Historical Call vs Put OI Analysis

Call vs Put OI compares the total open interest on the call side with the total on the put side. When put OI rises faster than call OI, institutional writers are defending lower strikes, which is typically bullish positioning. When call OI builds faster, the ceiling is getting heavier and upside tends to stall. The chart shows where professional money is committing capital, in real time.

The formula is simple. PCR equals the total open interest of put options divided by the total open interest of call options on the same underlying. On Nifty, the historical range is roughly 0.8 to 1.3. Readings outside that band carry information; anything above 1.5 or below 0.5 is at the extreme end where contrarian signals tend to fire.

Use it as a sentiment gauge with a contrarian twist. Above 1.3 means heavy put writing (bullish — writers are confident the strike will hold). Below 0.7 means heavy call writing (bearish ceiling). The reason extreme readings often signal reversals is mechanical: when retail buys lots of puts, the market makers selling them hedge by buying the underlying, which can fuel an upward squeeze. Same logic in reverse below 0.5.

Volume measures trades that happen; OI measures positions that remain. A single trader can generate massive volume churning in and out, but OI only rises when net new positions are created. For gauging true directional commitment, OI is the cleaner signal — especially when compared call vs put to reveal which side is accumulating.

As expiry approaches, OI on out-of-the-money strikes typically collapses as those options roll off. ATM and ITM strikes retain more OI as they settle. The shape of the final-day Call vs Put OI distribution often hints at the settlement price — heavy put OI below spot suggests downward gravity; heavy call OI above suggests upward gravity.

Somewhat. The first hour captures institutional positioning commitment but is also the most volatile in terms of OI flow as positions open and close rapidly. The direction and slope of the first-hour reading is usually reliable; the absolute level stabilises by 10:30 AM as session positioning settles.

Parallel growth in both sides usually signals anticipated volatility — traders are positioning for a big move in either direction. This often happens before major events (budget, RBI policy, results week). The absolute side (calls or puts) that grows faster tells you the directional bias, but the parallel growth itself is a volatility signal.