# OI in Options Trading: How to Read OI Data, Change in OI and Analysis Author: AlgoTest Author URL: https://algotest.in/blog/author/algotest/ Published: 2026-08-22 Category: option chain Category URL: https://algotest.in/blog/category/option-chain/ Meta Title: OI in Options Trading: How to Read OI Data, Change in OI and Analysis Meta Description: Learn what OI means in options trading, how to read OI data and Change in OI, and how to compare Call vs Put OI using an option chain. Tags: options, options trading Tag URLs: options (https://algotest.in/blog/tag/options/), options trading (https://algotest.in/blog/tag/options-trading/) URL: https://algotest.in/blog/oi-in-options-trading/ When you open an [option chain](https://algotest.in/sensex-option-chain), the OI columns may contain some of the largest numbers on the screen. The difficult part is understanding what these numbers mean and whether they are useful for your trade. High OI does not automatically mean the market will rise or fall. To use it correctly, you need to compare OI with Change in OI, price, volume, and Call and Put activity. Let's see how OI works and how you can use it during [option chain analysis](https://algotest.in/blog/option-chain-analysis/). ## What Is OI in Options Trading? ![Oi Data](https://prod.superblogcdn.com/site_cuid_cmbhlz3q0002sxzc513a62pj5/images/chatgpt-image-aug-22-2026-011811-pm-1787385031236-compressed.png) OI stands for open interest. It shows the total number of futures or options contracts that remain open. These contracts have not been closed, exercised, or expired. Every contract has a buyer and a seller, but it is counted only once. OI does not tell you whether buyers or sellers are right. It only shows how many contracts are still active. ## How Does Open Interest Change? OI changes when traders create, transfer, or close positions. Consider this simple example. Trade What happens Change in OI Trader A buys and Trader B sells Both traders open a new position OI increases by one Trader A exits and Trader C enters The existing position moves to another trader OI does not change Trader C and Trader B close their positions The open contract is closed OI decreases by one This is why OI and trading activity are not the same. A contract may trade several times without creating the same increase in open interest. Learn more about [OI in our documentation](https://docs.algotest.in/financial-education/futures/open-interest/#open-interest-oi) ## What Does OI Data Show in an Option Chain? An [option chain](https://algotest.in/sensex-option-chain) shows OI separately for Calls and Puts. You can check this data for every strike and expiry. The main columns include. - OI, the number of contracts that are currently open. - Change in OI, the increase or decrease in open contracts during the period shown. - Volume, the number of contracts traded during the session. - LTP, the latest traded premium of the option. - Implied volatility, the expected volatility reflected in the premium. - Strike price, the price linked to the option contract. - Expiry, the date on which the contract expires. You do not need to study every column at once. Start with OI, Change in OI, volume, LTP, strike price, and expiry. You can learn more about volatility in the guide to [implied volatility and how to read IV](https://algotest.in/blog/implied-volatility-and-how-to-read-and-compute-iv/). ## OI vs Change in OI vs Volume OI, Change in OI, and volume answer different questions. Metric What it tells you OI How many contracts remain open Change in OI Whether open positions are increasing or decreasing Volume How many contracts traded during the session Volume normally resets at the start of each trading day. OI continues until positions close or the contract expires. Suppose an option records volume of 50,000 contracts but OI increases by only 5,000. This means trading activity was high, but only 5,000 additional contracts remained open. You can read the full comparison in the guide to [volume in an option chain](https://algotest.in/blog/how-to-read-volume-in-an-option-chain/). ## How to Read Price and OI Together You can compare price movement with OI movement to understand whether positions are building or being closed. This framework works most clearly with futures contracts. Price OI Possible reading Rising Rising Long build-up Falling Rising Short build-up Rising Falling Short covering Falling Falling Long unwinding Rising price with rising OI may show that fresh long positions are entering. Falling price with rising OI may show that fresh short positions are entering. Rising price with falling OI may indicate short covering. Falling price with falling OI may indicate that existing long positions are closing. Be careful when applying this framework to options. The underlying price and the option premium are different. Every option also has a buyer and a seller. OI alone cannot tell you who started the trade or whether the position is part of a hedge. Free Sign Up ## Call vs Put OI, What Is the Difference? Call vs Put OI compares open positions on both sides of the option chain. It helps you see where positions are concentrated around the current market price. You may see traders treat high Call OI as possible resistance. High Put OI is often treated as possible support. These levels are not guaranteed. OI cannot tell you whether the positions belong to buyers, sellers, spreads, or hedges. Treat high OI strikes as zones to watch. Then check how price and Change in OI behave around those zones. OI observation What it may mean What you should confirm High and rising Call OI near the current price Possible resistance or increased Call activity Underlying price, Call premium, volume, and Change in OI Falling Call OI Earlier Call positions may be closing Whether price can move above the strike High and rising Put OI near the current price Possible support or increased Put activity Underlying price, Put premium, volume, and Change in OI Falling Put OI Earlier Put positions may be closing Whether price holds or moves below the strike You can also use OI while [choosing the right strike price](https://algotest.in/blog/how-to-choose-the-right-strike-price/). However, you should also consider liquidity, implied volatility, premium, and the bid and ask spread. ## How Does Put Call Ratio Use OI? The Put Call Ratio, or PCR, compares Put activity with Call activity. An OI based PCR is calculated by dividing total Put OI by total Call OI for the selected expiry. PCR can help you understand the overall balance between Call and Put positioning. However, you should not use one PCR value as a direct buy or sell signal. You can read the complete formula and interpretation in the guide to [Put Call Ratio](https://algotest.in/blog/put-call-ratio-a-key-indicator-for-options-traders/). ## How Are OI and Max Pain Connected? Max pain is calculated using open interest across different strikes. It estimates the strike where option writers would have the lowest total payout at expiry. This does not mean the market must close at the max pain strike. Strong price moves, news, or changes in OI can make the earlier level less useful. Read more about the calculation and its limitations in the guide to [max pain in options trading](https://algotest.in/blog/max-pain-in-options-trading-what-it-means-and-how-it-works/). ## A Simple Call vs Put OI Example Suppose Sensex is trading near 82,100 for a selected expiry. The following figures are hypothetical and do not represent current market data. Contract Total OI Change in OI Initial observation 82,500 Call 5.2 lakh Positive 60,000 82,500 may be an important upper zone 81,500 Put 4.7 lakh Positive 40,000 81,500 may be an important lower zone This does not prove that Sensex will remain between 81,500 and 82,500. It only tells you where open positions are concentrated. Suppose Call OI at 82,500 begins to fall while Sensex moves above the strike with stronger volume. This may indicate that the upper zone is weakening. If Put OI at 81,500 falls while Sensex moves lower, the lower zone may also be losing importance. For a deeper index-specific explanation, read the guide to [Sensex OI data](https://algotest.in/blog/how-to-read-sensex-oi-data/). ## Where Can You Check Live OI Data? You can check OI and Change in OI on exchange option chains and options trading platforms. The [NSE OI data page](https://www.nseindia.com/market-data/oi-spurts) publishes open interest information for NSE derivatives. Always check the latest exchange data before using an OI level. For BSE Sensex options, you can use the [live Sensex Option Chain](https://algotest.in/sensex-option-chain) on AlgoTest. It lets you compare Call and Put OI across strikes and expiries. You can also check option premium, volume, implied volatility, and other option chain data in the same view. This makes it easier to compare OI with the other factors that affect your analysis. If you want a wider walkthrough, read [how to analyse the Sensex Option Chain](https://algotest.in/blog/how-to-read-and-analyse-sensex-option-chain/). For Nifty, use the detailed guide to [Nifty OI data](https://algotest.in/blog/how-to-read-nifty-oi-data/). ## Common Mistakes When Reading OI ### 1\. Treating high OI as guaranteed support or resistance High OI shows that many contracts are open at a strike. It does not guarantee that price will stop there. ### 2\. Ignoring Change in OI A strike may have high total OI even when traders are closing positions. Always check whether OI is increasing or falling. ### 3\. Assuming OI reveals buyers or sellers Every contract has a buyer and a seller. OI cannot tell you whether a large position is a directional trade, a spread, or a hedge. ### 4\. Comparing different expiries Each expiry has its own OI structure. Compare Calls and Puts from the same expiry. ### 5\. Looking only at OI OI is only one part of option chain analysis. Compare it with price, volume, premium movement, implied volatility, and liquidity. If you need to understand how the market premium is affected by volatility and time, read the guide to the [option premium calculator](https://algotest.in/blog/option-premium-calculator/). ## A Practical OI Checklist Before using OI in your analysis, check the following points. - Use the correct underlying and expiry. - Start with the ATM and nearby strikes. - Mark the highest Call OI and Put OI zones. - Track Change in OI instead of relying on one reading. - Compare OI with the underlying price. - Check the option premium and volume. - Review implied volatility and liquidity. - Treat support and resistance as changing zones. - Define your risk before entering a trade. ## Use OI as Context, Not a Standalone Signal ![Oi in Options Trading](https://prod.superblogcdn.com/site_cuid_cmbhlz3q0002sxzc513a62pj5/images/screenshot-2026-07-29-191158-1787386227848-compressed.png)Sensex Option Chain \| AlgoTest OI data helps you see where futures and options positions remain open. Change in OI helps you see whether that positioning is building or weakening. Call vs Put OI can help you identify strikes that deserve closer attention. It cannot predict where the market will move next. Use OI with price, volume, premium behaviour, volatility, and expiry context. If you trade Sensex options, you can use the [AlgoTest Sensex Option Chain](https://algotest.in/sensex-option-chain) to study live strike-wise data before evaluating a setup. Join Us _Options trading involves risk. This article is for educational purposes and does not provide investment advice._ ## FAQs Q: What is OI in options trading? A: OI, or open interest, is the total number of option contracts that remain open. These contracts have not been closed, exercised, or expired. Each contract is counted once, even though it has both a buyer and a seller. Q: What is OI data? A: OI data shows how many futures or options contracts are currently open. In an option chain, you can see OI separately for Calls and Puts at each strike and expiry. Q: What does Change in OI mean? A: Change in OI shows whether the number of open contracts has increased or decreased. A positive number means new open positions were added. A negative number means existing positions were reduced. Q: What is the difference between OI and volume? A: OI counts the contracts that remain open. Volume counts all contracts traded during a session. Volume normally resets each trading day, while OI continues until positions are closed or the contract expires. Q: How do you read Call vs Put OI? A: Select one expiry and start with the ATM and nearby strikes. Compare Call OI with Put OI. Then check Change in OI, the underlying price, option premium, and volume before treating a strike as possible support or resistance. Q: Does high Call OI always mean resistance? A: No. High Call OI only shows that many Call positions are open at that strike. These positions may include buyers, sellers, spreads, or hedges. Check price and Change in OI before treating the strike as resistance. Q: Can OI predict market direction? A: OI cannot predict market direction on its own. It can show where positions are concentrated and whether participation is increasing or decreasing. Use it with price, volume, volatility, and proper risk management. --- This blog is powered by Superblog. Visit https://superblog.ai to know more. ---