Call vs Put OI Analysis

Comparing call (CE) and put (PE) open interest by strike shows where option writers and holders have built positions. Heavy put OI below the spot usually acts as support because put writers defend that level, while heavy call OI above the spot often acts as resistance because call writers cap rallies. The balance between the two sides is a quick read of whether positioning favours upside or downside.

Strikes run along one axis with call OI on one side and put OI on the other, so the tallest bars mark the strikes with the most open contracts. Compare those peaks against the underlying price: the highest call OI strike is a common resistance candidate and the highest put OI strike a common support candidate. Then switch to the OI Change view to see whether positions are being added or unwound during the session.

The OI-based put call ratio (PCR) is total put open interest divided by total call open interest across the strikes you have selected. A PCR of 1.2 means put OI is 20% larger than call OI. The chart also offers a volume-based PCR, which uses the same formula on traded volume instead of outstanding contracts and reflects intraday aggression rather than standing positions.

Readings between roughly 0.9 and 1.1 are typically treated as neutral. A high PCR (above about 1.3) signals bearish sentiment that many traders treat contrarily as a bullish extreme, while a low PCR (below about 0.7) signals complacency that can precede corrections. Thresholds are guides, not signals on their own — compare the current PCR with its recent range for the same underlying and expiry.

Fresh put OI building below the spot usually means new positions at that strike — most often put writers selling downside, which they defend so the option expires worthless. That strike then tends to act as support. If price approaches and put OI starts falling instead, writers are covering and the support is weakening.

Building call OI above the spot is commonly call writers selling upside, which obliges them to sell the underlying if tested — creating supply that caps the move. That strike behaves as resistance. Watch whether call OI keeps building as price approaches (resistance holding) or unwinds (short covering that can accelerate the breakout).

Volume counts contracts traded during a session, so it resets to zero every day. Open interest counts contracts that remain outstanding, showing where positions actually sit and how they change as traders add, roll or exit. Volume tells you where activity happened today; OI tells you where commitment has accumulated across the expiry.

As expiry approaches, out-of-the-money strikes with little chance of finishing in the money lose OI as writers close positions and premium decays, so the OI distribution concentrates around the strikes near the spot. Heavy unwinding on one side often signals writers booking profits and can pull price toward the level of highest remaining OI. Weekly expiries show this compression faster than monthly contracts.

When both sides build at the same time, writers are usually selling both calls and puts — expecting the underlying to stay inside the range between the two OI peaks. This is typical straddle and strangle writing before events or in low-volatility regimes. The market is pricing a range until one side starts unwinding or price breaks beyond the dominant strike.

In live mode the chart refreshes every 3 minutes during market hours. Use the integrated date picker to load any past session and replay how call vs put OI, OI change and PCR evolved through that day — useful for backtesting how positioning shifted before a move happened.