Open Interest & Put-Call Ratio
Reading positioning from how many contracts are open and the balance of puts to calls.
Beyond price and volatilityThe size of price swings — not their direction., optionsThe right, not the obligation, to buy or sell at a set price. data reveals positioning — what the crowd is actually betting on. Two widely watched gauges: open interestThe number of derivative contracts still outstanding. (OIThe number of derivative contracts still outstanding.) and the put-call ratio (PCR)Put volume (or OI) divided by call volume..
- Open interestThe number of derivative contracts still outstanding. (OIThe number of derivative contracts still outstanding.) — the total number of outstanding (not-yet-closed) contracts at a strikeThe fixed price at which an option can be exercised.. Unlike volumeThe number of shares or contracts traded in a period. (a day’s trades), OI shows how many positions are currently held — i.e. where the crowd is committed.
- Put-call ratio (PCR)Put volume (or OI) divided by call volume. — total putThe right, not the obligation, to buy or sell at a set price. OIThe number of derivative contracts still outstanding. (or volumeThe number of shares or contracts traded in a period.) divided by total callThe right, not the obligation, to buy or sell at a set price. OIThe number of derivative contracts still outstanding.. PCRPut volume (or OI) divided by call volume. > 1 means more putsThe right to sell the underlying at a set price — a bearish bet. than callsThe right to buy the underlying at a set price — a bullish bet. outstanding; PCR < 1 means more callsThe right to buy the underlying at a set price — a bullish bet..
These tools read the crowd’s positioning — and there are two ways to interpret them, which is where nuance matters. First, **supportPrice zones where buying (support) or selling (resistance) tends to dominate./resistancePrice zones where buying (support) or selling (resistance) tends to dominate.**: strikes with huge OIThe number of derivative contracts still outstanding. often act as price magnets and barriers, because optionThe right, not the obligation, to buy or sell at a set price. sellers there have an incentive to defend those levels (e.g. a massive callThe right, not the obligation, to buy or sell at a set price.-OIThe number of derivative contracts still outstanding. strikeThe fixed price at which an option can be exercised. can cap a rally). Second — and counter-intuitively — PCRPut volume (or OI) divided by call volume. is often read as a **contrarianGoing against the crowd’s prevailing sentiment.* indicator: an extremely high* PCRPut volume (or OI) divided by call volume. (everyone bought putsThe right to sell the underlying at a set price — a bearish bet., max bearishness) can signal a market bottom (the selling is exhausted), while an extremely low PCR (max greedThe two emotions that move markets and ruin accounts.) can warn of a top. When everyone is positioned one way, there’s no one left to push it further. So OI shows you where the crowd is committed, and PCR extremes whisper that the crowd may be too one-sided — a classic contrarianGoing against the crowd’s prevailing sentiment. tell.
ExampleNiftyA basket of stocks tracked together to represent a market. shows enormous callThe right, not the obligation, to buy or sell at a set price. OIThe number of derivative contracts still outstanding. at 22,500 and huge putThe right, not the obligation, to buy or sell at a set price. OIThe number of derivative contracts still outstanding. at 22,000 — a likely trading range, with 22,500 acting as resistancePrice zones where buying (support) or selling (resistance) tends to dominate. (callThe right to buy the underlying at a set price — a bullish bet. sellers defending) and 22,000 as supportPrice zones where buying (support) or selling (resistance) tends to dominate.. Meanwhile PCRPut volume (or OI) divided by call volume. spikes to 1.8 (extreme putThe right to sell the underlying at a set price — a bearish bet.-buying) right at a panic low — read contrarily, the bearishness is so crowded it often precedes a bounce.
Common mistakeReading a high PCRPut volume (or OI) divided by call volume. as simply “bearish, so sell.” At extremes, PCRPut volume (or OI) divided by call volume. is usually a *contrarianGoing against the crowd’s prevailing sentiment.* signal — extreme bearishness often marks a bottom, not a continuation. Use PCR as a sentiment-extreme gauge, not a naive trendThe prevailing direction of price: up, down or sideways.-following one, and combine it with price action.
Key takeawayOpen interestThe number of derivative contracts still outstanding. shows where the crowd is committed (big-OIThe number of derivative contracts still outstanding. strikes act as supportPrice zones where buying (support) or selling (resistance) tends to dominate./resistancePrice zones where buying (support) or selling (resistance) tends to dominate. magnets); the putThe right, not the obligation, to buy or sell at a set price.-callThe right, not the obligation, to buy or sell at a set price. ratio gauges sentiment. At extremes, PCRPut volume (or OI) divided by call volume. is often a *contrarianGoing against the crowd’s prevailing sentiment.* tell — too many putsThe right to sell the underlying at a set price — a bearish bet. can mark a bottom, too many callsThe right to buy the underlying at a set price — a bullish bet. a top. Read positioning, not just price.
FAQs
What’s the difference between open interest and volume?
Volume is the number of contracts *traded* in a period; open interest is the number of contracts *currently open* (not yet closed or expired). Rising OI with rising price suggests new money backing the move; volume spikes show activity, but OI shows lasting commitment. Together they reveal whether a move has real positioning behind it.