Open Interest

Open interest (often abbreviated OI) is the total number of contracts currently open and not yet closed in a given contract market, or its converted total value. Note it measures a stock, not volume: volume is how many trades happened over a period, while OI is how many positions are still live right now. Every time a new buyer and a new seller open a fresh contract, OI goes up by one; when someone closes and a contract is offset, OI goes down by one. It measures the total scale of bets currently in play in the market.

From price alone, you can't tell whether a rally is driven by genuinely new money entering or just a few players wash-trading to fake strength. Open interest fills that gap: it lets you see whether capital is flowing in or out behind a price move. Rising OI means new positions are opening and new money is entering; falling OI means positions are closing and money is leaving. Combine OI with price direction and you can read whether a move is actually backed by money — a dimension of information you simply can't get from candlesticks alone.

OI is most useful read together with price. Price up with OI rising means new money supports the advance — a relatively healthy trend; price up but OI flat or falling may be short-covering with no fresh buying, a weaker rally. Price down with OI rising means new shorts are piling on, momentum behind the drop; price down but OI crashing usually means longs were heavily closed or liquidated, often near a capitulation bottom. Also, high OI signals crowded leverage and a fragile market, where an adverse move easily triggers cascading liquidations. People who read OI spot the truth of a trend, and market fragility, earlier.

First, build the habit of viewing OI alongside price — most market-data sites and exchanges show OI charts for free. Second, when you see OI spike to historic highs together with elevated funding, raise your guard: this means leverage is overcrowded and the market is in a fragile state prone to cascading liquidations — not the time to chase with a heavy position. Third, use OI to verify breakouts: if price breaks a key level with OI expanding, it's more credible; if OI doesn't follow, beware a fake breakout. Fourth, don't treat OI as a standalone buy/sell signal — it's a tool to help read capital flow, to be combined with price, funding, and volume.