Option Chain Explained: Reading a Nifty CE and PE Table

What an option chain actually is

An option chain is a single table that lists every options contract trading on one underlying for a chosen expiry. For each strike price it shows the call side and the put side together, so you can see at a glance what buyers and sellers are paying across the whole range of strikes. On the NSE you pull it up for an index such as Nifty 50 or Bank Nifty, or for a liquid stock such as Reliance, HDFC Bank, TCS or Infosys, and then pick the weekly or monthly expiry you want to study.

The chain is the fastest way to read positioning. Instead of guessing where the crowd is, you see the actual premium, the open interest and the implied volatility at every strike. That tells you which strikes are crowded, where writers are defending, and how expensive options are right now compared with their usual cost. A trader who can read a chain in ten seconds has a real edge over one who only watches the spot price.

The standard NSE layout puts call options (CE) on the left, put options (PE) on the right, and the strike prices running down the middle. As you move down the strikes the calls go from in the money to out of the money, while the puts do the opposite. The single most important reference point on the whole table is the at the money (ATM) strike, which is the listed strike nearest to the current spot.

A real Nifty option chain, read line by line

Below is an illustrative Nifty weekly option chain with spot at 23,512, so the ATM strike is 23,500. Calls are on the left, puts on the right, strikes in the centre. LTP is the last traded premium per unit, OI is open interest in number of contracts (in thousands here), Chg OI is the change since the previous close, and IV is implied volatility in percent. These figures are for learning, not a live quote.

Read the ATM row first. At the 23,500 strike the call and the put both trade near 152, which is normal when spot sits almost exactly on the strike, because the two are almost pure time value. Above the ATM the calls get cheaper (82, 41, 18.5) as they move out of the money, and below the ATM the same happens to puts. The deep in the money 23,300 call at 362 is mostly intrinsic value, since spot is already 212 points above that strike.

Now read the open interest. The heaviest call OI sits at 23,600 (61.2k and rising fast at +12.7k), which marks a likely resistance zone where writers expect the move to stall. On the put side the heaviest OI is at 23,500 (55.1k, +9.4k), marking the support the put writers are defending. When call OI builds above spot and put OI builds below, the market is bracketing a range, and the ATM strike often acts as a magnet into expiry.

Finally read implied volatility. Notice the put IV (12 to 14 percent) sits above the call IV (around 11 percent). That skew is normal for an index, because traders pay up for downside protection, so puts carry a fear premium. If you only looked at premium and ignored IV you would miss that the puts are structurally more expensive than the calls at the same distance from spot.

Finding the ATM strike and reading moneyness

The ATM strike is simply the listed strike closest to spot. With Nifty at 23,512 and strikes spaced 100 points apart, the ATM is 23,500. Everything else is defined relative to it. A call is in the money (ITM) when its strike is below spot, at the money at the ATM strike, and out of the money (OTM) when its strike is above spot. For puts it is the mirror image.

Moneyness controls how premium splits into intrinsic value and time value. An ITM option has real intrinsic value (the gap between spot and strike) plus time value. An ATM or OTM option is pure time value, which decays to zero by expiry if the spot does not move in your favour. This is why most beginners who buy cheap far OTM options lose: they are buying nothing but a melting ice cube of time value with a low probability of paying off.

Open interest and change in OI: where the money is sitting

Open interest is the total number of contracts that are open and not yet squared off at a given strike. It is a stock figure, not a flow figure, so it tells you how many positions are currently parked there. Change in OI is the more actionable number, because it tells you whether positions were added or unwound today. Rising OI with a rising price means fresh longs; rising OI with a falling price means fresh shorts.

• Heavy call OI above spot tends to act as resistance, because the writers of those calls profit if price stays below the strike and will often defend it.
• Heavy put OI below spot tends to act as support, for the mirror reason on the put side.
• A sudden jump in change in OI at one strike flags where smart money is positioning for the session, often around a known event.
• Falling OI alongside a price move signals short covering or long unwinding rather than fresh conviction, so the move may not sustain.

OI is also the cleanest read on liquidity. A strike with thousands of contracts of OI and high volume will have tight bid ask spreads, so you can enter and exit without bleeding to slippage. A far OTM strike with almost no OI may quote a tempting premium, but you can get stuck unable to exit at a fair price. Always check OI before you trade a strike, not just the premium.

Implied volatility and the volatility skew

Implied volatility (IV) is the market's forecast of how much the underlying will move, backed out of the option price itself. High IV means options are expensive because the market expects a big move; low IV means they are cheap. IV is not a direction call. It can spike before an event such as the RBI policy, the Union Budget or a stock's earnings, and then collapse the moment the news is out, which is the famous IV crush that burns option buyers even when they call the direction correctly.

In the chain above, put IV runs higher than call IV at equal distance from spot. That skew reflects demand for downside protection. Practically, it means selling expensive OTM puts can pay well in calm markets but carries fat tail risk, while buying cheap OTM calls is a low cost bet that only works on a real trend. Always compare today's IV with the instrument's own recent range. Buying when IV is already elevated stacks the odds against you.

A fully worked Nifty trade with lot size, STT and brokerage

Suppose you read the chain, expect Nifty to push toward 23,700 this week, and buy one lot of the 23,500 ATM call at a premium of 152. The Nifty lot size is 65, so one contract controls 65 units. Your cost to enter, before charges, is 152 x 65 = Rs 9,880. That premium is the most you can lose on a long call, no matter how far Nifty falls.

Say Nifty rallies and on a later day the same call trades at 240. You sell to close. Gross gain is (240 minus 152) x 65 = 88 x 65 = Rs 5,720. Now the charges, which are illustrative and broker dependent. On a discount broker, brokerage on options is typically a flat Rs 20 per order, so Rs 40 for the buy and sell legs together. STT on options is charged at 0.15 percent on the sell side premium value, which here is 0.15 percent of (240 x 65) = 0.15 percent of 15,600 = Rs 23.40. Add exchange transaction charges, GST at 18 percent on brokerage plus exchange charges, SEBI fees and stamp duty, which on a trade of this size run roughly Rs 30 to Rs 45 in total.

So a roughly 58 percent gain in the premium turns about Rs 9,880 of risk into roughly Rs 5,600 net after costs, in this illustrative case. Flip the scenario: if Nifty stalls and the call decays to 60 by expiry, you lose (152 minus 60) x 65 = Rs 5,980 plus charges, and if it finishes below 23,500 the call expires worthless and you lose the full Rs 9,880 premium plus the entry charges. That asymmetry, capped gain on the downside but full premium at risk, is the core trade off of buying options.

How Indian option taxes and STT actually work

This trips up almost every new F&O trader. Profit from futures and options is treated as business income, not capital gains. It is added to your total income and taxed at your applicable slab rate. The capital gains rates you may have read about, such as STCG of 20 percent or LTCG of 12.5 percent above Rs 1.25 lakh, apply to delivery equity and similar assets, not to your F&O book. Because F&O is business income, you can also set off related expenses and, in many cases, carry forward losses, subject to the conditions in the Income Tax Act.

Securities Transaction Tax (STT) on options is charged at 0.1 percent of the premium on the sell side of an options trade. If an option is exercised, STT is instead charged on the settlement value. Futures STT is charged on the sell side of the contract value at a lower rate. STT is a cost of trading, not a tax on profit, so you pay it whether the trade wins or loses. Always confirm the current STT rates on the NSE or your broker's contract note before you size a strategy, because these rates are revised from time to time.

• F&O gains: business income, taxed at your slab rate, not capital gains.
• STT on options: 0.1 percent of premium on the sell side (or on settlement value if exercised).
• Delivery equity for context: STCG 20 percent, LTCG 12.5 percent above Rs 1.25 lakh per year.
• GST at 18 percent applies on brokerage and exchange transaction charges, adding to your real cost.
• Keep every contract note. As business income, accurate records matter for set off, carry forward and audit thresholds.

Expiry mechanics: weekly and monthly

Nifty has a weekly expiry plus a monthly contract, and Bank Nifty trades on its own schedule, so always confirm the live expiry calendar on the NSE because the exchanges and SEBI have revised expiry days more than once. Weekly options live for only a few days, so their time value decays fast, and on expiry day the ATM premium can melt almost to zero in hours. That makes weeklies cheap to buy but brutal to hold, because theta works against the buyer every passing hour.

Monthly contracts give you more time and slower decay, which suits position trades and hedges. The trade off is a higher premium for the extra time value. As a contract nears expiry, the chain becomes more sensitive: small spot moves cause large percentage swings in ATM premium, and OI shifts violently as positions roll to the next expiry. Reading change in OI on expiry day tells you whether traders are squaring off or rolling forward.

Common mistakes when reading an option chain

• Buying a far OTM option only because the premium looks cheap, while ignoring that it is pure time value with a low probability of paying off.
• Reading premium without reading IV, so you overpay for options that are already expensive ahead of an event and then suffer IV crush.
• Trading a strike with thin OI and low volume, then being unable to exit at a fair price because the spread is wide.
• Treating OI walls as fixed support and resistance, when a strong trend or a big event can blow straight through them.
• Forgetting that F&O is taxed as business income and that STT plus charges eat into thin scalps, so a small gross gain can become a net loss.

The fix for all of these is discipline. Read the ATM row first, then OI to find the range, then IV to judge whether options are cheap or dear, and only then look at premium. Size positions against your full risk, which for a buyer is 100 percent of the premium, and log every trade so you can see your real edge after costs rather than guessing.

Where to get a live, reliable option chain

The authoritative source is the official NSE option chain, which publishes live CE and PE data, OI, change in OI, volume and IV for indices and stocks. Most brokers, including Zerodha, Upstox, Angel One and Groww, also render the chain inside their platforms with extra analytics. Whatever tool you use, treat the official exchange data as the reference, and always confirm contract specifications, lot sizes, expiry days and STT rates on the official source before you trade, since they change.

For deeper study, the NSE website and Zerodha Varsity both explain the mechanics in detail. The point of the chain is not to predict the market, which no tool can do, but to read positioning and pricing so your decisions are grounded in what traders are actually doing rather than in hope.

Sources and Further Reading

For authoritative data and further reading on this topic, refer to NSE Option Chain, NSE India and Zerodha Varsity. Always confirm current rules, rates and contract specifications on the official source before you trade.