The option chain shows where money is positioned, strike by strike, for any contract on the NSE. This guide covers what it is, what each column means, how to read open interest for support and resistance, and how to use the PCR, Straddle and Greeks views on the Option Chain widget on IBT-ProTrade.
What is an option chain?
An option chain lists every call option (CE) and put option (PE) contract of an underlying for a specific expiry. For each strike price it shows the premium (LTP), open interest, OI change, traded volume and implied volatility, with calls on the left, puts on the right and strikes down the middle.
It matters because institutions and large funds are typically option sellers. Seeing which strikes carry the most open interest lets you identify the levels large writers are defending.
Strikes shaded differently are ITM, in the money. The rest are OTM, out of the money. The highlighted chip marks the ATM strike, the one closest to spot.
Setting up: contract, expiry and strike range
Three selectors control everything you see. Contract switches between indices and individual stocks. Expiry picks the series to analyse, and note that indices carry weekly expiries while stocks are monthly only. Strike Range filters to strikes near the money or shows the full chain.
The header also shows DTE, days to expiry, and PCR, the put call ratio.
How to read open interest for support and resistance
Switch Mode to OI and the chain becomes a picture. Red bars show Call OI on the left, green bars show Put OI on the right. One chart plots total open interest for the expiry, the other plots today's OI change, separating existing positions from fresh ones.
The reading rule, as an analytical observation:
- The strike with the highest Put OI tends to act as support, since a large base of put writers has an interest in defending it.
- The strike with the highest Call OI tends to act as resistance, since call writers lose money above it.
While those walls hold, price tends to stay between them. A move beyond either one means large losses for the writers positioned there, which is why such levels are usually defended rather than surrendered quietly.
Reading PCR
PCR compares total put open interest to total call open interest. A reading above 1 means put OI outweighs call OI, generally reflecting heavier put writing. A reading well below 1 reflects heavier call writing.
Treat it as one input rather than a verdict. Interpretations differ across sources, and the number moves through the session.
Column by column: what every number means
| Column | What it tells you |
|---|---|
| Trend | Reads price and OI together. LB, long buildup, is price up with OI up. SB, short buildup, is price down with OI up. SC, short covering, is price up with OI down. LU, long unwinding, is price down with OI down. |
| OI | Outstanding contracts at that strike, showing how much conviction is parked there. |
| OI Change (%) | How OI moved from the previous close to now, separating fresh positioning from stale. |
| Volume | Contracts traded today, showing how active that strike is now. |
| Volume PCR / OI PCR | Put call ratio computed strike wise, giving sentiment at each level rather than for the whole chain. |
| LTP (%) | Last traded premium and its change. |
| IV | Implied volatility, the market's expectation of how much the underlying will move. |
| Strike | The exercise price, sorted down the centre, ITM shaded and ATM highlighted. |
Straddle mode
Switch Mode to Straddle and each row shows the CE and PE premiums combined as Total Premium, with the upper and lower breakeven for a straddle at that strike. The ATM row is worth reading even if you never trade a straddle, because the total premium there is the market's own estimate of how far the underlying could move by expiry.
Greeks mode
Select Greeks in the Mode menu to see how each option's price responds to conditions around it.
- Delta. How much the premium moves per point of the underlying. ATM options sit near 0.5.
- Gamma. How fast Delta changes as spot moves.
- Theta. Daily time decay as expiry approaches.
- Vega. Sensitivity to changes in implied volatility.
- Rho. Sensitivity to changes in interest rates.
Buyers watch Theta and Vega most closely. Sellers watch Delta and Gamma to manage risk.
Customising the chain
Open the settings icon to toggle OI bars, percentage change, price in lots and nearest future price, and to switch individual columns on or off. Scalpers can strip the chain down to Trend and OI. Positional traders can load the Greeks.
A four step routine
Step 1. Pick the contract and expiry, and note DTE and PCR.
Step 2. In OI mode, mark the highest Put OI strike and the highest Call OI strike.
Step 3. Check OI Change and the Trend column to see where fresh positions are being built today rather than where old ones sit.
Step 4. Read the ATM straddle premium for the expected range, then assess levels near the edges of the OI range rather than the middle.
Go deeper. Multistrike OI shows how positioning evolves at chosen strikes through the day, Open Interest maps the largest walls, Combined OI gives the market wide verdict, and Max Pain distils the same data into one expiry level.
