Learn / Risk & Position Sizing
What open interest tells you
Open interest is the number of derivative contracts currently held open. It rises when a new position is created and falls when one is closed — which makes it a measure of positioning, not activity.
Volume tells you how much changed hands. Open interest tells you how much is still out there, and the distinction is where its usefulness comes from.
How it moves
Every contract has a long and a short. What happens to open interest depends on whether each side is opening or closing:
| Buyer | Seller | Open interest |
|---|---|---|
| Opening long | Opening short | Rises — new position created |
| Opening long | Closing long | Unchanged — position transferred |
| Closing short | Opening short | Unchanged |
| Closing short | Closing long | Falls — position extinguished |
So high volume with flat open interest means positions changing hands. High volume with rising open interest means new exposure being created.
The four combinations
Read alongside price, open interest distinguishes situations that look identical on a chart:
Price up, OI up — new longs entering. The move is backed by fresh positioning, and there is now more leveraged exposure that has to be defended.
Price up, OI down — shorts closing. A move driven by covering rather than conviction, and it exhausts when the shorts are gone.
Price down, OI up — new shorts entering.
Price down, OI down — longs closing or being liquidated. This is the signature of forced selling, and it is what liquidation cascades look like in the data.
None of this is a trade signal. It is context about what a move is made of, and using it as a signal is a reliable way to be early.
What it is actually good for
Judging how much fuel is in the market. Rising open interest alongside rising price means more leveraged longs, which means more positions that get liquidated if price reverses. Combined with funding rates — which tell you which side is paying — it describes where the crowd is and how large it is.
That is not predictive. It is a reason to be more careful with size and stop placement than usual.
Confirming that a move is exhausting. A rally on falling open interest is covering, and covering stops when the shorts are out.
Assessing an instrument’s real activity. Open interest relative to volume says something about whether an instrument is genuinely traded or just churned.
What it is not
Not a direction. Every contract has both sides, so open interest is symmetric by construction. “Open interest is rising” says nothing about who is right.
Not sentiment. It measures positions, not opinions, and a large position can be a hedge.
Not comparable across venues without care — contract sizes and conventions differ, and quoting a figure in contracts rather than notional makes venues incomparable.
Not available for spot. Open interest is a derivatives concept. Spot has no open positions to count, which is one of the real differences between perpetuals and spot.
Reading it with funding
The pair is more informative than either alone:
- Rising OI + persistently positive funding — a growing, crowded long side paying to stay. Maximum fuel for a downside cascade.
- Rising OI + negative funding — a growing short side paying to stay. Fuel for a squeeze.
- Falling OI + extreme funding — positioning unwinding. The crowd is leaving.
Again: context, not signals. Crowded conditions persist far longer than positions can, and trading against a crowd on the basis of it being crowded is how people are early and stopped out.
Practical use
Where this actually changes behaviour:
Size smaller when positioning is extreme. Not because you know what happens, but because when a move comes it will be larger — thin books plus forced flow means slippage is worse and stops fill further away.
Place stops with more room in those conditions, accepting the smaller position that implies — see why tight stops can cost more.
Reduce leverage so a gap does not reach liquidation before your stop — leverage and stop-loss table.
All three are adjustments to risk, which is the only thing this information can honestly be used for.
FAQ
What is the difference between open interest and volume?
Volume counts contracts traded over a period; open interest counts contracts currently held open. High volume with flat open interest means positions changing hands between traders. High volume with rising open interest means new exposure being created.
Does rising open interest mean price will go up?
No. Every contract has a long and a short, so open interest is symmetric and carries no directional information. What it tells you is how much leveraged positioning exists — which matters for how violent a reversal could be, not for which way price goes.
How do I use open interest with funding rates?
Together they describe where the crowd is and how big it is. Rising open interest with persistently positive funding means a growing long side paying to hold, which is the configuration with the most fuel for a downside cascade. Use it to adjust size and stop placement, not to time entries.
Is open interest available for spot markets?
No — it is a derivatives concept, counting open contracts. Spot trades settle immediately and leave no open position to count. This is one of the substantive differences between trading spot and trading perpetuals.