A funding rate is the periodic payment exchanged between long and short holders of a perpetual futures contract.

A funding rate is the periodic payment exchanged between long and short holders of a perpetual futures contract. Its purpose is to keep the contract price anchored to a reference index rather than letting the perpetual future drift too far from the underlying market.

A perpetual future differs from a dated future because it has no expiry. Without expiry, there is no settlement date that forces the contract to converge to the spot market at maturity. The funding mechanism is the main tool used to create that convergence pressure on an ongoing basis.

When a perpetual future trades above its reference index, the funding rate is typically positive. In that state, long holders pay short holders. This raises the carrying cost of holding the long side and can reduce demand for further long exposure while making short exposure relatively more attractive. That incentive tends to push the perpetual price back toward the index.

When a perpetual future trades below its reference index, the funding rate is typically negative. In that state, short holders pay long holders. This raises the carrying cost of staying short and can make long exposure relatively more attractive. That incentive tends to pull the perpetual price back up toward the index.

The mechanism is economic rather than mechanical. Funding does not directly move the price. Instead, it changes the relative cost of holding long and short positions, which encourages trading that narrows the gap between the perpetual futures price and the index.

For quantitative research, the useful framing is basis control through periodic transfers. The sign and magnitude of funding reflect the direction and intensity of the imbalance between the perpetual market and the index reference. A persistently positive funding rate is consistent with a market where the perpetual future has been trading rich to the index. A persistently negative funding rate is consistent with a market where it has been trading cheap to the index.

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