Open InterestOI
Open interest (OI) is the total number of futures or options contracts that are open and not yet closed or settled; rising OI means new money entering positions.
Volume tells you how many contracts traded today. Open interest tells you how many are still open at the end of it.1 Every futures or options contract has a buyer and a seller, and it stays “open” until one of them closes it or it is settled. Watching whether open interest rises or falls alongside price shows whether new positions are being built or old ones unwound — a useful clue to what is driving a move, especially in futures and crypto derivatives.
- Category
- Derivatives
- Reading time
- 5 min
- Also called
- Open contracts, Open commitments, Rising open interest
- Updated
Open interest in plain words
Open interest is the number of futures contracts still outstanding in a market or delivery month — not yet closed by an offsetting trade or settled by delivery.2
Volume is different: it is the number of contracts traded during a period.2 A day can have huge volume and little change in open interest if traders are mostly closing and reopening positions.
How open interest changes, step by step
New buyer + new seller
Both open new positions: open interest rises by one contract.
New trader takes over an old position
A new buyer buys from an existing long who is closing: open interest is unchanged.
Both close
An existing long sells to an existing short who is buying back: open interest falls by one.
Compare with price
Rising price with rising OI suggests new longs entering; rising price with falling OI suggests shorts covering. See Short Squeeze.
Compare with volume
Volume shows activity; OI shows commitment that remains. See Volume.
Watch expiry
OI in a futures month falls towards expiry as positions are closed or rolled. See Futures Contract.
Worked examples
Example 1 — Counting open interest
CountingA new futures contract starts with OI 0. Trader A buys 5 from trader B (both new): OI 5. Trader C buys 3 from A, who is closing: OI 5. B buys back 2 from D, a new seller: OI 5. A sells 2 to B, who is closing: OI 3.
| Open interest after all trades | 3 contracts |
| Volume | 5 + 3 + 2 + 2 = 12 contracts |
Volume counts every trade; open interest counts what is still open.
Example 2 — Reading price and OI together
LeverageOver a week, a crypto perpetual rises 8% while open interest rises from $2.0 billion to $2.6 billion, and funding turns strongly positive.
| Price | +8% |
| Open interest | +30% |
| Reading | New leveraged longs building |
Fresh leverage fuels the move — and creates a pool of longs that can be forced out in a sharp drop. See Long Squeeze and Funding Rate.
Example 3 — A rise on falling open interest
CoveringA heavily shorted future rises 6% in two days while open interest falls 15%.
| Price | +6% |
| Open interest | −15% |
| Reading | Shorts covering rather than new buyers |
Rallies driven by short covering can fade once the covering is done.
Common readings of price and open interest
| Aspect | Usual interpretation |
|---|---|
| Price up, OI up | New longs entering; trend supported |
| Price up, OI down | Shorts covering; rally may lack new buyers |
| Price down, OI up | New shorts entering; decline supported |
| Price down, OI down | Longs liquidating; selling may be exhausting |
Why traders watch open interest
Confirming trends
Rising OI with price suggests fresh commitment behind the move. See Trend.
Spotting crowded positioning
Very high OI with extreme funding signals heavy leverage on one side.
Liquidity in a contract
Higher OI usually means more participants and easier trading. See Liquidity.
Commitments of Traders
The CFTC’s weekly report breaks open interest down by trader type. See Commitments of Traders Report.
Advantages and disadvantages
Advantages
- Shows whether money is entering or leaving a market.
- Adds context to price and volume.
- Widely published for futures, options and crypto derivatives.
Disadvantages
- Interpretations are rules of thumb, not certainties.
- Does not show which side is “right”, only that positions exist.
- Exchange-traded futures report OI daily; intraday changes may be hidden.
- Crypto OI is spread across many exchanges with different reporting.
Going deeper
Read as far as you need. Each level builds on the one before it.
Every contract has two sides
Beginner
Open interest counts contracts, not people. One open contract means one long and one short — so OI never tells you there are “more buyers than sellers”.
Options open interest
Intermediate
For options, open interest by strike shows where large positions sit. Strikes with very high OI can attract attention around expiry, as hedging by option dealers changes. See Options.
OI in crypto
Advanced
Crypto derivatives OI is often quoted in dollars, so it rises with price even if contract numbers do not. Compare OI in coins or contracts where possible, and aggregate across major exchanges.
Common mistakes
Confusing OI with volume
Volume is traded contracts; OI is open contracts.
Reading OI as buyers vs. sellers
Every open contract has both.
Ignoring dollar-denominated effects
Dollar OI rises with price alone.
Using one exchange’s data
In crypto, aggregate where you can.
Check your understanding
Test yourself before moving on. Each answer comes with an explanation.
Key points to remember
- Open interest counts contracts still open; volume counts contracts traded.
- OI rises when both sides open new positions and falls when both close.
- Price and OI together hint at whether moves are new money or covering.
- High OI with extreme funding signals crowded leverage.
- Interpretations are tendencies, not rules.
Frequently asked questions
What is the difference between open interest and volume?
Is high open interest bullish?
Do stocks have open interest?
Further learning
- Futures Contract
The contracts open interest is usually measured on.
- Funding Rate
Read with OI to judge crowding in crypto.
- Volume
The difference between traded and open contracts.
- Short Squeeze
What falling OI in a rally may indicate.
Sources
This article is written in our own words. The sources below support the specific facts, rules and figures marked with a number in the text. Links open the original publisher’s page.
- CME Group. Open Interest (opens in a new tab) Checked .
- U.S. Commodity Futures Trading Commission. CFTC Glossary (opens in a new tab) Checked .
Educational content, not financial advice. Examples use hypothetical prices and simplified costs; actual fees, margin rules and regulations vary by broker, market and country. We are not affiliated with any publisher linked above. Last reviewed . Report an error or request a source credit.