Open Interest Analysis

Open interest (OI) represents the total number of active contracts in a futures or options market at a given moment — specifically, the sum of all long positions (which equals the sum of all short positions, since every contract requires a buyer and a seller). When a new contract is initiated between two parties who are both entering fresh positions, open interest increases by one. When both parties close existing positions, open interest decreases. When one party closes an existing position against a new entrant, open interest is unchanged.

Historical analysis of open interest alongside price produced a set of interpretive frameworks widely adopted in commodity and futures markets. Rising price accompanied by rising open interest was interpreted as new money flowing into the market in the direction of the move, suggesting the price trend was attracting new participation. Falling price accompanied by rising open interest suggested new short positions were being established. Rising price alongside falling open interest was historically noted as a potential sign that the move was driven by short covering rather than fresh buying — a distinction considered significant because short covering does not require the same sustained commitment as new long positioning.

In equity options markets, open interest at specific strike prices provided insight into where large institutional positions were concentrated. Strike prices with unusually high call or put open interest were sometimes referred to as gamma walls or max pain levels, with historical studies examining whether expiration-date price behavior showed any tendency to gravitate toward or away from those concentrations.

Open interest data is published daily for futures markets by exchanges and aggregated weekly in the CFTC's Commitment of Traders report. Options open interest is available at the individual strike and expiration level through exchange feeds. Analysts historically combined open interest trends with volume, price action, and the COT classifications to form a composite view of market participation.