Open Interest (OI) measures market participation and liquidity in derivatives. It counts the total number of open (unresolved) contracts at any point in time.

OI vs Volume

  • Volume: Number of contracts traded in a session (resets to 0 daily)
  • Open Interest: Cumulative outstanding contracts (carries forward)

Interpreting OI

PriceOpen InterestInterpretation
RisingRisingStrong uptrend (new longs entering)
RisingFallingShort covering (weak signal)
FallingRisingStrong downtrend (new shorts entering)
FallingFallingLong liquidation (weak signal)