[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"post:oi-data-explained-how-to-read-open-interest":3},{"id":4,"slug":5,"title":6,"excerpt":7,"imageUrl":8,"tags":9,"createdAt":14,"updatedAt":14,"wordCount":15,"readingMinutes":16,"html":17,"toc":18,"related":54,"prev":55,"next":70},"3xmeGZNNPxBfEt7TVs4d","oi-data-explained-how-to-read-open-interest","OI Data Explained: How to Read Open Interest for NIFTY and SENSEX","OI data explained: what open interest is, where the numbers come from, and five ways to read it for NIFTY and SENSEX, from change in OI to PCR and futures.","https:\u002F\u002Ffirebasestorage.googleapis.com\u002Fv0\u002Fb\u002Fnarenkram-672cc.firebasestorage.app\u002Fo\u002Fblog-images%2F1791918508950-cover-oidata-oi-data.png?alt=media&token=672b7ebd-2271-48cb-8e4d-a5c6bbe66a4d",[10,11,12,13],"oidata","open interest","nifty","options trading","2026-10-13T19:05:24.834Z",1308,6,"\u003Cp>Every option chain in India has a column called OI. It is one of the most useful numbers on the screen, and one of the easiest to misread. I trade index options and built \u003Ca href=\"https:\u002F\u002Fwww.oidata.in\u002F\">OIData\u003C\u002Fa>, an open interest analysis app, so I spend a lot of time with these numbers. This post covers what OI data is, where it comes from, how it changes through the day, and the five ways I read it for NIFTY and SENSEX.\u003C\u002Fp>\n\u003Ch2 id=\"what-oi-data-is\">What OI data is\u003Ca class=\"heading-anchor\" href=\"#what-oi-data-is\" aria-hidden=\"true\" tabindex=\"-1\">#\u003C\u002Fa>\u003C\u002Fh2>\n\u003Cp>Open interest (OI) is the number of contracts that are still open: bought and sold, and not yet closed or expired. It is counted for every contract separately, so the 25,000 call expiring next Tuesday has its own OI, and the 25,000 put has another.\u003C\u002Fp>\n\u003Cp>Every contract has two sides, a buyer and a seller, so OI counts contracts, not bets. That is why the same number can rise or fall for different reasons:\u003C\u002Fp>\n\u003Cul>\n\u003Cli>\u003Cstrong>A new buyer trades with a new seller:\u003C\u002Fstrong> a new contract opens and OI goes up.\u003C\u002Fli>\n\u003Cli>\u003Cstrong>Someone hands their position to someone new:\u003C\u002Fstrong> the contract stays open with a different owner, and OI does not change.\u003C\u002Fli>\n\u003Cli>\u003Cstrong>A buyer and a seller who both held positions close them against each other:\u003C\u002Fstrong> a contract closes and OI goes down.\u003C\u002Fli>\n\u003C\u002Ful>\n\u003Cp>Volume is different. Volume counts every trade made today, however briefly the position was held; OI counts what is still open. A strike can trade heavily all day and end with almost no change in OI, because the same positions kept changing hands. OIData's blog has a longer piece on \u003Ca href=\"https:\u002F\u002Fwww.oidata.in\u002Fblog\u002Fopen-interest-vs-volume-whats-the-difference-and-why-it-matters\">open interest vs volume\u003C\u002Fa>.\u003C\u002Fp>\n\u003Cp>One small trap: some screens show OI in lots and others in quantity (lots multiplied by the lot size, which the exchange revises from time to time). Compare numbers in the same unit.\u003C\u002Fp>\n\u003Ch2 id=\"where-oi-data-comes-from\">Where OI data comes from\u003Ca class=\"heading-anchor\" href=\"#where-oi-data-comes-from\" aria-hidden=\"true\" tabindex=\"-1\">#\u003C\u002Fa>\u003C\u002Fh2>\n\u003Cp>The exchange counts open interest for every contract: NSE for NIFTY, BANK NIFTY and stock F&O, and BSE for SENSEX. It changes through the trading day as positions open and close, and every broker's option chain shows it. After the close, NSE also publishes participant-wise open interest: how the day's open positions are split between foreign investors (FIIs), domestic institutions (DIIs), proprietary traders and everyone else (clients).\u003C\u002Fp>\n\u003Cp>In OIData, the numbers come from the market data available through your own broker connection, refreshed roughly every 30 seconds during market hours, and OIData keeps a record of each session so you can go back over it later.\u003C\u002Fp>\n\u003Ch2 id=\"the-five-ways-i-read-oi-data\">The five ways I read OI data\u003Ca class=\"heading-anchor\" href=\"#the-five-ways-i-read-oi-data\" aria-hidden=\"true\" tabindex=\"-1\">#\u003C\u002Fa>\u003C\u002Fh2>\n\u003Ch3 id=\"1-oi-by-strike-where-the-positions-sit\">1. OI by strike: where the positions sit\u003Ca class=\"heading-anchor\" href=\"#1-oi-by-strike-where-the-positions-sit\" aria-hidden=\"true\" tabindex=\"-1\">#\u003C\u002Fa>\u003C\u002Fh3>\n\u003Cp>Lay call OI and put OI side by side for every strike and the heavy strikes stand out. Option sellers usually hold the biggest positions, so traders read these levels from the sellers' side: the strike with the most call OI is often read as resistance, because call sellers lose if the price climbs past it, and the strike with the most put OI as support, for the same reason on the way down.\u003C\u002Fp>\n\u003Cp>These are levels people are defending, not promises. In OIData, \u003Ca href=\"https:\u002F\u002Fwww.oidata.in\u002Foi-stats\">OI Stats\u003C\u002Fa> draws the whole ladder as bars, so the walls are obvious without reading digits.\u003C\u002Fp>\n\u003Ch3 id=\"2-change-in-oi-what-is-being-built-today\">2. Change in OI: what is being built today\u003Ca class=\"heading-anchor\" href=\"#2-change-in-oi-what-is-being-built-today\" aria-hidden=\"true\" tabindex=\"-1\">#\u003C\u002Fa>\u003C\u002Fh3>\n\u003Cp>The total OI at a strike piles up over the whole life of a contract. The change since today's open is what tells you about today. Say the price is near 25,000 and the 25,100 call holds a large OI, but its OI has fallen sharply since the open. The wall is still the biggest on the screen, but the sellers holding it are leaving, which is the opposite of what the total suggests.\u003C\u002Fp>\n\u003Cp>That is why I read the change column before the total, and why OIData's \u003Ca href=\"https:\u002F\u002Fwww.oidata.in\u002Foption-chain\">option chain\u003C\u002Fa> puts the change and its percentage beside every OI figure. More on this in OIData's post on \u003Ca href=\"https:\u002F\u002Fwww.oidata.in\u002Fblog\u002Fchange-in-oi-explained-which-strikes-are-adding-open-interest\">change in OI\u003C\u002Fa>.\u003C\u002Fp>\n\u003Ch3 id=\"3-oi-with-price-the-four-build-ups\">3. OI with price: the four build-ups\u003Ca class=\"heading-anchor\" href=\"#3-oi-with-price-the-four-build-ups\" aria-hidden=\"true\" tabindex=\"-1\">#\u003C\u002Fa>\u003C\u002Fh3>\n\u003Cp>OI alone has no direction. Paired with the price, it does:\u003C\u002Fp>\n\u003Cul>\n\u003Cli>\u003Cstrong>OI up, price up:\u003C\u002Fstrong> long build-up. New buyers are paying up.\u003C\u002Fli>\n\u003Cli>\u003Cstrong>OI up, price down:\u003C\u002Fstrong> short build-up. New sellers are pressing.\u003C\u002Fli>\n\u003Cli>\u003Cstrong>OI down, price up:\u003C\u002Fstrong> short covering. Sellers are buying back.\u003C\u002Fli>\n\u003Cli>\u003Cstrong>OI down, price down:\u003C\u002Fstrong> long unwinding. Buyers are getting out.\u003C\u002Fli>\n\u003C\u002Ful>\n\u003Cp>For an option, "price" means its premium. The same four readings apply to futures, where they are cleaner, because a futures position has no strike and no seller's view of a level to untangle. OIData's post on \u003Ca href=\"https:\u002F\u002Fwww.oidata.in\u002Fblog\u002Foi-buildup-explained-long-buildup-short-buildup-short-covering-long-unwinding\">the four build-ups\u003C\u002Fa> has worked examples.\u003C\u002Fp>\n\u003Ch3 id=\"4-the-put-call-ratio\">4. The put-call ratio\u003Ca class=\"heading-anchor\" href=\"#4-the-put-call-ratio\" aria-hidden=\"true\" tabindex=\"-1\">#\u003C\u002Fa>\u003C\u002Fh3>\n\u003Cp>The put-call ratio (PCR) is the total put OI divided by the total call OI. Read from the sellers' side again, a PCR above 1 means more puts than calls are open, which traders usually read as sellers expecting a floor, and below 1 as the opposite. OIData's option chain reads PCR above 1 as bullish and below 1 as bearish.\u003C\u002Fp>\n\u003Cp>PCR is a summary, and summaries hide things. A very high PCR can mean a crowded market as much as a confident one, and one far-away strike can move it a lot. Watch which way it is heading through the day rather than one value. OIData's blog explains \u003Ca href=\"https:\u002F\u002Fwww.oidata.in\u002Fblog\u002Fput-call-ratio-pcr-explained-how-to-read-it-without-getting-fooled\">how to read PCR without getting fooled\u003C\u002Fa>.\u003C\u002Fp>\n\u003Ch3 id=\"5-futures-oi-and-who-holds-it\">5. Futures OI, and who holds it\u003Ca class=\"heading-anchor\" href=\"#5-futures-oi-and-who-holds-it\" aria-hidden=\"true\" tabindex=\"-1\">#\u003C\u002Fa>\u003C\u002Fh3>\n\u003Cp>Index futures show direction more plainly than options, and NSE's daily participant figures tell you who is on which side: whether foreign investors are net long or net short index futures, for example, and how that changed from yesterday. OIData's \u003Ca href=\"https:\u002F\u002Fwww.oidata.in\u002Ffutures-oi\">Futures OI\u003C\u002Fa> and \u003Ca href=\"https:\u002F\u002Fwww.oidata.in\u002Fparticipants\">FII \u002F DII Activity\u003C\u002Fa> pages cover both, and its blog explains \u003Ca href=\"https:\u002F\u002Fwww.oidata.in\u002Fblog\u002Fparticipant-wise-open-interest-nse\">participant-wise open interest\u003C\u002Fa>.\u003C\u002Fp>\n\u003Ch2 id=\"when-oi-data-moves-the-most\">When OI data moves the most\u003Ca class=\"heading-anchor\" href=\"#when-oi-data-moves-the-most\" aria-hidden=\"true\" tabindex=\"-1\">#\u003C\u002Fa>\u003C\u002Fh2>\n\u003Cp>OI often moves most in the morning, as the day's new positions go on, and around expiry. NIFTY's weekly options expire on Tuesdays and SENSEX's on Thursdays, and NIFTY's monthly contract on the last Tuesday of the month; when an expiry day is a market holiday, the expiry moves to the previous trading day. On expiry day OI falls quickly as contracts are closed, so a falling OI that day means something different from a falling OI on a Wednesday.\u003C\u002Fp>\n\u003Ch2 id=\"five-mistakes-with-oi-data\">Five mistakes with OI data\u003Ca class=\"heading-anchor\" href=\"#five-mistakes-with-oi-data\" aria-hidden=\"true\" tabindex=\"-1\">#\u003C\u002Fa>\u003C\u002Fh2>\n\u003Col>\n\u003Cli>\u003Cstrong>Reading OI as direction.\u003C\u002Fstrong> Every contract has a buyer and a seller. OI says where positions are, not who will win.\u003C\u002Fli>\n\u003Cli>\u003Cstrong>Looking at totals and ignoring the change.\u003C\u002Fstrong> The total is history; the change is today.\u003C\u002Fli>\n\u003Cli>\u003Cstrong>Mixing expiries.\u003C\u002Fstrong> The 25,000 call of this week and of next month are different contracts with different OI. Make sure you are reading the expiry you trade.\u003C\u002Fli>\n\u003Cli>\u003Cstrong>Trusting one snapshot.\u003C\u002Fstrong> The levels move during the day. Check how a strike got there, not only where it stands. OIData's \u003Ca href=\"https:\u002F\u002Fwww.oidata.in\u002Fchart\">Session Chart\u003C\u002Fa> and \u003Ca href=\"https:\u002F\u002Fwww.oidata.in\u002Fstrike-history\">Strike History\u003C\u002Fa> exist for exactly this.\u003C\u002Fli>\n\u003Cli>\u003Cstrong>Treating a level as a promise.\u003C\u002Fstrong> A heavy strike is defended until it is not. Read OI alongside price, never instead of it.\u003C\u002Fli>\n\u003C\u002Fol>\n\u003Ch2 id=\"where-to-read-oi-data\">Where to read OI data\u003Ca class=\"heading-anchor\" href=\"#where-to-read-oi-data\" aria-hidden=\"true\" tabindex=\"-1\">#\u003C\u002Fa>\u003C\u002Fh2>\n\u003Cp>Your broker's option chain shows OI and its change, and NSE and BSE show option chains on their own websites. That is enough to start. An analysis tool earns its place when it adds what those screens leave out: the session's history, the change across strikes as a chart, the build-ups labelled for you, futures and participant data in the same place, and alerts.\u003C\u002Fp>\n\u003Cp>That is what I built OIData to do, for NIFTY, BANK NIFTY, SENSEX and every F&O stock. It shows information for your own research and never tells you to buy or sell; it is not a SEBI-registered investment adviser. There is one plan, Ultimate, at ₹1189 a month or ₹10,701 a year. I also wrote about \u003Ca href=\"https:\u002F\u002Fwww.narenkram.com\u002Fblog\u002Fwhat-to-look-for-in-an-open-interest-analysis-tool\">what to look for in an open interest analysis tool\u003C\u002Fa>, whichever one you end up using.\u003C\u002Fp>\n\u003Cp>If you are just starting, OIData's posts on \u003Ca href=\"https:\u002F\u002Fwww.oidata.in\u002Fblog\u002Fwhat-is-open-interest\">what open interest is\u003C\u002Fa> and \u003Ca href=\"https:\u002F\u002Fwww.oidata.in\u002Fblog\u002Fhow-to-read-the-nifty-bank-nifty-option-chain\">how to read the option chain\u003C\u002Fa> are good next steps.\u003C\u002Fp>\n",[19,23,26,29,33,36,39,42,45,48,51],{"id":20,"text":21,"level":22},"what-oi-data-is","What OI data is",2,{"id":24,"text":25,"level":22},"where-oi-data-comes-from","Where OI data comes from",{"id":27,"text":28,"level":22},"the-five-ways-i-read-oi-data","The five ways I read OI data",{"id":30,"text":31,"level":32},"1-oi-by-strike-where-the-positions-sit","1. OI by strike: where the positions sit",3,{"id":34,"text":35,"level":32},"2-change-in-oi-what-is-being-built-today","2. Change in OI: what is being built today",{"id":37,"text":38,"level":32},"3-oi-with-price-the-four-build-ups","3. OI with price: the four build-ups",{"id":40,"text":41,"level":32},"4-the-put-call-ratio","4. The put-call ratio",{"id":43,"text":44,"level":32},"5-futures-oi-and-who-holds-it","5. Futures OI, and who holds it",{"id":46,"text":47,"level":22},"when-oi-data-moves-the-most","When OI data moves the most",{"id":49,"text":50,"level":22},"five-mistakes-with-oi-data","Five mistakes with OI data",{"id":52,"text":53,"level":22},"where-to-read-oi-data","Where to read OI data",[],{"id":56,"slug":57,"title":58,"excerpt":59,"imageUrl":60,"tags":61,"createdAt":66,"updatedAt":67,"wordCount":68,"readingMinutes":69},"MPA3neju03I2YggNl29r","interactive-product-demo-examples","Interactive Product Demo Examples I Built for My Own Apps","Interactive product demo examples I made for my own apps, OIData and ShotDemo: how each was built, what every step says, and what to copy for your own demo.","https:\u002F\u002Ffirebasestorage.googleapis.com\u002Fv0\u002Fb\u002Fnarenkram-672cc.firebasestorage.app\u002Fo\u002Fblog-images%2F1791918510371-cover-shotdemo-examples.png?alt=media&token=0e42a4e9-8131-4193-9e05-1e7ab85ea976",[62,63,64,65],"shotdemo","interactive demo","product demo","saas","2026-10-13T19:04:24.834Z","2026-10-28T08:45:49.597Z",1447,7,{"id":71,"slug":72,"title":73,"excerpt":74,"imageUrl":75,"tags":76,"createdAt":77,"updatedAt":77,"wordCount":78,"readingMinutes":16},"A4T7XyNjhY7uRewPqmbW","what-to-look-for-in-an-open-interest-analysis-tool","What to Look For in an Open Interest Analysis Tool","What to look for in an open interest analysis tool for NIFTY and SENSEX, from the person who built OIData: change in OI, build-ups, history, alerts and price.","https:\u002F\u002Ffirebasestorage.googleapis.com\u002Fv0\u002Fb\u002Fnarenkram-672cc.firebasestorage.app\u002Fo\u002Fblog-images%2F1791918508067-cover-oidata-tool.png?alt=media&token=9015f83c-a39f-4007-badd-68dc7bf4b05b",[10,11,13,65],"2026-10-13T19:06:24.834Z",1325]