How to read open interest without fooling yourself

Open interest tells you how many contracts are outstanding. It does not tell you who is winning. Here is the small set of interpretations that survive scrutiny — and the popular ones that do not.

Open interest is one of the most quoted and least understood numbers in Indian derivatives commentary. It is simply the count of contracts that remain open. Every contract has a buyer and a seller, so open interest by itself carries no directional information at all.

The four combinations

Interpretation only begins when open interest is paired with price:

• Price up, OI up — new money entering on the long side. The move has participation behind it.
• Price up, OI down — short covering. The move is real but its fuel is finite.
• Price down, OI up — new shorts building. Weakness with conviction.
• Price down, OI down — long unwinding. Sellers are leaving, not arriving.

Where people go wrong

The most common error is reading a large open interest at a strike as a "wall" that price cannot cross. Strikes with heavy open interest often act as magnets, not barriers, and they are re-hedged continuously. The second error is comparing today's open interest to yesterday's without adjusting for expiry cycles and rollover.

What to pair it with

Open interest is most useful alongside volume and implied volatility. A rise in open interest with flat volume is positioning; a rise with heavy volume is conviction. A rise in open interest with collapsing implied volatility usually means writers, not buyers, are doing the work.

Derivatives are leveraged instruments and can result in losses exceeding the margin deposited. This article is educational and is not a recommendation.

Published 03 August 2026 · 2 min read · 244 words