How to Read an Option Chain — A Practical Guide
Every column, every row, every signal — what an option chain actually tells you and how to use it for entry, sizing, and exit. India-specific, with NIFTY and BANK NIFTY examples throughout.
An option chain is a table of all call and put strikes for an underlying, showing open interest, implied volatility, volume and price. Reading it well means using peak OI for support and resistance, the put-call ratio for sentiment, and max pain for the likely expiry pin — while avoiding the common misreads that trap new traders.
An option chain is a table. It lists every available strike for an expiry, with prices and open interest for both calls and puts. But beneath the table is a complete picture of how every market participant — retail, institutional, foreign, domestic — is positioned for the next few days or weeks.
This guide explains every column you'll see on a real NSE option chain, what each one is telling you, and how to read the chain as a whole. India-specific examples throughout — we'll use NIFTY 50 and BANK NIFTY weekly chains for most illustrations because they're the most liquid and most-traded.
By the end you should be able to look at any option chain and quickly identify: where institutions expect the underlying to settle, what the dominant resistance and support levels are, where positioning is one-sided (and potentially due for unwind), and whether implied volatility is rich or cheap relative to recent regime.
Anatomy of an option chain
A typical NSE option chain has calls on one side, puts on the other, strikes in the middle. For each strike you see: Last Traded Price (LTP), Bid/Ask, Volume, Open Interest (OI), OI Change, Implied Volatility (IV), and optionally Delta, Theta, Gamma, Vega.
LTP is the most recent traded price. Reflects current sentiment but is noisy on illiquid strikes.
Bid/Ask spread tells you liquidity. ATM strikes have spreads of ₹0.50-₹2; far OTM strikes can have spreads of ₹5+. Wide spreads make trading expensive.
Volume is contracts traded today. Tells you what's actively being positioned today.
Open Interest is total outstanding contracts (not yet closed). Tells you cumulative positioning over the life of the contract.
OI Change is the day's change in OI. Positive = new positions opened; negative = positions closed.
Reading open interest — the most important column
OI tells you where positioning is concentrated. The strike with the highest call OI is the level where the most call writing has happened — historically acts as resistance for the current expiry. The strike with the highest put OI is the level where the most put writing has happened — historically acts as support.
Worked example. Suppose it's a few sessions before BANK NIFTY's monthly expiry and BANK NIFTY is at 46,200. The option chain shows the highest call OI is at the 46,500 strike, and the highest put OI is at the 46,000 strike. Reading: institutions are most heavily positioned for BANK NIFTY to settle between 46,000 and 46,500 into the last-Tuesday expiry. That's your 'expected range' going into expiry day.
OI change column tells you positioning today specifically. If today's biggest OI change is +50,000 contracts at the 46,500 call strike, fresh call writing is heavy at that strike — bears are positioning for resistance to hold. If today's biggest OI change is -50,000 at the 46,500 call strike, call writers are covering — bulls are gaining the upper hand.
Implied volatility — pricing the unknown
IV is the market's estimate of how volatile the underlying will be from now until expiry. Higher IV = more expensive options. Lower IV = cheaper options.
The IV smile. ATM strikes usually have the lowest IV. As you move OTM in either direction, IV rises. The shape of this curve (the 'volatility skew') tells you about market fear: when OTM puts are priced at much higher IV than OTM calls, traders are paying up for downside protection — a sign of bearish hedging.
IV vs Historical Volatility (HV). If IV is much higher than recent realised HV, options are expensive — favours selling premium. If IV is lower than HV, options are cheap — favours buying premium. Strota's chain shows both.
IV before events. IV typically rises in the days leading up to known catalysts (RBI policy, earnings, election results) and crashes after the event. Trading around this pattern is one of the cleanest edges in Indian options markets.
PCR — the sentiment thermometer
Put-Call Ratio = total put OI divided by total call OI. A higher number means more put open interest relative to call open interest.
PCR is most useful as a sentiment thermometer at extremes. Below 0.7 is typically over-bullish (everyone's positioned long — vulnerable to a correction). Above 1.5 is typically over-bearish (everyone's positioned short — vulnerable to a short squeeze).
The 5-day PCR trend matters more than today's snapshot. Rising PCR over 5 sessions = institutions are buying protective puts = caution. Falling PCR = put unwinding = confidence.
Sector PCR comparisons. Compare NIFTY PCR vs BANK NIFTY PCR vs FIN NIFTY PCR. Divergence often signals sector rotation. BANK NIFTY PCR at 1.6 while NIFTY PCR is at 0.9 means institutional hedging is concentrated in banking specifically.
Max pain — where the market 'wants' to settle
Max pain is the strike at which the largest aggregate value of options expires worthless. Computed by summing intrinsic value of all open calls and puts at every candidate strike and finding the strike with the minimum total.
Theory: option writers (often institutional) have incentive to defend max pain because they profit when options expire worthless. On expiry day this gravity is real — BANK NIFTY settles within 100-200 points of max pain into a majority of its monthly (last-Tuesday) expiries.
Use max pain as one data point alongside the highest-OI strikes. When max pain aligns with both the highest-call-OI strike (resistance) and the highest-put-OI strike (support), the signal is strongest.
Don't use max pain in isolation as a forecast. Big news days override the pin gravity.
Common misreads
- Treating OI alone as directional. OI tells you positioning concentration, not direction. Combine with OI change to see today's flow.
- Reading PCR as a daily snapshot. It's the 5-day trend that matters — rising PCR signals caution, falling PCR signals confidence.
- Assuming max pain will hold through news days. Big news overrides the pin gravity — max pain is a tendency, not a forecast.
Key takeaways
- Open interest tells you cumulative positioning. OI change tells you what's happening today.
- Highest call OI strike usually acts as resistance for the current expiry; highest put OI as support.
- IV measures option expensiveness — compare to historical volatility to see if options are rich or cheap.
- PCR is most useful at extremes (>1.5 or <0.7) and as a 5-day trend, not as a daily snapshot.
- Max pain is the strike that hurts option buyers most — has real gravity on expiry day but isn't a forecast.
- Always check liquidity (bid-ask spread) before trading any strike — wide spreads kill option strategies.
Reading the chain — practical
What does 'open interest' mean in an option chain?
Open interest is the total number of outstanding contracts at a given strike — positions that haven't been closed yet. It accumulates over the life of the option contract and resets at expiry. High OI at a strike means many traders have positions there.
Is high open interest bullish or bearish?
Neither, on its own. High OI just means heavy positioning. What matters is the type of positioning — heavy call writing at a strike is bearish (sellers betting price stays below); heavy call buying is bullish. You usually have to read OI change alongside today's volume to figure out which side is driving it.
What's the difference between volume and OI?
Volume is contracts traded today. OI is cumulative outstanding contracts. A strike can have huge volume but small OI if traders are opening and closing same-day. Or it can have small volume but huge OI if positioning was built up weeks ago and is being held.
How do I use an option chain to find support and resistance?
The strike with the highest call OI typically acts as resistance for the current expiry — that's where heavy call writing has happened, so writers are motivated to defend it. The strike with the highest put OI typically acts as support. These aren't hard floors and ceilings, but they're the levels institutions are positioned around.
What is a 'volatility skew'?
The shape of the IV curve across strikes. ATM strikes usually have the lowest IV; OTM strikes have higher IV. When OTM puts are much more expensive (higher IV) than OTM calls, traders are paying for downside protection — a sign of bearish hedging. Steep skew = high fear; flat skew = complacency.
Should I use weekly or monthly option chains?
Weeklies are best for short-term directional trades and expiry-day strategies. Monthlies have more Vega and are better for volatility trades around known catalysts. Most active retail trading happens on weeklies; institutional hedging is split between both.