Open Interest
The total number of outstanding futures contracts that have not been settled, delivered, or offset. A measure of market participation.
Open interest (OI) counts the total number of open — i.e., unresolved — futures contracts in a given market. Every futures transaction involves a buyer and a seller; OI increases by 1 when a new long and a new short are created, and decreases by 1 when an existing position is closed.
OI is distinct from volume: volume counts all contracts traded in a session, OI counts those still outstanding at the end of the session. Rising OI alongside a price trend suggests new money entering, validating the move; falling OI during a trend suggests position liquidation.
OI is concentrated in the front month but migrates to the back month during the roll period.