Options Chain Analysis: Reading the OI Ladder

Anatomy of the Options Chain: Every Column Explained

The options chain on NSE's market data feed - or as displayed through any broker terminal - is organised around a central spine of strike prices. To the left of this spine sit the call option columns; to the right sit the put option columns. Understanding what each column represents is the essential first step.

Strike Price (ATM Highlighted) The strike price column runs vertically down the centre. For Nifty 50, strikes are typically spaced 50 points apart, though weekly expiries sometimes offer tighter spacing near the at-the-money (ATM) level. The ATM strike - the one closest to the current spot price - is usually highlighted in a different colour. Strikes above the current spot are called out-of-the-money (OTM) for calls and in-the-money (ITM) for puts. Strikes below the spot are ITM for calls and OTM for puts.

Last Traded Price (LTP) This is simply the last price at which a transaction occurred for that particular call or put. LTP changes continuously during market hours (9:15 AM to 3:30 PM IST on NSE). For very deep ITM or very deep OTM strikes, LTP may not change for minutes at a time because liquidity is thin.

Bid and Ask (Bid-Ask Spread) The bid price is what buyers are willing to pay; the ask price is what sellers want. The difference is the bid-ask spread, and it is a direct measure of liquidity. For ATM and near-ATM Nifty strikes, the spread is typically just one rupee or even 50 paise on a liquid contract. For far OTM strikes, the spread can be ₹5 to ₹20 or more, meaning you immediately lose value just by entering the trade.

Open Interest (OI) Open interest is the total number of outstanding contracts that have not yet been settled or squared off. Each contract represents a lot - for Nifty 50, one lot is 25 units. A high OI at a particular strike indicates a large number of participants have positions there. OI is cumulative - it builds over the life of the contract and only falls when positions are closed or exercised.

Change in OI This column shows how much OI has increased or decreased compared to the previous trading session (or from the beginning of the current session, depending on the platform). Rising OI alongside rising price suggests new long positions being built. Rising OI alongside falling price suggests new short positions. These combinations are the basis of the "OI interpretation" framework we will explore in detail.

Volume Volume is the number of contracts traded during the current session. Unlike OI, volume resets to zero at the start of each trading day. High volume at a strike confirms active interest; low volume suggests thin participation and potentially unreliable pricing.

Implied Volatility (IV) IV is the market's collective expectation of future volatility for the underlying, extracted from the option's current market price. A high IV means options are expensive; a low IV means they are cheap - relative to historical norms. Each strike can have a slightly different IV, and plotting these creates the IV skew curve, which we discuss separately.

ITM, ATM, OTM Classification Most modern platforms colour-code or shade the ITM strikes to make the chain easier to read at a glance. Understanding this shading immediately tells you where intrinsic value exists and where the premium is entirely time value and volatility expectation.

Taken together, these columns transform from isolated numbers into a rich map of market sentiment. Learning to read them in combination - not column by column in isolation - is the core skill of options chain analysis.

What Is the OI Ladder and Why Does It Matter?

The term "OI ladder" refers to the ranked or stacked view of open interest across all strike prices for a given expiry. Imagine taking the OI column from an options chain, sorting it visually by strike, and drawing horizontal bars proportional to the OI at each strike - you would get a bar chart that looks like rungs on a ladder. This visual makes it immediately clear where the heaviest concentration of open positions sits.

Why does the OI ladder matter? Because open interest represents real money committed by real market participants. Option writers - who are typically well-capitalised institutional entities, proprietary trading desks, or sophisticated retail traders - often defend the strikes at which they have written large quantities of options. A strike with enormous call open interest effectively acts as a ceiling in many traders' mental models, because the writers of those calls have an incentive to keep the price below that level to avoid paying out on their short positions. Similarly, a strike with enormous put open interest can act as a floor.

This logic underpins the concept of "support and resistance through OI", which is one of the most widely discussed ideas in the Indian options trading community. Let us be clear about something important: OI concentration does not guarantee price will stop at a level. Markets can and do blow through heavily written strikes, especially during sharp news events, index rebalancing, or F&O expiry dynamics. The OI ladder is a probabilistic guide, not a wall.

How to Read the OI Ladder Practically On any given trading day for a Nifty 50 monthly expiry, you might see the following scenario: the 50-call OI at a strike 200 points above spot is 80 lakh contracts, while the put OI at a strike 200 points below spot is 65 lakh contracts. In trader parlance, there is a "call wall" above and a "put wall" below, suggesting the market may consolidate between these two levels unless a catalyst drives a breakout.

The OI ladder becomes particularly useful during expiry week. As contracts approach settlement, OI shifts rapidly as participants close, roll, or adjust their positions. Monitoring how the call wall and put wall migrate - do they stay fixed? Do they move higher as the market rallies? - gives you a real-time picture of how market makers and option writers are repositioning.

Distinguishing Fresh OI from Rollovers Not all OI is equal. Near expiry, a large chunk of OI may represent rollovers - traders closing a near-month position and reopening the same position in the next expiry. Fresh OI, by contrast, reflects genuine new bets on the current expiry. Most platforms display total OI, so you have to use your judgement and cross-reference with change-in-OI and volume data to estimate how much is fresh versus rolled.

Strike-Wise OI and the 52-Week Perspective Some advanced platforms allow you to compare current OI at a strike with its historical range over the past year. A strike currently holding its highest-ever OI is a more significant level than one holding average OI. This historical context adds meaningful depth to your OI ladder reading.

In the Indian market, where F&O participation has grown dramatically - NSE's daily F&O turnover regularly exceeds several crore lots - the OI ladder has become one of the most-watched tools by both retail participants and institutional desks. Understanding it is no longer optional for anyone serious about trading index or stock options.

Open Interest Interpretation: The Four Classic Combinations

Traders have long used the relationship between price movement and change in open interest to infer whether the market is accumulating fresh directional positions or whether existing positions are being unwound. There are four classic combinations, each carrying a distinct implication.

Combination 1: Price Rising + OI Rising - Long Build-Up When the underlying price moves up and open interest also increases, it typically indicates that new long positions are being added to the market. Buyers are entering fresh, and sellers are willing to create new supply at higher prices. This is generally considered a bullish signal, suggesting the upward trend has conviction behind it. In an options context, rising call OI at above-market strikes alongside rising spot might indicate call option buyers are positioning for further upside.

Combination 2: Price Rising + OI Falling - Short Covering When price rises but OI falls, it suggests the rally is being driven by short sellers covering their existing positions rather than by fresh buyers entering the market. Short covering rallies can be sharp but tend to be less sustained than long build-up rallies, because once the shorts have covered, the buying pressure dissipates. Traders often watch this combination with some caution - the rally may stall once the covering is complete.

Combination 3: Price Falling + OI Rising - Short Build-Up Falling price alongside rising OI is the bearish mirror of Combination 1. It suggests that new short positions are being added at lower prices - sellers are aggressive and buyers are being absorbed. This is generally interpreted as bearish confirmation, indicating that the downward move has institutional or at least broad-based participation. Watching for rising put OI at below-market strikes in tandem with falling spot can help confirm a bearish short build-up in options.

Combination 4: Price Falling + OI Falling - Long Unwinding This combination suggests that existing long positions are being liquidated. The market is falling not because bears are aggressively shorting, but because bulls are exiting. Long unwinding can be a precursor to a trend reversal if the selling pressure exhausts itself, or it can accelerate a decline if the exits become panicked. On the OI ladder, you would see large reductions in OI at strikes that previously had heavy call OI - these longs are getting out.

Applying These Combinations to the Options Chain In practice, you apply this framework to both the futures OI for the underlying (where available) and to the specific option strikes. For instance, if the Nifty spot is at 23,000 and you observe that the 23,200 call OI has risen by 50 lakh contracts while price has moved up, you have a long build-up in calls. Simultaneously, if the 22,800 put OI is also rising, it suggests put writers are selling puts - another bullish signal, as put writers typically do so when they believe the downside is limited.

It is worth emphasising that no single OI reading is definitive. These combinations work better on a weight-of-evidence basis - when multiple strikes, multiple days, and multiple data points all point in the same direction. A single session's OI change can be misleading, especially near expiry or around significant events like RBI monetary policy announcements, Union Budget, or quarterly earnings seasons.

The Role of F&O Ban Stocks For individual stock options, SEBI and the exchanges impose an F&O ban when total OI in a stock's futures and options exceeds 95% of the market-wide position limit (MWPL). During a ban period, no fresh positions can be taken - only existing positions can be closed. This dramatically affects OI dynamics. A stock under F&O ban will show falling OI almost mechanically, which can confuse the standard four-combination framework. Always check whether a stock is under F&O ban before interpreting its OI changes.

Implied Volatility Skew: Reading the Shape of the Chain

Every strike in the options chain carries its own implied volatility (IV). If you plot these IVs against their respective strikes, you get the volatility skew curve - and its shape tells you a great deal about market sentiment and where participants perceive the greatest risk.

The Volatility Smile and Smirk In a theoretical world, IV would be flat across all strikes - but markets are not theoretical. In equity index markets like Nifty 50, IV typically rises as you move to lower strikes (puts become progressively more expensive) and is somewhat lower at higher strikes (calls are relatively cheaper). This asymmetry is called a volatility skew or, colloquially, a "smirk" - it tilts upward on the put side. The reason is structural: fund managers, institutional investors, and hedgers consistently buy OTM puts to protect their long equity portfolios against sharp downside moves. This persistent demand for downside protection bids up put IVs.

In commodity markets on MCX - crude oil, gold, silver - the skew can look quite different, sometimes resembling a true smile (both wings elevated) when there is genuine two-sided uncertainty about price direction.

ATM IV as the Market's Barometer The IV of the ATM option is the most widely quoted volatility figure for any underlying. For Nifty 50, the India VIX - published by NSE - is essentially a 30-day ATM IV measure, calculated using a methodology adapted from the CBOE VIX. When India VIX is elevated (say, above 20), option premiums are expensive across the board. When it is low (say, below 12), options are cheap. Traders often compare India VIX levels against historical ranges to assess whether buying or selling options offers a structural edge at current pricing.

Term Structure: Near vs. Far Expiry IV Options chains are available for multiple expiries simultaneously - weekly, monthly, and quarterly for index contracts. Plotting ATM IV across these expiries gives you the volatility term structure. In normal conditions, near-expiry IV is lower than far-expiry IV (upward-sloping term structure), reflecting greater uncertainty over a longer horizon. However, before a known event - like the Union Budget, RBI policy, or a general election result - near-expiry IV can spike above far-expiry IV, creating an inverted term structure. This inversion is a direct signal that the market is pricing a large near-term move.

IV Percentile and IV Rank Rather than looking at IV in isolation, experienced traders use IV Percentile (the percentage of days in the past year where IV was lower than today) and IV Rank (where today's IV sits within the past year's range). A Nifty option with an IV of 16% may seem low, but if IV has spent 90% of the past year below 16%, it is actually elevated. IV Rank and Percentile normalise the reading. Many Indian broker terminals now display these figures directly on the options chain interface.

Skew as a Sentiment Gauge When put skew steepens - OTM puts become disproportionately more expensive relative to OTM calls - it signals rising fear and demand for downside protection. Conversely, when call skew rises (OTM calls more expensive than OTM puts), it can signal bullish sentiment or even speculative call buying. During the 2020 market recovery and the 2021 bull run, the Nifty options chain periodically showed elevated call skew as retail participants piled into OTM call options, creating what traders called a "reverse skew" or "positive skew" phase.

Reading the skew alongside the OI ladder - rather than in isolation - gives a more complete picture. Heavy OI at a particular strike combined with elevated IV at that strike confirms that the market has strong convictions (and is paying for them) at that level.

Put-Call Ratio: Interpreting PCR from the Chain

The Put-Call Ratio (PCR) is one of the simplest and most widely referenced sentiment indicators derived from the options chain. It can be calculated in two ways: using open interest (PCR-OI) or using volume (PCR-Volume). The OI-based PCR is generally considered more meaningful for positional traders; the volume-based PCR is useful for short-term, intraday participants.

How PCR Is Calculated PCR-OI = Total Put Open Interest / Total Call Open Interest

If the total put OI across all Nifty strikes for the current expiry is 2.5 crore contracts and the total call OI is 2.0 crore contracts, the PCR-OI is 2.5 / 2.0 = 1.25.

Interpreting the PCR A PCR below 1 means more call OI than put OI, suggesting relatively more bullish bets (or, from a contrarian perspective, complacency). A PCR above 1 means more put OI, suggesting more bearish bets (or, from a contrarian perspective, excessive fear which could precede a bounce).

Here is the important nuance: PCR is typically used as a contrarian indicator. A very high PCR (say, above 1.5) suggests so much put-buying or put-selling that sentiment has become one-sided to the bearish side - which historically has often preceded market recoveries. A very low PCR (below 0.7) suggests one-sided bullishness, which has sometimes preceded corrections.

However, PCR interpretation must be contextualised. A high PCR can reflect either excessive fear (a contrarian buy signal) or genuine defensive hedging by institutional players (a legitimate bearish signal). The difference lies in whether the puts are being bought (defensive hedging) or sold (income generation by traders bullish on the market). You would need to cross-reference change-in-OI and volume data to distinguish these cases.

PCR Across Strike Ranges Many experienced traders do not look at aggregate PCR but instead slice it by strike range. For example, they might calculate PCR only for strikes within 3% of the current spot price (the "near-money" PCR) versus the broader market PCR. Near-money PCR tends to be a more refined sentiment gauge because it excludes very deep OTM options that are often purchased for highly speculative or tail-risk hedging purposes.

PCR and the Nifty 50 For Nifty 50, NSE publishes daily PCR data on its website as part of its F&O market statistics. Historical PCR data is freely available and can be used to establish ranges - the average Nifty PCR, its standard deviation, and its behaviour around key market events. Traders often plot a rolling 5-day average PCR alongside the Nifty spot price to identify divergences that may signal a sentiment shift.

The PCR-Volume Signal On an intraday basis, a sharp spike in put buying volume (relative to call buying volume) mid-session can signal institutional hedging or panic buying, which sometimes precedes short-covering rallies. Conversely, a sudden surge in call buying volume can suggest breakout participation, which, if not backed by underlying price movement, may indicate frothy speculation. Watching PCR-Volume alongside real-time price action is a technique used by many active intraday traders in Indian markets.

Change-in-OI Signals: Reading Fresh Positions and Unwinding

While the absolute OI level at a strike tells you about cumulative positions, the change in OI - particularly intraday change-in-OI displayed as a colour-coded addition to the chain - is often more actionable. It tells you what is happening right now, not just what has accumulated over weeks.

Intraday OI Build-Up in Calls When you observe, during the trading session, that call OI at a strike significantly above the current spot is rising rapidly alongside rising prices, it can mean one of two things: bullish call buyers are adding positions expecting further upside, or call writers who were previously short calls are closing (short-covering), and new writers are stepping in. The distinction matters because one is bullish speculation and the other is repositioning by premium sellers. Volume patterns - whether the transactions are at the bid or ask - can help distinguish these, though this level of granularity requires Level 2 market data.

Intraday OI Build-Up in Puts Similarly, rising put OI at a strike below spot during the session can indicate either bearish speculation (put buyers adding positions) or hedging activity by institutional long holders buying insurance. If the broader market is declining simultaneously, rising put OI confirms short build-up. If the market is rising but put OI is building, it might reflect institutional hedging - smart money going up but protecting the downside.

The Importance of the 1-Day Change vs. 5-Day Change Some traders prefer to look at the 5-day cumulative change in OI rather than just one-day change, arguing it filters out daily noise. A strike where OI has been steadily building over five consecutive sessions is a more reliable signal than one where OI jumped in a single day (which might be a block trade or a single large participant moving in).

OI Unwinding as a Reversal Signal Rapid OI unwinding - when large OI at a call or put strike collapses significantly - can signal an impending reversal. If the Nifty is at 22,800 and the 23,000 call OI suddenly drops by 40 lakh contracts in a single session while price is also rising, it suggests the call writers are covering their shorts. This "call wall" is being dismantled, and the overhead resistance is weakening. Traders interpret this as a potential breakout signal and watch for confirmation in price action and volume.

Shift in Max Pain Due to OI Changes Because max pain is a function of OI distribution, large intraday OI shifts can cause the max pain level to migrate. Some platforms update max pain calculations in real time, and watching this migration on expiry day can give a rough sense of where market makers are repositioning. A max pain level that moves steadily higher throughout the expiry day suggests writers are gradually repositioning for a higher settlement.

Data Refresh and Interpretation Delays In India, NSE provides OI data with a short delay on its public feeds, though most broker terminals refresh every 1-3 minutes using their own data pipes. For high-frequency intraday decisions, even a 1-minute delay can be material. Traders need to be aware of the data latency in their specific platform and not assume they are working with true real-time OI.

Sector and Index Options Together For a complete picture, experienced traders sometimes look at OI changes not just in Nifty 50 options but also in Bank Nifty, Nifty Financial Services, or sectoral options (where available) simultaneously. A uniform OI build-up across indices in one direction can confirm a broader market view; divergent signals between indices might indicate sector rotation rather than a broad directional move.

Using the Options Chain for Expiry-Day Analysis

Expiry day - every Thursday for weekly Nifty and Bank Nifty contracts, and the last Thursday of each month for monthly contracts - creates a unique environment in the options chain. Time decay (theta) accelerates dramatically. OI shifts can be violent. And the interplay between the spot market, futures, and options reaches its most complex and compressed form.

Theta Explosion in the Final Hour Options lose time value every day, but on expiry day - particularly in the last two hours of trading - theta decay becomes extreme for near-ATM options. An option that was priced at ₹50 at 9:30 AM may be worth less than ₹10 by 2:00 PM if the underlying has not moved significantly. This time-decay dynamic makes expiry-day trading very different from positional options trading. The OI ladder on expiry morning often shows sharp reductions in OI across the board as traders who opened positions earlier in the week close them before they expire worthless or with minimal value.

The "Pinning" Effect Some traders and researchers have documented an expiry-day "pinning" effect in Indian index options, where the Nifty or Bank Nifty tends to oscillate near the max pain level in the final session. The mechanical reason is that option writers who are delta-hedging their short options positions execute offsetting trades in the futures or cash market that push and pull the index toward the level where their hedges are neutral - which often coincides with the max pain point. This pinning is not guaranteed and can break sharply if a major event occurs, but it is a statistical tendency worth monitoring.

Short Gamma Risk on Expiry Day For option buyers on expiry day, the risk is straightforward: pay a small premium, and if the option does not go ITM, lose it entirely. For option sellers, however, expiry day carries "short gamma" risk - sudden large moves in the underlying can cause deep OTM options to swing rapidly into the money, creating catastrophic losses for writers who had assumed those strikes were safe. The Nifty's intraday swings of 100-200 points within minutes are not unusual on high-volatility days, and near-ATM options can reprice by ₹30-₹80 within minutes. Risk management is paramount.

Reading the Chain in the Last 30 Minutes Experienced expiry-day traders monitor the options chain very closely in the final 30 minutes. Patterns to watch: Which strikes have remaining OI above a threshold? Are call or put writers in danger of ITM settlement? Is there a large gamma squeeze potential? The bid-ask spreads on near-ATM options often widen in this period as market makers become more cautious. Volume surges at specific strikes in the final 30 minutes can sometimes indicate the direction of the final settlement move.

Post-Expiry Rollover and Chain Transition As soon as the Thursday expiry concludes, NSE automatically lists new weekly contracts for the following Thursday. Traders begin analysing the new chain immediately after the old expiry settles. The opening OI on the new contract - determined by rollovers and fresh positions opened after Thursday's close - forms the initial OI ladder for the new expiry week. Watching where the initial OI concentrations form on the new chain provides early clues about where the market consensus sees support and resistance in the coming week.

Options Chain for Different Underlyings: Index vs. Stock vs. Commodity

While the principles of options chain analysis remain consistent across underlyings, there are meaningful practical differences when reading the chain for index options (Nifty 50, Bank Nifty), individual stock options, and commodity options on MCX.

Index Options: High Liquidity, European Settlement Nifty 50 and Bank Nifty options are the most liquid options in India by a significant margin. Their chains typically show tight bid-ask spreads, high OI across dozens of strikes, and meaningful volume at both near and far strikes. These options are European-style - they can only be exercised at expiry, not before. This eliminates early exercise risk and means that American-style option pricing adjustments are not needed. The OI ladder for Nifty is usually the most reliable for the kind of support-resistance analysis described in earlier sections, simply because liquidity ensures that prices are efficient.

Stock Options: Illiquidity and Event Risk Individual stock options on NSE - currently listed on a selected group of large-cap and mid-cap stocks - often suffer from poor liquidity away from the near-ATM strikes. For a stock option, you might find meaningful OI and tight spreads only at 3-4 strikes near the current price, while everything else has sporadic trading and wide spreads. Event risk compounds this: corporate earnings, mergers, regulatory actions, or sector-specific news can cause sharp price moves that render the OI ladder irrelevant overnight. Traders analysing stock options chains must factor in upcoming events (results, AGMs, SEBI orders) very carefully.

Additionally, stock options in India are American-style (exercisable any time before expiry), which adds a theoretical early exercise component for deep ITM options. In practice, early exercise is rare because the time value typically makes selling the option preferable to exercising, but it is a consideration traders should understand.

Commodity Options on MCX MCX offers options on gold, silver, and crude oil, among others. The chains for these commodities look structurally similar to equity options chains, but the underlying dynamics are different. Commodity prices are influenced by global supply-demand, currency movements (most commodities are priced in USD internationally but traded in INR on MCX), geopolitical events, and seasonal factors. The IV skew for commodity options can look very different - crude oil options often show a significant upside skew (OTM calls are expensive relative to OTM puts) when supply shock risks dominate the narrative.

Commodity options on MCX are physically settled via the futures contract, not by cash, for most contracts. This settlement mechanism can affect OI behaviour near expiry differently from cash-settled index options.

NCDEX Agricultural Options National Commodity & Derivatives Exchange (NCDEX) lists options on agricultural commodities such as soybean and chana. These chains tend to have much lower liquidity than MCX metal and energy options. Analysing OI and volume data here requires even more caution given the thinness of the market.

Cross-Market Signals Sometimes, the most interesting signals come from comparing the options chains of related underlyings. For instance, comparing Bank Nifty option IV with Nifty 50 option IV gives a "bank premium" signal - when banks are expected to be more volatile than the broader index, their IV premium widens. Similarly, comparing the IV of individual bank stock options against Bank Nifty index IV can highlight stock-specific vs. sectoral risk pricing.

Practical Steps for Integrating Chain Analysis Into Your Trading Process

Understanding the theory of options chain analysis is one thing; building it into a consistent, disciplined process is another. Here is a practical framework that many experienced traders follow when incorporating chain analysis into their daily or weekly workflow.

Morning Preparation (Before 9:15 AM IST) Before the market opens, review the previous session's final OI distribution on the chain. Note the call wall and put wall - the strikes with the highest OI. Calculate or look up the max pain level. Check India VIX relative to its recent range. If a major event is scheduled (RBI policy, Index rebalancing, FII data, global overnight news), note the event's potential impact on IV and position accordingly.

First 30 Minutes (9:15 AM – 9:45 AM IST) The opening 30 minutes are often volatile and driven by overnight gap adjustments. OI data in this period can be noisy. Many experienced traders prefer to observe without acting on OI signals during this window, instead watching how the chain's IV shifts from the previous close to the opening print. A sharp IV expansion in the opening indicates elevated uncertainty; IV contraction suggests the market is comfortable.

Core Session Monitoring During the main session, track: (1) Change-in-OI at the nearest call and put strikes relative to spot - are the walls building or collapsing? (2) PCR-OI trajectory - is it rising (more put OI building) or falling? (3) ATM IV direction - is premium expanding or contracting? (4) Futures price relative to spot - a high futures premium (high cost of carry) suggests strong bullish carry; a low or negative premium (backwardation) suggests bearish near-term sentiment.

Integrating Chain Signals With Price Action Chain analysis is most powerful when it confirms price action, not when it contradicts it. If the price is approaching a well-established call OI wall but momentum indicators (like RSI or MACD) are overbought and volume is declining, the probability of the wall holding is higher. Conversely, if momentum is strong and the call wall OI is shrinking, the probability of a breakout increases. Always cross-reference.

Risk Management Reminder No amount of chain analysis eliminates risk. Options are leveraged instruments. A single contract error - wrong strike, wrong expiry, wrong direction - can result in losses that exceed the initial premium paid (for buyers) or theoretically unlimited losses (for naked writers). Every trade taken after chain analysis should have a pre-defined maximum loss. SEBI's investor education materials consistently emphasise that derivatives are complex instruments and are not suitable for all investors. Understanding the chain is necessary but not sufficient - sound position sizing and risk discipline are equally important.

Record-Keeping and Review Keep a trading journal that includes a screenshot or note of the OI ladder at the time of each trade, alongside the rationale. Over time, reviewing these records will reveal which chain signals have been reliable in your specific trading style and which have been misleading. This personalised, evidence-based calibration is far more valuable than any generic rule about OI interpretation.

Example

Key benefits

How it works

1. 1
   Access the Chain for Your Chosen Underlying and Expiry

   Open your broker terminal or NSE's website and select the underlying (Nifty 50, Bank Nifty, or a specific stock) and the expiry date. The chain will display all listed strikes with live data.

2. 2
   Identify the ATM Strike and Set Your Context

   Locate the at-the-money strike (closest to the current spot price). Note the current ATM IV and compare it against India VIX or recent historical IV levels to assess whether options are cheap or expensive.

3. 3
   Read the OI Ladder - Call Wall and Put Wall

   Scan the call OI column upward and the put OI column downward to find the strikes with the highest cumulative OI. These are your call wall (potential resistance) and put wall (potential support) for the current expiry.

4. 4
   Analyse Change-in-OI for Direction of Positioning

   Review the change-in-OI column to determine whether the walls are building (fresh positions) or collapsing (unwinding). Building walls strengthen the support-resistance hypothesis; collapsing walls weaken it.

5. 5
   Calculate or Note the PCR and Max Pain

   Divide total put OI by total call OI for the PCR. Look up or calculate the max pain strike. Together, these give you a sentiment summary and a theoretical gravitational centre for expiry-week price action.

6. 6
   Assess the IV Skew Across Strikes

   Compare IV levels across OTM call and put strikes. A steep put skew confirms institutional hedging demand; an unusual call skew may signal speculative bullishness. Use this to judge relative option pricing.

7. 7
   Cross-Reference With Price Action and Set Risk Parameters

   Confirm chain signals with price action, volume, and broader market context before acting. Define your maximum loss on any trade, set stop-losses, and never size positions beyond your risk tolerance.

Formula

PCR-OI = Total Put Open Interest ÷ Total Call Open Interest
Max Pain = Strike price where [Sum of ITM Call Payouts + Sum of ITM Put Payouts] is minimised

Key takeaways

Frequently asked questions

Related terms