COT and Open Interest: Two Datasets Behind Every Futures Market
Open interest and the Commitments of Traders report are the two public datasets that shape how futures markets are described. A short note on how they complement each other.
pen interest and the Commitments of Traders report are the two public datasets that almost every serious description of a futures market is built on. They are easy to confuse — both deal with positions held in contracts — but they answer different questions, and they are published on very different timetables.
Open interest, briefly
Open interest is the total number of futures contracts that exist for a given market at the end of a trading day. It is published daily by the exchanges and it is available the same day. It tells you how much capital is committed to the market at a given moment, regardless of who is holding it.
Volume and open interest are often confused. Volume counts how many contracts changed hands during the session — a noisy, high-frequency number. Open interest counts how many positions survived the session — a slower, cleaner measure of market engagement.
COT, briefly
The COT report takes the same total open interest that the exchange reports and breaks it down by type of trader — who is holding those positions and on which side of the market. It is published once a week, on Friday, and reflects positions as of the previous Tuesday close. The report does not tell you anything the exchange is hiding; it tells you things the exchange never publishes at all, because the exchange does not organise its own data by trader category.
Why observers look at both
Open interest answers a quantity question: is money flowing into this market or out of it? COT answers a composition question: whose money is it? Neither alone is enough to form a complete picture, which is why most experienced futures commentary refers to both datasets in the same breath. A rally on rising open interest looks one way; the same rally looks quite different when the COT report shows it was driven by short-covering rather than new speculative buying.
Both datasets are public. Both are free. The work is in building the habit of checking them — and in knowing which question you are trying to answer before you open the file.
