Open interest measures how much notional remains open in a futures or perpetual market. Rising OI with rising price can indicate new capital entering; falling OI may signal position unwind.
Understanding open interest
OI is not the same as volume. Volume counts traded notional over a period; OI is a stock of outstanding contracts at a point in time.
Traders combine OI with funding and basis to gauge crowded positioning. Crowded longs with high positive funding can unwind violently if price stalls.