Open interest in crypto: what it is and how to read it as a trader

Open interest in crypto: what it is and how to read it as a trader

Open interest (OI) is one of the most useful metrics in the derivatives market. It shows how much money is currently sitting in open futures positions.

In this guide, we cover how OI is calculated, how it differs from volume and how to read it together with price and funding.

What open interest is in simple terms

Open interest is the total number of futures contracts that have been opened and not yet closed. Every position has two sides: a buyer who is long and a seller who is short.

When a new long meets a new short, OI goes up. When both sides close their positions, OI goes down.

If one trader simply hands a position over to another, open interest does not change. Only the owner of the contract has changed.

Exchanges usually show OI in contracts, in coins or in dollars. The dollar value is the most convenient for comparing different venues.

How open interest differs from trading volume

Volume counts all trades over a period, including both openings and closings. OI shows what remains - how many positions are on the market right now.

Volume is like the flow of cars through an intersection over a day. Open interest is like the number of cars parked in a lot at a given moment.

From what we see, high volume with flat OI often means traders are rotating from one position to another. Very little new money is entering the market.

How to read price, open interest and funding together

On its own, OI says little. It starts to make sense when you read it alongside price and the funding rate on perpetual futures.

The first scenario is the most common in a strong trend. If funding climbs high at the same time, the market becomes overheated: too many positions are on one side.

The second scenario is often called a short squeeze. The rally is driven by forced short closing, so it tends to be fast but short-lived.

We believe the most informative signal is divergence. If price is almost flat while OI and funding are rising, positions are building up, and the market is setting up for a sharp move in one direction or the other.

How open interest relates to liquidations

The more leveraged positions are open, the more fuel there is for liquidations. High OI is not dangerous in itself, but during a sharp price move it turns into a cascade of forced closures.

After large liquidations, OI usually drops sharply. The market flushes out leverage, and funding returns closer to zero.

In our view, a useful habit is to compare OI not with yesterday but with its level a week or a month ago. That makes it easier to notice when there is unusually high leverage in the market.

How an arbitrage trader can use open interest

An arbitrage trader usually does not trade direction, but OI helps with timing. This is especially true for funding trades, where you open spot against a perp, or a perp against a perp on different exchanges.

• High OI and high funding: the rate pays generously, but the market is overheated, and a sharp pullback can wipe it out quickly.
• OI on one exchange is growing faster than on others: funding and the perp price get skewed there more often.
• OI dropped sharply after liquidations: funding will likely normalize soon, and the trade is worth recalculating.
• OI is low and stable: rates are modest but predictable.

A hypothetical example

Take a textbook example with rounded numbers. OI on the coin X perp on exchange A grew from $40 million to $64 million over a week, while funding holds at around 0.05% per eight-hour period.

On exchange B, funding on the same perp is around 0.01%, and OI has barely changed. The arbitrage trader opens a perp short on exchange A and a long on exchange B for the same amount to collect the rate difference without betting on direction.

The difference is 0.04% per period, or about 0.12% per day with three payments. On a $10,000 position, that is roughly $12 per day before fees.

But OI growing more than one and a half times in a week signals overheating. If liquidations start, funding on exchange A can drop quickly, and the trade will stop earning the difference before it covers the entry and exit fees.

Where to check open interest

Exchanges publish OI on their contract pages, and derivatives aggregators combine it across venues. For arbitrage, it is more useful to see OI and funding across several exchanges at once than on just one.

The most convenient approach is to watch the trend over several days. A single number at a single moment tells you almost nothing about whether leverage is building up.

Our tools

Funding skews often start on a single exchange, so it helps to see rates across all venues at once. Our arbitrage screener keeps dozens of venues in one window, refreshes quotes every second and shows each gap together with the volume actually behind it. The spread calculator helps you check what survives fees, network costs and slippage at your size. The bot is fully manual. It never connects to your exchange API keys.

To test the tools on a live market, ArbitrageScanner offers one day of free access to the whole ecosystem.

FAQ (Frequently Asked Questions)

1. What is open interest in crypto?

It is the total number of futures contracts that are open and not yet closed. The metric reflects how much money is currently in positions in the derivatives market.

2. How does open interest differ from volume?

Volume counts all trades over a period. Open interest shows how many positions remain open at a given moment.

3. What does rising open interest with rising price mean?

Usually it is a sign that new longs are entering the market. If funding also rises sharply, the market may be overheated.

4. Is falling open interest good or bad?

Neither, on its own. Falling OI means positions are being closed, either voluntarily or through liquidations, and there is less leverage in the market.

5. Where can I check open interest on futures?

On exchange contract pages and in derivatives aggregators. For arbitrage, it is more convenient to compare OI and funding across several venues at once.

6. How does open interest help with funding rate arbitrage?

It tells you how overheated the market is. High OI combined with high funding gives a generous rate but raises the risk of a sharp pullback.

Conclusion

Open interest shows how much money is currently tied up in futures positions. It only makes sense to read it together with price and funding.

For an arbitrage trader, OI helps gauge overheating and pick the right moment for a funding trade. A high rate in an overheated market looks attractive but rarely lasts.

IMPORTANT! We are software developers. We do not give recommendations or promises of earnings and we do not advise you to invest your money anywhere. Our software is fully manual, all your money stays under your own control. We show examples of how our clients have earned on arbitrage in the past, but we do not advise repeating those actions one to one. Your earnings depend solely on your own actions and on market factors.