Funding Rates and Perpetual Futures
Perpetual futures are the dominant crypto derivative and have no equivalent in traditional markets. They track an underlying with no expiry date, so a position can be held indefinitely.
That raises an obvious question: without expiry, what forces the contract price toward spot? In a normal future, convergence at delivery does the work. A perpetual has no delivery.
Funding
The answer is a periodic payment between longs and shorts, typically every eight hours.
Perp above spot (more demand to be long): funding is positive, and longs pay shorts. Holding a long becomes expensive, which discourages it and pulls the price down.
Perp below spot: funding is negative, and shorts pay longs.
The mechanism replaces convergence with a continuous economic incentive. It is an elegant piece of design and it makes the instrument's cost of carry explicit and observable, which is unusual.
Push the premium through zero and the payment reverses. Then read the annualised figure: a rate that looks like a rounding error three times a day is a serious cost of carry over a year, which is the number that decides whether a position is worth holding at all.
Funding is what anchors a perpetual to spot in the absence of expiry. It also makes the carry cost visible in real time, which is information a traditional futures curve only implies.
Funding as a signal
Because funding reflects positioning, it reads as a sentiment indicator.
Persistently high positive funding means crowded longs paying substantially to maintain exposure. That is both a bullish sentiment reading and a warning: crowded positioning with a carrying cost is fragile, and such periods often precede sharp liquidation-driven reversals.
The cash-and-carry trade
The clearest trade the mechanism creates, and a substantial business.
When funding is strongly positive, go long spot and short perp in equal size. You are market neutral, and you collect funding from the crowded longs.
During enthusiastic periods this has produced annualised returns far above conventional carry trades. The risks are real: funding can flip, the two legs sit on different venues so you carry counterparty exposure on both, and a sharp move can trigger liquidation on the short leg before the spot leg can be mobilised as collateral.
It is the same carry structure found everywhere: steady income, occasional sharp loss.
Liquidation cascades
Perpetuals are heavily leveraged, often 10x or more, so positions liquidate readily.
Forced liquidation is a market order, which pushes price further, which liquidates more positions. These cascades are a defining feature of crypto and explain many of its largest single-day moves, which are mechanical rather than informational.
Publicly available open interest and funding data make crowded, leveraged positioning visible in advance, which is why watching them is standard practice.
High open interest plus extreme funding is a setup, not a signal to follow the crowd. It marks a market where a modest move can trigger a large mechanical one.