy-indices/nifty-50-arbitrage) NSE 4. [SEBI Investor, Understanding derivatives](https://investor.sebi.gov.in/understanding_derivatives.html) SEBI 5. [NISM, Series VIII Equity Derivatives certification examination](https://www.nism.ac.in/revamp-nism/equity-derivatives/) NISM 6. Hull, J., Options, Futures, and Other Derivatives, Pearson Book GTerms ## 6 terms from this module. Open interestThe number of contracts still open at the close, counted once for each buyer and seller pair. [Volume](/learn/glossary#volume)The number of contracts traded during the day, whatever they did to open interest. Change in open interestOpen interest today minus open interest yesterday. It shows contracts opened or closed, not who did it. Long build upPrice up and open interest up. Read as new buyers, a description of the day and not a signal. Short coveringPrice up and open interest down. Read as sellers buying back to close. Long unwindingPrice down and open interest down. Read as buyers selling to close. [All 230 terms in the glossary](/learn/glossary) [Question people askWhat are open interest, change in OI and cumulative OI?A short answer with a dated chart](/learn/questions/what-is-open-interest)[Question people askLong build-up, short build-up, short covering, long unwinding?A short answer with a dated chart](/learn/questions/long-short-build-up)[Related module13.1 Futures explained: long, short, leverage and daily mark to market8 min, Beginner](/learn/path-13/module-13-1-futures-basics-mark-to-market)[Related module13.4 Rollover: when, why and what it costs8 min, Beginner](/learn/path-13/module-13-4-futures-rollover)[Pillar guideDerivatives and Quant115 modules across paths 12 to 19](/learn/derivatives) Education only, not investment advice, a research report or a recommendation to buy, sell or hold any security. RupeeCase (QC Alpha Technologies Pvt Ltd) is not registered with SEBI as an investment adviser or research analyst. Contracts and prices shown are for illustration only, come from NSE end of day files at least 30 days old, and are not recommendatory. Derivatives trading carries a high risk of loss.