Option chain analysis: a practical guide

The option chain is the most information-dense table on an Indian trading terminal — every strike of NIFTY or BANK NIFTY, with open interest, volume and implied volatility on both sides. Option chain analysis is the craft of reading that table as a positioning map instead of a wall of numbers.

What the chain actually shows

The layout is standard: strikes run down the middle, call-option data sits on one side, put-option data on the other. For each strike and each side you get traded volume, implied volatility, open interest, and change in open interest. OI is the number of contracts currently open — one count per live buyer-seller pair. It is a standing stock of positions, not a flow.

Volume and OI answer different questions. Volume counts every trade during the day, including positions opened and closed within minutes. OI only rises when a genuinely new position is created and only falls when an existing one is closed. High volume with flat OI is churn; rising OI is commitment. Reading the two together, strike by strike, is what separates a chain reader from someone glancing at a table.

Why OI concentration matters

Every open contract has a seller. On Indian index chains, the selling side — the option writers — tends to be the larger, margined, hedged participants, because writing requires substantial capital and carries open-ended risk. So a strike with heavy OI is a strike where sizeable players have committed money and, usually, hedges. That is what makes strike-wise OI readable: it maps where capital is parked, strike by strike, on both the put and call side.

• Strike-wise OI, both sides: where put writers and call writers are concentrated relative to spot.
• OI change vs carried OI: today's positioning versus what was already there.
• Volume against OI: whether a strike is being traded or being held.
• IV per side: whether one side of the chain is being bid up relative to the other.

OI change vs static OI

A static OI snapshot mixes today's decisions with positions carried from previous sessions. The change-in-OI column separates them: it shows where writers are adding, and where they are unwinding, right now. Intraday, that distinction is most of the game — a strike whose OI is building through the morning is telling you something a week-old base of OI cannot. The related quadrant framework of long buildup and short buildup applies the same fresh-vs-closing logic to futures. Note that BANK NIFTY needs its own baselines — lot sizes, strike spacing and turnover all differ — so an OI figure that is heavy on one index can be routine on the other.

A positioning map, not a forecast

The chain shows where market participants have committed capital — it does not say what price will do next. Heavy OI at a strike describes positioning; the market is free to trade through it, and regularly does. Treat the chain the way you would treat order flow: an unusually precise picture of what participants are doing, on top of which your decisions remain entirely your own.

That is also the compliant framing: TBTflow displays chain-derived analytics — OI concentration, OI change, wall pressure — as descriptive data. The data shows positioning; it never tells anyone to buy or sell.