Updated · BreakPoint Research Desk
Open interest (OI) is the number of futures or options contracts that are still open. It rises when a new buyer and a new seller create a contract and falls when an existing buyer and seller close one. It measures participation that stays in the market, unlike volume, which counts every trade.
Read with price, OI gives four common interpretations: price up + OI up = long buildup; price down + OI up = short buildup; price up + OI down = short covering; price down + OI down = long unwinding. New positions (rising OI) tend to support a move more than positions being closed (falling OI).
Key takeaways
In derivatives, one contract exists between one buyer and one seller. Open interest is the total of such contracts not yet squared off or expired. It is reported for each futures contract and for each option strike and expiry.
| Trade | Effect on OI |
|---|---|
| New buyer + new seller | OI rises by one contract |
| Existing buyer sells to a new buyer | OI unchanged (position changes hands) |
| Existing seller buys back from a new seller | OI unchanged |
| Existing buyer sells to existing seller (both close) | OI falls by one contract |
Volume counts all four trades above. That is why a day can have huge volume but little change in OI — lots of positions changed hands without new commitment.
| Combination | Usual reading | What to watch |
|---|---|---|
| Long buildup (price ↑, OI ↑) | New long positions entering; move has fresh support | Whether OI keeps rising as price extends |
| Short buildup (price ↓, OI ↑) | New short positions entering; move has fresh support | Sharp reversals if shorts get trapped |
| Short covering (price ↑, OI ↓) | Shorts buying back; rally driven by exits | Rallies that fade once covering is done |
| Long unwinding (price ↓, OI ↓) | Longs exiting; decline driven by exits | Selling that exhausts once longs are out |
Use futures OI for direction clues
For a stock or index, compare the change in price with the change in futures OI over the day or the week. This is where the four labels apply most directly.
Use option OI for levels
Option OI by strike shows where positions cluster, which traders read as potential support and resistance zones.
Look for confirmation on breakouts
A breakout with long buildup is often considered stronger than one driven only by short covering.
Be careful near expiry
In the last days before expiry, traders roll positions to the next month. OI in the near contract falls and OI in the next rises — that is rollover, not long unwinding.
Check the whole picture
Combine OI with the price chart, volume and market trend before acting on any label.
Stock A rises 3% and its futures OI rises 9%. Stock B rises 3% and its futures OI falls 7%. Both break their previous day high.
Stock A’s move came with new positions being opened — participants are committing to the upside. Stock B’s move came mostly from shorts buying back. B can keep rising while covering continues, but once shorts are out the buying pressure may fade. A trader looking for continuation would study A first and treat B’s breakout with more caution.
Same percentage move, different fuel. OI tells you which.
Thinking rising OI means “more buyers”
Every new contract has a buyer and a seller. Rising OI means more open positions, and price tells you which side is pressing.
Ignoring rollover week
Falling near-month OI before expiry is usually rollover. Look at combined OI across months.
Reading one interval in isolation
A 15-minute OI change can be noise. Look at the day and the trend over several days.
Trading labels without a chart
A long buildup at resistance can still fail. The label is context, not an entry.
Forgetting hedges
Institutions hedge cash positions with futures and options, which can create OI that says nothing about their directional view.
Calculating price and OI changes for every F&O stock yourself is slow. BreakPoint shows the open-interest context alongside price so you can compare moves quickly. How its tools rank or select symbols stays private.
The OI trend behind each move
OptionX pairs F&O stocks that are moving with the open-interest trend behind the move — separating new money from positions being closed (Pro 365).
Where OI is building market-wide
The F&O dashboard shows where open interest is building, how sentiment is shifting and where option sellers are getting trapped (Pro 365).
Index option OI by strike
Option Scanner shows where index call and put activity is concentrating through the session.
The BreakPoint mobile app lets you follow OI shifts during the day on your phone.
Futures traders
The four combinations apply most directly to futures price and OI.
Option traders
OI by strike and its changes frame the likely range and show where writers are active.
Cash-market swing traders
For F&O stocks, derivatives OI adds a useful check on whether a breakout has real participation.
Beginners
Learn the concept before relying on any label — misreading OI is common.
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Open interest is the number of futures or options contracts that are open and not yet closed or expired. It rises when new positions are created and falls when positions are closed.
It means new contracts are being opened — fresh participation. With rising price it is usually read as long buildup; with falling price, as short buildup.
Long buildup is when price rises and open interest rises together, suggesting new long positions are entering and supporting the move.
Short covering is when price rises while open interest falls, suggesting traders who were short are buying back to close positions. These rallies can be sharp but may fade once covering ends.
Long unwinding is when price falls and open interest falls, suggesting existing long positions are being closed.
Volume counts every contract traded during the day. Open interest counts contracts that remain open. High volume with little OI change means positions changed hands without new commitment.
Not by itself. Rising OI shows more open positions; whether that is bullish or bearish depends on the price direction and context.
Traders close or roll positions into the next expiry. The near-month OI falls while the next month’s OI rises, which is rollover rather than a directional signal.
Use OptionX and the F&O dashboard to see whether moves are backed by new positions or driven by exits, then check the chart.
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Terms used here: Open Interest (OI) · F&O (Futures & Options) · PCR (Put-Call Ratio) · Volume · Breakout
This article is for education only. It is not investment advice or a recommendation to buy or sell any security. Trading involves risk of loss; examples are hypothetical and past behaviour of any pattern does not guarantee future results.