Open Interest: What It Means and How to Read It

Open interest is the total number of futures, perpetual or options contracts that are still open, meaning they have been opened and not yet closed, settled or liquidated. It measures how much money is committed to a market right now, not how much has traded. Read alongside price, volume and the funding rate, open interest helps you judge whether a move is being built by new positions or driven by traders closing old ones.

This guide is part of our series on crypto derivatives and covers how to read open interest with price, volume and funding.

Quick answer: Open interest is the total number of derivative contracts (futures, perpetual swaps or options) that are open and not yet closed or settled. Open interest rises when a new buyer and a new seller open a position together, and falls when both sides close. Open interest measures committed positions, while trading volume measures how many contracts changed hands.

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What is open interest?

Open interest is the number of derivative contracts outstanding at a given moment. Every futures or perpetual contract has two sides, a long and a short, so one open contract means one trader is long and another is short. Open interest counts each contract once, not each side.

Exchanges publish open interest in contracts, in the underlying coin or in US dollars of notional value. The dollar figure moves with price even if nobody opens or closes anything. If 2,000 BTC of open interest is held when BTC is 60,000 USD, the notional open interest is 2,000 x 60,000 = 120 million USD. If price rises 10% to 66,000 USD and no position changes, the same 2,000 BTC is now worth 132 million USD. When you compare open interest over time, check whether you are looking at a coin figure or a dollar figure.

Key facts about open interest

How does open interest change?

Open interest changes only when the number of open positions changes, which depends on whether each side of a trade is opening or closing.

A worked example over four days

Follow one small market from zero:

1. Day 1. Trader A buys 10 contracts from Trader B. Both are opening. Open interest goes from 0 to 10. Volume is 10.
2. Day 2. Trader C buys 5 contracts from Trader D. Both are opening. Open interest is 10 + 5 = 15. Volume is 5.
3. Day 3. Trader A sells 4 contracts to Trader E. A is closing part of a long, E is opening a new long. Open interest stays at 15. Volume is 4.
4. Day 4. Trader B buys 5 contracts from Trader C. B is closing part of a short, C is closing a long. Open interest is 15 minus 5 = 10. Volume is 5.

Over the four days, 24 contracts traded (10 + 5 + 4 + 5), but only 10 remain open. That gap is the whole difference between volume and open interest.

What is the difference between open interest and volume?

Volume counts how many contracts traded during a period, while open interest counts how many contracts are still open at the end of it. Volume resets every period; open interest carries over until positions close.

A market can have huge volume and flat open interest when day traders open and close within the same session, or modest volume and rising open interest when traders open positions and hold them. Tools such as volume profile show where trading happened, and open interest adds whether that trading left positions behind.

Is high open interest bullish?

High open interest is not bullish or bearish on its own, because every open long is matched by an open short. What matters is how open interest changes alongside price. The four combinations below are the standard way traders read it.

These are tendencies, not rules.

The chart shows all three stages in sequence. In the first part of the rally, price climbs while open interest climbs with it, marked as new longs: positions are being added as the trend develops. The last leg up comes with open interest falling, marked as short covering: price is still rising, but positions are shrinking, which means shorts buying back rather than new buyers arriving. When price then turns lower, open interest keeps falling, marked as longs exiting: the decline comes from traders closing positions, not from new shorts piling in.

Why the short-covering leg matters

A rally on falling open interest is often weaker than it looks: once shorts have bought back, that source of demand is gone. This is the mechanism behind many short squeezes: forced or panicked buying from shorts produces a sharp move that can reverse once the covering is done.

How does open interest relate to the funding rate?

Open interest shows how many positions are open, and the funding rate shows which side of a perpetual contract is more aggressive. Together, they indicate whether positioning is crowded. On a perpetual swap, funding is a periodic payment between longs and shorts, commonly every 8 hours, that keeps the contract price close to the spot index. Positive funding means longs pay shorts; negative funding means shorts pay longs. Intervals, formulas and caps vary by exchange.

The chart shows an 8-hour funding rate moving from 0.010% up to 0.031% over the first day and a half as longs crowd in, then dropping below zero to a low of minus 0.012% when shorts dominate, before returning near zero. If open interest were rising during the climb to 0.031%, the reading would be: many new positions opened, and the long side is paying more and more to hold them. That combination is what traders call crowded longs.

The cost is easy to calculate. Funding paid equals position notional x funding rate. On a 50,000 USD long at 0.031% per period, one payment is 50,000 x 0.00031 = 15.50 USD. Three payments a day at that rate is 46.50 USD, or about 0.09% of notional per day, paid whether or not price moves.

Crowded positioning and liquidations

When open interest is high and funding is strongly one-sided, a large share of traders hold the same leveraged bet. If price moves against them, the exchange closes positions that run out of margin, a process explained in our guide to liquidation in trading. Each forced close is a market order in the opposite direction, which pushes price further and can trigger the next batch of liquidations. You see this in the data as a sharp price move with a sudden drop in open interest. The exact price used to trigger liquidations is usually a mark price rather than the last traded price, and the rules differ by venue.

A practical routine for reading the three together:

1. Note the direction of price over your chosen window.
2. Check whether open interest rose or fell over the same window (in coin terms if possible).
3. Check whether funding is near zero, strongly positive or strongly negative.
4. If open interest is high and funding is extreme, treat the market as crowded and size down rather than adding to the crowded side.

How is open interest different in crypto versus stock options and futures?

Open interest works the same way everywhere, but reporting differs. On regulated futures venues such as CME, open interest is reported by the exchange, typically once a day after the session, and each contract has a fixed size and an expiry date. As expiry approaches, open interest in the front contract falls as traders close or roll positions into the next month.

In crypto, most open interest sits in perpetual futures, which have no expiry, so there is no roll cycle. Exchanges publish open interest continuously, and data providers aggregate it across venues. High leverage on many crypto venues means the same dollar of open interest can carry more liquidation risk.

Options open interest is counted per strike and expiry, separately for calls and puts. Traders look at where open interest clusters to see which strikes the market is positioned around. If you are new to options, our explainer on calls versus puts covers the basics.

What are the limits of open interest?

Open interest has three main limits that every trader should keep in mind:

• No direction. Every long has a short. Rising open interest means more positions, not more bulls.
• Dollar distortion. Notional open interest rises and falls with price even when no positions change. Use coin or contract figures for cleaner comparisons.
• Fragmented data. Crypto open interest is spread across many exchanges, and aggregated figures can differ by provider. One venue's spike may not reflect the whole market.

Open interest is context, not a trade signal. Broker disclosures and academic studies consistently find that most retail day traders lose money, and leveraged derivatives raise that risk. Open interest can help you avoid stepping into a crowded trade, but it does not replace a plan built on risk management.

Can AI help with reading open interest?

AI can help screen many markets for unusual open interest changes, flag rising open interest with extreme funding, and analyse your trade journal. It can also speed up backtesting of rules that combine price, open interest and funding.

AI does not remove risk. Open interest data is noisy and the same pattern can resolve either way, so any model output needs human judgement and a defined risk limit. Our guide to AI trading strategies covers where these tools help and where they fall short.

Using open interest in a prop trading evaluation

Velotrade, a multi-asset prop trading firm, offers simulated evaluations with crypto trading 24/7 across 100+ instruments. Open interest is context you read from public derivatives data. For price comparison, Velotrade's FAQ points traders to the matching KuCoin USDT perpetual symbols on TradingView.

A few rules shape how that context is useful inside an evaluation. Velotrade does not charge a variable funding rate. It charges a flat overnight rate of 0.05% of notional on crypto positions open at 00:30 UTC, every day including weekends, the same whether long or short, and crypto commission is 0.03% per side. The hard limits are the daily loss limit, which resets at 00:30 UTC from the higher of balance or equity (5% on CLASSIC 2-Step, 4% on CLASSIC 1-Step, 3% on PRO 1-Step), and the static maximum drawdown. Position size is limited only by the available leverage, which for BTC is 10x in the challenge and 5x when funded.

That makes open interest a filter rather than a trigger. In a crowded market, a sharp unwind can hit your daily loss limit in minutes, so sizing down or not trading is often the better choice. A profitable trade is not the same as a good trade, and staying out of a crowded move is part of trading well. There is no time limit on the evaluation, so there is no need to force a position.