Interdax’s funding mechanism ensures that the price of a perpetual swap contract closely tracks the price of the underlying asset. Unlike most cryptocurrency perpetuals, Interdax's contracts do not have eight-hour funding periods.
Interest rates are calculated and compounded continuously for open positions to ensuring a smoother adjustment mechanism for the index price (=mark price) for perpetuals.
The daily interest rate is calculated as:
The formula for the daily interest rate is applicable if the bid-ask spread is less than 20% and the interest rate is capped to max interest on each side.
If the interest rate is positive, long positions pay short positions. If the interest rate is negative, short positions pay long positions.
In the case where the mark price is significantly higher than the price of the underlying asset, a positive interest rate provides an incentive for traders to take short positions (as they will receive payments). As more traders open short positions, the price of the derivative contract should fall and quickly re-align with the price of the underlying asset.
In the case where the mark price is significantly lower than the price of the underlying asset, traders with long positions will be paid interest. As more traders go long on the derivative, the mark price will increase to match the price of the underlying asset.
Example
Suppose the daily interest rate is 0.01% and a user has a short position of 1,000 contracts of BTC-PERP with a market price of $10,000. The position will be valued at 0.1 BTC.
The interest accrued to a trader with a short position in one second will be equal to the daily interest rate:
However, a trader with a long position in the same situation would be debited 0.0116 satoshis per second.
When accumulated payments exceed the minimal threshold, they are credited to (or deducted from) the user’s balance.