The option chain is the busiest screen most traders look at and the least explained. Two columns of numbers either side of a strike price, updating constantly, and no obvious answer to what any of it means.
The useful thing to understand first is that a chain is a record, not a forecast. It tells you where positions have been built and what the market is currently paying for uncertainty. Everything sensible you can do with it follows from that, and every mistake people make with it comes from treating it as a prediction.
The layout, and why it is arranged that way
A chain is one table per expiry. Strike prices run down the centre. Everything to the left belongs to the call side, everything to the right to the put side, and the row nearest the current spot price is the at-the-money strike.
Each side repeats the same columns: last traded price, open interest, change in open interest, volume, and usually implied volatility. Some platforms add delta and theta.
Reading it left to right on a single row tells you what the market thinks about that one strike from both directions. Reading a single column down the strikes tells you where activity is concentrated. The second reading is the more useful one, and it is the one most people never do.
Open interest, and the mistake everyone makes with it
Open interest is the number of contracts currently outstanding at that strike. It rises when a new position is created and falls when a position is closed. It is not volume — volume counts what changed hands today, open interest counts what is still held.
The near-universal mistake is to read a large open interest number as a prediction. You will hear that heavy open interest at a strike on the call side means it will act as resistance. Sometimes the market behaves that way and sometimes it walks straight through, and the reason the rule is unreliable is that open interest does not tell you which side initiated the position.
Every contract has a buyer and a seller. A big number at a strike means a lot of positions exist there. It does not tell you whether they were opened by somebody expecting the level to hold, somebody hedging an entirely different exposure, or an institution running a spread across two strikes. Treat concentration as a place where a lot of money has an interest, not as a forecast of what price will do.
Change in open interest is the number that matters
The absolute open interest figure carries history in it. The change since the previous close is what tells you about today, and combined with the price move it is genuinely informative.
There are four combinations, and they have standard names:
| Price | Open interest | Called | Reading |
|---|---|---|---|
| Up | Up | Long buildup | New positions being opened on the upside; the move has fresh money behind it |
| Down | Up | Short buildup | New positions being opened on the downside |
| Up | Down | Short covering | Existing downside positions being closed; a rise driven by exits rather than conviction |
| Down | Up in puts, falling in calls | Long unwinding | Existing upside positions being abandoned |
The distinction that earns its keep is the second and third rows. A rally on rising open interest and a rally on falling open interest look identical on a price chart and mean quite different things. One is new money taking a view. The other is old positions being closed, which tends to exhaust itself once the covering is done.
Implied volatility across the chain
Implied volatility is the market's expectation of future movement, backed out of the current premium. Higher implied volatility means options are more expensive in real terms, whatever the rupee premium looks like.
Two things to watch. First, the level relative to its own recent range — the same 14% means something different in a market that has been sitting at 11% than in one that has been at 20%. Second, the shape across strikes. Implied volatility is usually not flat; out-of-the-money strikes on the downside typically price higher, because protection against a fall is in more demand than participation in a rise.
Before a scheduled event — results, a policy decision, a budget — implied volatility across the chain gets bid up as uncertainty is priced in. Once the event passes it collapses, and premiums fall with it even when direction was correct. That collapse is the most common way an options position loses money while being right, and the chain shows it coming if you look at implied volatility rather than only at price.
Put-call ratio, and how much to trust it
The put-call ratio divides open interest on the put side by open interest on the call side. Above one means more puts are outstanding, below one means more on the call side. It gets quoted constantly as a sentiment indicator, usually as a contrarian one.
Two honest caveats. It is a ratio of positions, not of opinions — a large put position may be a hedge held against a stock portfolio rather than a bearish view, and hedges behave nothing like directional bets. And the ratio is only meaningful against its own history for that instrument; a reading of 1.2 is high for one index and unremarkable for another.
Useful as one input among several. Not useful as a signal on its own, and anyone presenting it as one is skipping the caveats.
Max pain, briefly
Max pain is the strike at which the largest rupee value of outstanding options would expire worthless. The theory attached to it is that price tends to gravitate there by expiry.
Treat it as a curiosity rather than a tool. The calculation is a snapshot that moves as positions change through the week, the effect is weak and inconsistent in practice, and building a position around it means betting that a statistical tendency holds on the one specific expiry you have money on.
The chain in the last hour before expiry
India's weekly expiries mean this scene repeats every week, and the chain behaves differently in it.
Premiums on out-of-the-money strikes collapse towards zero as remaining time disappears. Implied volatility stops mattering, because there is almost no time left for volatility to act on. Open interest at strikes far from spot drains as positions are closed or left to lapse. And the at-the-money strike becomes extremely sensitive — a small move in the index produces a large percentage move in that premium, which is gamma showing up in the price rather than in a Greek column.
The practical consequence: numbers you would read as significant on Monday mean much less on Thursday afternoon. The chain compresses towards spot and everything else becomes noise.
Pulling the chain into Python
If you want to study the chain rather than watch it, the useful move is to store snapshots and compare them. Here is the shape of it with Kite Connect:
import pandas as pd
from kiteconnect import KiteConnect
kite = KiteConnect(api_key='your_api_key')
kite.set_access_token('your_access_token')
nfo = pd.DataFrame(kite.instruments('NFO'))
chain = nfo[(nfo['name'] == 'NIFTY') &
(nfo['segment'] == 'NFO-OPT') &
(nfo['expiry'] == chosen_expiry)]
symbols = ['NFO:' + s for s in chain['tradingsymbol']]
quotes = kite.quote(symbols)
rows = []
for sym, q in quotes.items():
inst = chain[chain['tradingsymbol'] == sym.split(':')[1]].iloc[0]
rows.append({
'strike': inst['strike'],
'side': inst['instrument_type'], # CE or PE
'ltp': q['last_price'],
'oi': q['oi'],
'volume': q['volume'],
})
df = pd.DataFrame(rows).pivot_table(
index='strike', columns='side', values=['ltp', 'oi', 'volume'])
print(df.sort_index().head(20))One thing to note: the quote gives you current open interest, not the change. To get change in open interest you store a snapshot at the previous close and subtract — which is the number the analysis above actually depends on, so it is worth building the snapshot habit early.
Live chain data and the ability to act on it both need a broker account with API access.
Reading a live chain needs a broker feed
Strikes, open interest and implied volatility all come from your broker. Account free to open
If you would rather learn derivatives properly than in fragments, the chain is one part of our Futures & Options Mastery course at Rs 10,000 — ten modules from contract mechanics through to option selling and risk. One payment, lifetime access, free demo on WhatsApp first.
We sell no tips and no signal group, we manage nobody's money, and we promise no returns. Options can lose money quickly and selling them can lose more than the premium received.
Disclosure: the account-opening link on this page is under Atul Shrivastava's Zerodha Authorised Person registration (NSE AP Reg: AP2516003481; Zerodha Broking Ltd. SEBI Reg: INZ000031633) and earns a revenue share. TheFinBaba is not a SEBI-registered Investment Adviser — this content is educational, not investment advice.
Frequently Asked Questions
What does open interest mean in an option chain?
The number of contracts still outstanding at that strike. It rises when new positions are created and falls when they are closed. Volume, by contrast, counts what changed hands during the session regardless of whether positions were opened or closed.
Does high open interest at a strike mean it will act as support or resistance?
Not reliably. Concentration tells you a lot of positions exist at that level, not who initiated them or why - a hedge and a directional bet look identical in the number. Sometimes price respects those levels and sometimes it goes straight through.
What is a good put-call ratio?
There is no universal number. It is only meaningful against its own recent history for that specific instrument, and it mixes hedges in with directional positions. Use it as one input among several rather than as a signal by itself.
Why did my option lose value when the index moved my way?
Usually a fall in implied volatility, especially just after a scheduled event, plus time decay. The chain shows this building up if you watch implied volatility rather than only the premium.
Where can I see the option chain in India?
The NSE website publishes it, and every broker platform shows it with live data. For analysis, pull it through your broker's API and store snapshots so you can compute change in open interest yourself.
How is change in open interest different from open interest?
Open interest is the running total and carries the whole history of that strike. Change in open interest is the movement since the previous close, and read together with the price move it tells you whether positions are being opened or closed today.
Related Reading
- Option Greeks explained with examples
- F&O taxation in India: ITR-3, turnover and audit
- Futures & Options Mastery - full syllabus
- Order types: market, limit, SL and SL-M
- All course fees, stated plainly
Disclaimer: TheFinBaba provides educational content only - this is not investment advice. Trading involves risk of loss.
