What is open interest in crypto? Explained with Hyperliquid data
Open interest is the total size of trades still open. How it differs from volume, the four price and open interest mixes, and how often each happened.
Open interest is the total size of trades that are still open. Volume counts every trade, but open interest only changes when positions are opened or closed. In our test of 169 smaller coins on Hyperliquid, from June 23 to September 24, 2026, all four mixes of price and open interest were common: from 21.17% of 10,712 coin-days (price down, open interest up) to 28.49% (both down). Past cases, not a forecast.
For what came next after rising open interest and a falling price, see Rising open interest and falling price: what came next?.
What is open interest?
A perp is a futures contract that never expires (see what is a perpetual future). A trader can open a long, which gains when price rises, or a short, which gains when price falls. A position stays open until the trader closes it, or until the exchange does it for them. Open interest is the total size of all positions that are open right now.
Every trade has two sides. For one long to exist, someone else holds the matching short. So open interest counts each pair once, not twice.
Open interest rises when two traders both open new positions. It falls when two traders both close positions. It does not change when a new trader takes over a position from one who is leaving.
How is open interest different from volume?
Volume is how much was traded. Open interest is how much is left open. Here is a small example in coins:
- Anna buys 10 coins of a perp from Ben. Both open new positions. Volume is 10 and open interest is 10.
- Carl buys 4 coins from Anna. Anna closes part of her long and Carl opens one. Volume is now 14. Open interest is still 10.
- Anna sells her last 6 coins to Ben, who closes part of his short. Volume is now 20. Open interest falls to 4.
A busy day can have huge volume and no change in open interest, so traders look at both.
What are the four price and open interest combinations?
Look at one day and ask two questions. Did price rise or fall? Did open interest rise or fall? That makes four combinations. The common readings are:
- Price up, open interest up: new trades opened while price rose. Many people read it as new money joining the rise.
- Price up, open interest down: trades closed while price rose. A common reading is that shorts were being closed out.
- Price down, open interest up: new trades opened while price fell. A common reading is that new shorts, or longs added too early, were piling in.
- Price down, open interest down: trades closed while price fell. A common reading is that traders were leaving, or were forced out.
These are stories. Do the numbers agree?
How often did each combination happen?
We looked at 169 Hyperliquid coins from June 23 to September 24, 2026, which is 94 days. A coin-day is one coin on one UTC day, and we had 10,712 of them. BTC, ETH, SOL, HYPE, XRP and DOGE are not in the records we used, so this describes smaller listings, many of them thinly traded.
For each coin-day, we added up the net change in open interest across the day, and measured the day's price move from close to close.
| Combination | Coin-days | Share of all | Coin-days with a next day | Up the next day | Middle next-day move |
|---|---|---|---|---|---|
| Price up, open interest up | 2,911 | 27.18% | 2,568 | 48.36% | −0.17% |
| Price up, open interest down | 2,417 | 22.56% | 2,101 | 49.02% | −0.08% |
| Price down, open interest up | 2,268 | 21.17% | 1,985 | 51.44% | +0.12% |
| Price down, open interest down | 3,052 | 28.49% | 2,670 | 52.88% | +0.21% |
| All coin-days | 10,712 | 100% | 9,382 | 50.43% | +0.05% |
The "middle" move is the median: sort all the results and take the one in the middle. A tiny number of days had almost no change in open interest. We left them out of the table because there are too few to read.
Did any combination predict the next day?
No. The next-day up share ranged from 48.36% to 52.88%, around a base of 50.43%. With only 94 days, the typical error on each share is about 4 points either way. We checked each one against the base, allowing for the fact that coins move together on the same day. None came near the level where we would call it a difference. Counting each coin equally, instead of each coin-day, gave much the same shares, from 48.17% to 53.04%.
Notice the pattern: after the two combinations where price fell, the next day was slightly better, and after the two where price rose, slightly worse. That could be a bounce, or it could be luck. Ninety-four days of one market mood cannot tell the two apart. For a closer look at the most-asked box, see rising open interest with falling price.
Which side got forced out?
Each of these days also had forced closings, called liquidations. A liquidation is when an exchange closes a trade because the trader's money ran out. This table shows the average forced closing per coin-day, on the same day as the price move.
| Combination | Longs forced out | Shorts forced out |
|---|---|---|
| Price up, open interest up | $17,518 | $57,003 |
| Price up, open interest down | $9,105 | $27,815 |
| Price down, open interest up | $22,486 | $4,157 |
| Price down, open interest down | $55,828 | $5,051 |
On days when price rose, more shorts were forced out. On days when price fell, more longs were. That is how the numbers should work, so it is a useful check that the data is sound.
Most coin-days had no liquidations at all, so the median in every group was $0. Between 39% and 48% of coin-days in each group had any. A few big days pull the averages up. For the biggest cases, see what happened after liquidation cascades.
What does this data not show?
It does not show that any combination is a reason to buy or sell. It does not cover Bitcoin, Ethereum, Solana, HYPE, XRP or DOGE on Hyperliquid, or any other exchange.
It covers about 13 weeks in one market mood. Coins and days are not independent, because on a day the whole market falls, many coins land in the same box. The real sample is closer to 94 days than to 10,712.
Open interest here is the daily sum of dollars opened minus dollars closed, valued at the trade price. It is the change, not the level. A price move on its own does not change it.
How we measured this
We used per-minute Hyperliquid records for 169 coins from June 23 to September 24, 2026, and each coin's daily closing price. A day counted only when it had a full close and the day before had one too. For each coin and UTC day we added up the minute-by-minute change in open interest in dollars, and took the price change from one close to the next. A day was "flat" if open interest barely moved, compared with the coin's own recent typical change.
The outcome is the next day's price change from close to close. We report counts, the share of up days and the median. Margins of error treat each calendar day as one unit, because coins move together. We tested no trading rule, so there are no fees.
Try this in Comparand
Ask your connected AI agent: "Call hl_coverage first, then show the net change in open interest for a Hyperliquid coin I name, hour by hour, over one day."
- hl_coverage lists the archive days, the coins and which days are complete. It is free and has no arguments, so call it first.
- hl_oi returns, for each bar, the dollars opened, the dollars closed and the net. It does not return the open interest level. The default bar is one minute. On a plan, it is unlimited under fair use. On pay as you go it costs $0.005 per call.
Then ask: "Show the per-minute labels for the same coin over one hour, with only the fields I choose."
- hl_labels returns per-minute labels for one coin between a start and end time in the archive. The optional fields setting lets you keep only the columns you need. Our daily sums came from per-minute records in this archive.
- Each answer says which days it came from and what the call cost.
To check price on the same day, ask for the coin's bars with hl_bars. You can try 3 coins free, see pricing, or read the tool docs. Funding is another measure of crowded positions; see Hyperliquid funding rates.
The short version
- Open interest is the total size of trades still open. Volume is everything traded.
- On Hyperliquid, open interest rose while price fell on 2,268 of 10,712 coin-days (21.17%).
- The next day was up 51.44% of the time after those days, against 50.43% for all coin-days.
- All four price and open interest combinations had next-day up shares between 48.36% and 52.88%.
- Forced closings followed price: shorts on up days, longs on down days. These are past cases, not a forecast.
Questions people ask
What is open interest in crypto?
Open interest is the total size of trades that are still open and have not been closed. On a perp exchange such as Hyperliquid, it counts positions that traders still hold. It is usually shown in dollars or in coins.
Is open interest the same as volume?
No. Volume counts every trade that happened, including trades that close old positions. Open interest counts only what is still open at a given moment. One trader can add to volume many times without changing open interest at all.
What does rising open interest with falling price mean?
It means more new trades were opened than closed while price fell. On Hyperliquid this happened on 2,268 of 10,712 coin-days (21.17%) from June 23 to September 24, 2026. The next day, price was up 51.44% of the time, against 50.43% across all coin-days.
Does falling open interest mean traders are leaving?
It means more trades were closed than opened, either by traders choosing to exit or by an exchange closing positions after a trader's money ran out. It does not say which of the two happened.
Does Comparand's hl_oi tool show total open interest?
No. It shows the change in open interest in each bar, split into dollars opened, dollars closed and net. It does not return the open interest level.