Perpetual futures are a type of cryptocurrency derivative. While perpetual futures are very similar to expiry futures, they differ in two significant ways:
Expiry
Where expiry futures have expiry dates set in advance, perpetual futures don’t, meaning buyers and sellers can hypothetically keep their positions open 'perpetually' — as long as their account holds enough margin to cover losses and prevent liquidations.
Funding fees
To avoid perpetual futures diverging significantly from the asset’s spot price, funding fees help discourage major deviations. It's important to note that the funding rate is a fee exchanged between the long and short parties — not a fee collected by the exchange.
