How to read an option chain.
An option chain is the most data-dense table in retail trading. Read column by column, it tells you where positions are concentrated, where writers are defending, and where the next move probably won't happen. Read carelessly, it's noise.
What an option chain actually is
For every underlying — NIFTY, BANKNIFTY, BTC — an exchange lists option contracts at multiple strike prices for each expiry. The option chain is that listing, laid out as a table with strikes in the middle column and call data on one side, put data on the other.
Every row is one strike. Every cell is one piece of information about how many contracts are open at that strike, what they last traded at, and how that has changed today.
The standard layout
Most platforms present the chain in this order from left to right:
- Call Open Interest (Call OI)
- Change in Call OI
- Call Last Traded Price (Call LTP)
- Strike Price (centered)
- Put Last Traded Price (Put LTP)
- Change in Put OI
- Put Open Interest (Put OI)
Some platforms add volume, implied volatility, bid/ask, Greeks, or derived columns like per-strike PCR. The seven above are the core that every chain has.
Reading column by column
Strike Price
The center column. The price at which the option contract would convert if exercised. NIFTY strikes are typically 50 points apart; BANKNIFTY 100; SENSEX 100; BTC daily $250–$500 depending on volatility. The strike closest to current spot is the At The Money (ATM) strike.
ITM, ATM, OTM
Three flavors based on where spot sits relative to the strike:
- ITM (In The Money): a call is ITM when spot > strike. A put is ITM when spot < strike.
- ATM (At The Money): the strike closest to spot.
- OTM (Out Of The Money): the opposite of ITM. Most retail buying happens in OTM strikes because they're cheap.
Open Interest (OI)
The number of contracts currently active at that strike. Each open contract represents one buyer and one writer who haven't closed out. OI is the single most informative number in the chain. High OI = crowded strike. Where the crowd is positioned tells you where the market is committing capital.
In Indian markets, OI is shown in actual contract numbers (e.g., 1.2L = 120,000 contracts). On BTC, it's shown in BTC notional or in contract counts depending on the exchange.
Change in OI
The day-over-day delta. Today's OI minus yesterday's settlement OI. Positive change = fresh contracts opened today. Negative change = existing contracts closed today.
Combined with the underlying's price move, this gives you the OI Buildup classification:
Long Buildup
Price ↑, OI ↑ — fresh longs being added. Bullish.
Short Buildup
Price ↓, OI ↑ — fresh shorts being added. Bearish.
Short Covering
Price ↑, OI ↓ — shorts closing. Bullish but exhausting.
Long Unwinding
Price ↓, OI ↓ — longs closing. Bearish but exhausting.
Last Traded Price (LTP)
The price at which the most recent contract changed hands. LTP is informational but easily stale on illiquid strikes — a single trade an hour ago will still show as the LTP. For deep OTM strikes, LTP is often unreliable as a fair-value estimate; use bid/ask if available.
Volume
Number of contracts traded today at that strike. Volume tells you about flow (today's activity); OI tells you about position (cumulative commitment). High volume with low OI change = lots of in-and-out trading. High volume with rising OI = fresh positioning.
Implied Volatility (IV)
The volatility the market is pricing into the option, derived by inverting the Black-Scholes formula. IV varies by strike — typically higher for OTM strikes (the "volatility smile" or "skew"). Compare IV across strikes for the same expiry, and across expiries for the same strike, to see how the market is pricing risk.
The single most important pattern: where OI clusters
Forget every other column for a moment. Just look at where Call OI and Put OI are concentrated.
- Strike with highest Call OI is typically treated as resistance — call writers are defending that level by selling those calls.
- Strike with highest Put OI is typically treated as support — put writers are defending it.
- The range between these two strikes is the market's implied "expected range" for the underlying through expiry.
This is the simplest, most reliable read of the chain. Everything else refines this picture.
How spot price interacts with the chain
As spot moves, the ATM strike shifts. The chain "breathes" around the current spot:
- Spot rallying toward the highest-Call-OI strike → that strike may either hold (resistance confirmed) or break (writers stopped defending).
- Spot falling toward the highest-Put-OI strike → same logic in reverse.
- Spot crossing either level → fresh OI builds at new strikes, the "range" expands.
Per-strike PCR
On most platforms a small bar at each row visualizes Put OI / Call OI at that specific strike. Per-strike PCR is more localized than overall PCR — a strike with high local PCR is acting as support locally even if the broader chain is mixed.
Common chain-reading mistakes
"High OI = bullish/bearish"
OI is neutral. High Call OI could mean writers are confident the strike won't break (bearish for that move) or buyers are confident it will (bullish). You need context — usually price action and change in OI direction — to determine which.
"Spot above Max Pain = bullish"
Not directly. Spot above max pain just means the market is currently sitting above the writer-comfort anchor. Combined with rising call OI on the strike above, it can be a continuation signal. Combined with rising put OI on the same strike, it can be reversal pressure.
"Cheap OTM options are good buys"
Cheap OTM options usually expire worthless. Premium is cheap because the probability of profit is low. Buying far-OTM weekly options is one of the highest-loss-rate strategies in retail options.
Ignoring change in OI
Absolute OI tells you positioning. Change in OI tells you flow. Strikes where positioning is large but flow is flat are "stuck" — yesterday's story. Strikes where flow is large are today's story. Always look at both.
Practical workflow
- Identify spot and ATM. Look at the chain centered around ATM ±5–10 strikes.
- Find highest Call OI and highest Put OI. Mark those as resistance and support.
- Compute or read overall PCR. Is the chain leaning?
- Find Max Pain. Is spot near it or pulling away?
- Check change-in-OI direction at the key strikes (ATM, max-OI strikes, max pain). Is fresh positioning aligned with current price action?
- Form a view, define your risk, and act.
How RetailInterest displays the chain
The live terminal shows the full strike grid sorted by strike. ATM is
highlighted, Max Pain is tagged MAX, Spot strike is tagged
SPOT, and computed Entry/Exit/Resistance markers are
overlaid as E1, E2, TP, and
RES. Per-strike PCR bars sit alongside each row. The whole
chain refreshes every three seconds.
FAQ
What is an option chain?
A tabular listing of all available option contracts for a given underlying and expiry, with call and put data shown side by side for each strike.
What is ATM in option chain?
At The Money — the strike closest to current spot price. For NIFTY at 23,478, the ATM strike is 23,500 if strikes step in 50s.
What does Call OI mean?
Call Open Interest — the number of call option contracts currently outstanding at a particular strike. High Call OI usually marks resistance.
How do I read Change in OI?
Positive = fresh positions opening today. Negative = positions closing. Combined with the underlying price move, this gives OI buildup type.
Why does my chain have blank cells?
Illiquid strikes (typically far OTM) with no recent trades show empty LTP and zero/low OI. That's normal.
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