Open Interest

The number of futures or options contracts still open, a gauge of market participation.

Overview

Open interest counts outstanding contracts that have not been closed by offset, delivery or exercise. Each contract has one long and one short, so it measures positions rather than traders. It rises when new buyers and sellers open positions and falls when they close them. Exchanges publish it daily by contract month, and traders read it alongside volume: rising prices with rising open interest suggest fresh money confirming a trend, while falling open interest suggests short covering or liquidation. Open interest migrates from expiring to deferred months during roll periods, and very large positions relative to open interest draw position limit scrutiny and fears of a squeeze.