Open interest

Imagine Petra opening a buying position in futures: a contract whose result depends on a future price. Her long position has a matching short position. For an ordinary linear futures contract, a long benefits from a rise in the contract’s price and a short from a fall, before costs. Our small market has 7 outstanding contracts: 7 long commitments match 7 short commitments. Open interest is 7, not 14. Petra can hold several contracts herself, so the contract count cannot tell us how many traders there are. [1] [3]

If both buyer and seller open a new position of 1 contract, OI rises by 1. If Petra sells to close her long while the buyer closes a short, OI falls by 1. If a new long holder buys instead, they simply replace Petra and the count stays unchanged. Closing does not require finding the original trading partner: exchange clearing allows positions to be offset through an opposite trade. What matters is whether each side is opening or closing, not merely whether the transaction is called a purchase. [5]

Start a separate example from zero. Trades create 2 contracts. Petra then sells to close 1 long, which a new buyer opens instead. Finally, another trade closes 1 long and a matching short. Total trading volume for the sequence is 4 contracts, while final OI is 1. Every trade contributed to volume, including the one that created no additional contract. Volume describes activity over a period; OI describes the position at a particular moment. Reading a chart requires that distinction and the time of measurement. [1] [5]

Petra compares CME’s standard Bitcoin futures, symbol BTC, with Micro Bitcoin futures, symbol MBT. The first represents 5 BTC per contract; the second, 0.1 BTC. This is the multiplier: the amount of the underlying asset represented by a contract. In our example, 100 standard contracts represent 500 BTC, while 100 micro contracts represent only 10 BTC. Adding them as 200 contracts counts units without making the exposures comparable. We must convert the units first. It does not mean that many bitcoins sit in an account: these contracts settle in cash. [2]

Keep the same notional exposure of 500 BTC in our example: the contractual quantity used to calculate value. At a conversion price of 60,000 USD per BTC, it is worth 30,000,000 USD. Revalue it at 66,000 USD and the display reads 33,000,000 USD. The contract count has not changed; only the conversion price has. This dollar value is neither the margin posted nor proof of a new deposit. We therefore check whether a data provider reports contracts, BTC or USD, and which price it uses. These numbers illustrate the calculation; they are not live quotations. [1] [2]

Aggregate long obligations equal aggregate shorts. Rising OI therefore does not mean that bullish positions have outnumbered bearish ones. A futures seller may also own Bitcoin and be protecting its value; the short need not be a standalone bet on a fall. We can compare longs and shorts within a particular group, but that requires more detailed data. OI does not show margin, the collateral supporting a position. Without that and other commitments, we cannot infer leverage—the position’s size relative to the funds backing it—or the risk of the entire portfolio. [3]

Petra may want to stay in the market when her futures contract is about to expire. She closes the nearer expiry and opens a later one, a process called rolling. Looking at OI by expiry helps: a decline in the expiring contract need not mean traders are leaving the market. A calendar spread combines opposing positions in different expiries. Their overlap can increase gross counts without an equal increase in exposure to the overall price direction; risk nevertheless remains. When combining data, we must not count the same market twice through different reports. [2] [3]

The US derivatives regulator CFTC publishes Commitments of Traders, or COT, reports showing positions held by groups of traders. They normally appear on Friday using Tuesday’s positions; holidays and schedule changes can delay publication. Distinguish observation from publication. The futures-only report covers futures; the combined report adds options converted to futures equivalents using their price sensitivity, called delta. It is not a simple addition of option counts. The reports do not cover every crypto exchange, and a trader’s classification does not reveal the purpose of every trade. Petra gains context, not a live map of the whole market or a price forecast. [3] [4]