Open Interest (OI) in Forex
A clear definition of Open Interest (OI), with practical context for reading markets and making better trading decisions.
Definition
Open interest (OI) is the number of derivative contracts - such as futures or options - that remain outstanding and have not yet been closed, exercised, expired, or otherwise settled.
It measures existing contractual participation, not simply how many contracts traded today.
Open Interest vs. Volume
Volume counts how many contracts change hands during a period.
Open interest counts how many contracts remain open after those transactions.
A market can therefore have high trading volume without an equally large increase in open interest, because some trades may close existing positions rather than create new contracts.
What Open Interest Can Tell You
Changes in OI can help show whether participation in a derivatives market is expanding or contracting.
However, every derivative contract has both a long side and a short side. A high OI number by itself is therefore not automatically bullish or bearish.
Use It With Price Context
OI is most useful when interpreted alongside price, volume, contract specifications, and the relevant market structure.
For Level 3, treat it as supporting information. Do not replace the chart read with a single OI number.
Key Takeaway
Open interest measures outstanding derivative contracts; it does not tell you by itself whether buyers or sellers will win next.
Practical forex example
Why Open Interest (OI) matters
Understanding Open Interest (OI) helps traders interpret market information, plan decisions, and manage risk with more context.
Related forex terms
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