Open interest
Open interest is the total number, or dollar value, of futures and perpetual contracts that are still open. It rises when new positions are opened and falls when positions are closed, so it measures how much leverage is in the market rather than how much is traded.
Open interest now
16:48 UTC| Perpetual | Open interest | 1 hour | 4 hours |
|---|---|---|---|
| Bitcoin | $3.45B | ▼ −0.53% | ▼ −0.35% |
| Ethereum | $2.64B | ▼ −0.42% | ▲ +0.50% |
Hyperliquid perpetuals only, in US dollars at the current mark price.
How it works
Every futures contract has a buyer and a seller, a long and a short. Open interest counts those pairs once. It changes only when a trade opens or closes positions, not every time a contract changes hands:
- Both sides open new positions: open interest rises.
- One side opens, the other closes: an existing position just passes to someone new, and open interest is unchanged.
- Both sides close: open interest falls.
That makes open interest different from volume. Volume counts every trade. A market can trade billions in a day with flat open interest if traders are only passing positions back and forth.
Open interest is quoted either in coins (contracts) or in dollars. The dollar figure is the coin figure times price, so it rises when price rises even if nobody opens a new position. Liquidations reduce open interest too: a liquidated long is a closed position.
A worked example
Four trades on a BTC perpetual, with BTC at $100,000:
| Trade | What happens | Open interest |
|---|---|---|
| Alice buys 1 BTC from Bob; both open | New long and new short | 1 BTC |
| Carol buys 1 BTC from Dan; both open | Another pair | 2 BTC |
| Erin buys 1 BTC from Alice, who closes her long | Long passes from Alice to Erin | 2 BTC |
| Bob buys 1 BTC back from Erin; both close | One pair disappears | 1 BTC |
Four trades, 4 BTC of volume, and open interest ends at 1 BTC.
Now the dollar effect. Open interest on a market is 30,000 BTC, or $3.0 billion at $100,000. Over a day price rises 4% to $104,000 and dollar open interest rises 9% to $3.27 billion. In coins that is $3.27 billion / $104,000 = 31,442 BTC, an increase of 4.8%. Roughly half of the headline 9% came from price, the other half from new positions.
What it tells you
The box above shows open interest on Hyperliquid for BTC and ETH in dollars, with the change over the last hour and the last four hours. Because it is in dollars, compare the change with the price change over the same window before reading anything into it.
Read together with price, open interest gives a rough picture of who is acting:
| Price | Open interest | Usual reading |
|---|---|---|
| Up | Up | New positions are driving the move, typically new longs |
| Up | Down | Shorts closing, a short squeeze or short covering |
| Down | Up | New positions pressing the move, typically new shorts |
| Down | Down | Longs closing or being liquidated |
This is a heuristic. Every new long has a new short on the other side, so the table describes which side is the aggressor, not which side exists. Funding helps settle it: rising open interest with strongly positive funding points to longs paying up to get in.
High open interest on its own is neutral. It measures how much leveraged exposure is stored in the market, and therefore how much forced buying or selling could be released if price moves against it.
When it matters most
Open interest matters most when it has climbed quickly alongside price and funding is stretched. Many of those positions were opened near the same levels, so their liquidation prices sit close together. That is the setup for a liquidation cascade. A sharp drop in open interest over minutes, together with a large price move, is the footprint of one.
It also matters relative to liquidity. The same open interest is a bigger risk in a thin order book on a weekend than in a deep one during US trading hours.
After a flush, low open interest means less leverage is left to force out. Moves from there tend to be driven more by spot buyers and sellers.
Common misconceptions
"Rising open interest is bullish." It means positions are being added on both sides. Whether that supports the move depends on which side is paying, which funding and price show better than open interest alone.
"Open interest is the same as volume." Volume counts trades; open interest counts positions still open. High volume with flat open interest means positions are changing hands, not being added.
"Dollar open interest at a record means record leverage." If price is also at a record, the dollar figure is inflated by price. Compare in coins, or compare the change with the price change.
"High open interest means a crash is coming." It raises fragility without setting a time or a direction. Open interest can stay high for weeks, and the release can be a short squeeze as easily as a long flush.