The Basic Layout

An option chain lists every available strike price for a given underlying and expiry, with call option data on one side and put option data on the other, typically arranged around a central column showing the strike prices themselves. Each row represents one strike, and reading across that row from the call side to the put side gives a complete picture of how the market is pricing both the right to buy and the right to sell at that specific price.

Last Traded Price and Change

The most basic columns show the last traded price (LTP) for each option and the change from the previous session’s close, giving an immediate sense of which strikes are seeing meaningful price movement. A large percentage change in a specific strike’s LTP, especially compared to neighbouring strikes, often signals where fresh positioning is concentrating during that session, ahead of any deeper analysis of volume or open interest.

Bid, Ask, and the Spread

The bid price is the highest price a buyer is currently willing to pay; the ask price is the lowest price a seller is currently willing to accept. The gap between them, the bid-ask spread, is a direct measure of that strike’s liquidity — a tight spread of a few paise indicates an actively traded, easily executable strike, while a wide spread of several rupees signals thin liquidity where entering and exiting positions will incur meaningfully higher transaction costs.

Volume: Today’s Activity

Volume shows how many contracts of that specific strike have traded during the current session, resetting to zero at the start of each new trading day. High volume relative to a strike’s typical activity often indicates that strike is currently in focus — potentially due to news, a technical level nearby, or a large institutional order working through the market — and is worth cross-referencing against price action at that level.

Open Interest: Accumulated Positions

Open interest (OI) represents the total number of outstanding, unsettled contracts at that strike, accumulated across all sessions until they are closed, exercised, or expire. Unlike volume, open interest does not reset daily, making it the better metric for judging where meaningful positioning has built up over time. A strike with unusually high open interest relative to neighbouring strikes is often treated as a significant support or resistance level, since a large number of participants have real capital committed there.

Change in Open Interest

This column, showing how much open interest increased or decreased from the previous session, is arguably more informative than the raw open interest figure alone, since it reveals whether fresh positions are actively being built or existing positions are being unwound at that specific strike right now. A sharp rise in open interest at a specific call strike, especially combined with a falling or flat price at that strike, is often read as fresh call writing — a bearish signal for that level.

Implied Volatility Per Strike

Most option chains display implied volatility for each individual strike, and experienced traders scan across strikes for a phenomenon called volatility skew — where out-of-the-money puts often show noticeably higher implied volatility than equivalent out-of-the-money calls, reflecting the market’s tendency to price downside protection more richly than equivalent upside speculation, particularly in equity index options.

Identifying the At-the-Money Row

Most platforms highlight or centre the option chain around the at-the-money strike — the strike closest to the underlying’s current price — since this is typically where the most liquid trading, the tightest spreads, and the most actively watched open interest changes are concentrated. Scanning outward from this central row in both directions gives a structured way to assess how positioning and pricing evolve as strikes move further in or out of the money.

Scanning the Chain Like a Professional

Rather than reading every cell individually, experienced traders scan an option chain with a specific sequence: first checking where the largest open interest sits on both the call and put sides to identify likely support and resistance zones, then checking the day’s change in open interest to see where fresh money is flowing, then checking implied volatility for any unusual spikes at specific strikes that might indicate anticipated news, and finally cross-referencing all of this against the underlying’s current price action.

The Bottom Line

An option chain is dense with information once you know what each column actually represents — price and its change reveal current sentiment, volume reveals today’s focus, open interest reveals accumulated positioning, and implied volatility reveals the market’s pricing of future uncertainty. Learning to scan a Nifty or Bank Nifty option chain systematically, rather than staring at the whole grid at once, turns an intimidating wall of numbers into a genuinely useful daily research tool.