01
The idea
Open interest is the number of contracts outstanding. Price tells you which way the market moved; the change in open interest tells you whether new positions were opened or existing ones closed. Together they classify the move.
02
The four patterns
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Long buildup: price up, open interest up. New buying is entering.
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Short buildup: price down, open interest up. New selling is entering.
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Short covering: price up, open interest down. Existing shorts are closing.
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Long unwinding: price down, open interest down. Existing longs are closing.
03
Futures versus options
The four labels fit futures directly because each contract has one long and one short. For options, a rise in open interest at a strike does not say whether buyers or writers opened it, and the same strike can hold both. Read options open interest changes together with price, implied volatility and the strike's position relative to spot, and treat the classification as an inference.
04
Limits
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Open interest is reported with a delay, and end-of-day changes can differ from intraday impressions.
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A rollover between expiries can look like unwinding in one contract and buildup in the next.
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The labels describe what happened, not what happens next.
05
In the Arkenwell terminal
Futures buildup classes appear in the screener filters, and the unusual activity view labels contracts with the same four intent classes alongside volume and open interest surge measures.
06
Frequently asked questions
What is long buildup?
Long buildup is a rise in price together with a rise in open interest, indicating new long positions are being opened.
What is the difference between short covering and long buildup?
Both have rising prices. In long buildup open interest rises (new positions); in short covering it falls (positions closing).
Does rising open interest at a put strike mean support?
Not by itself. Open interest does not show whether it was bought or written, so it must be read with price and volatility.
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