What Is Open Interest?

How Open Interest Works

Open interest increases when a new buyer and a new seller both open fresh positions, creating a new contract. It decreases when an existing long and an existing short both close their positions, eliminating a contract. Importantly, if an existing long sells to a new long, open interest stays the same—one position was closed, but another was opened.

Here is how different trade scenarios affect open interest:

Open interest is always measured in contracts or notional value (e.g., USD). Some platforms report OI in the number of contracts, while others report it in dollar terms to make cross-asset comparisons easier.

Open Interest vs Trading Volume

Open interest and trading volume are related but measure fundamentally different things:

• Trading volume counts every contract that changes hands during a given period. A single contract could be traded back and forth ten times in a day, contributing ten units of volume.
• Open interest counts how many contracts are currently active. It only changes when net new positions are created or destroyed.

Volume tells you about market activity and liquidity at a given moment. Open interest tells you about market commitment—how much capital is currently deployed in open positions.

A market with high volume but declining open interest suggests traders are closing positions (de-leveraging). A market with rising volume and rising open interest suggests new capital is entering and new positions are being established.

Why Open Interest Matters for Traders

Open interest provides several valuable signals for traders:

• Trend confirmation – Rising OI during a price uptrend suggests new longs are being opened, confirming bullish conviction. Rising OI during a downtrend confirms bearish conviction.
• Trend exhaustion – Falling OI during a price trend suggests existing positions are being closed rather than new ones being opened. This can precede a trend reversal.
• Liquidation risk assessment – High open interest relative to market capitalization indicates heavy leverage. Sudden price moves can trigger cascading liquidations, amplifying volatility.
• Support and resistance – Large concentrations of open interest at specific price levels can act as magnets or barriers, as liquidations and stop-losses cluster around those levels.

Many professional traders use OI data alongside funding rates, liquidation maps, and order flow to build a comprehensive picture of market positioning.

Open Interest Across Exchanges

Aggregate open interest across all exchanges is a macro-level indicator of total market leverage. Several data providers track open interest across centralized and decentralized venues:

• Centralized exchanges – Platforms like Binance, Bybit, and OKX typically hold the largest share of perpetual futures OI, often exceeding tens of billions of dollars for BTC alone.
• Decentralized exchanges – Protocols like Hyperliquid and dYdX have seen growing OI as on-chain derivatives adoption increases. Hyperliquid's OI regularly exceeds billions of dollars.

Comparing OI distribution across exchanges reveals where the marginal trader is most active. Shifts in OI concentration—for example, from centralized to decentralized venues—can signal structural changes in market participation.

Open Interest and Liquidations

Open interest and liquidations are closely linked. When open interest builds up rapidly—indicating heavy leveraged positioning—the market becomes vulnerable to liquidation cascades:

• A sudden price move against the dominant position (e.g., a drop when OI is skewed long) forces margin calls and liquidations.
• Liquidations are essentially forced market orders that further push the price in the same direction, triggering more liquidations.
• This cascade rapidly reduces open interest as positions are forcibly closed, often resulting in sharp price spikes or crashes.

Monitoring the rate of OI buildup relative to price movement helps traders assess whether a market is becoming overleveraged and prone to a liquidation event. A sharp rise in OI without a corresponding price move is particularly concerning, as it suggests leveraged positions are being opened with thin margins.

Open Interest for Exchange Operators

For teams operating whitelabel or branded exchanges, open interest is a key business metric:

• Revenue proxy – Higher OI generally correlates with higher trading volume, which drives fee revenue. Exchanges earn fees when positions are opened and closed, so active OI turnover is more valuable than stagnant OI.
• Risk monitoring – Operators need to monitor OI concentration to understand their platform's risk exposure. A single large position can represent systemic risk if it is liquidated.
• Product development – OI data helps operators decide which markets to list. High OI on external venues for a particular asset suggests demand that can be captured by offering that market.

Infrastructure platforms like perps.studio enable operators to access real-time OI data from underlying venues, allowing them to build analytics dashboards and risk monitoring tools for their users.