Two measurements, two scopes
A straddle uses a call and put at the same strike and expiry. OI PCR usually aggregates many strikes in the selected chain. A move in the selected straddle can therefore occur without a similar move in chain-wide PCR.
VWAP provides a session reference for premium. It does not change the PCR calculation. Underlying price, premium and PCR have different units; crossing lines on separate axes does not mean equal values.
Screenshot: premium and positioning context
- Straddle premium. The combined call and put premium is a price, not a PCR reading.
- VWAP reference. VWAP is a separate premium reference; verify the selected contracts and session.
- PCR series. PCR is a unitless ratio with its own scale. It should not be numerically compared with premium or spot.
Read premium and PCR together
- Select the underlying, expiry, strike and session. Confirm the preview or live state.
- Identify the premium, VWAP and PCR labels before comparing their shapes.
- Read premium changes against the selected strike and underlying movement. A fixed strike can move away from ATM.
- Read PCR with its actual chain coverage. Inspect strike-level OI when it moves sharply.
- Compare a matched snapshot in the table or tooltip, then use the separate PCR and straddle guides if a difference needs explanation.
Worked example: one change does not explain the other
Suppose a straddle falls from 200 to 180 points while OI PCR rises from 0.9 to 1.1. Premium fell and outstanding OI shifted toward puts relative to calls. Those two observations do not establish whether the cause was time decay, IV, spot movement, new put OI or call unwinding. Check the inputs separately.
Avoid a two-line trading rule
Simultaneous movements are not proof of causation or an entry signal. Illiquid legs, changing coverage and asynchronous snapshots can create apparent divergences. Position profit also depends on entry prices, actions and quantities.