Hubble has a hybrid fee system, consisting of a one-time Minting Fee, and Stability Fees. Both fees are reflected in the USDH debt on a loan.
All loans on Hubble are subject to a minting fee that varies by vault. This fee is added to a user's debt at the time of minting, and is not recurring. For example, if a user borrows 100 USDH against SOL, their debt will be 100.5 USDH, accounting for the 0.5% minting fee applied to the DeFi Treasury vault.
Note, if a user has an active loan, and borrows additional USDH on that loan, the 0.5% Minting Fee also applies to that borrowing action.
Stability Fees are synonymous with Interest Rates, and are referred to as Stability Fees as these fees play a part in USDH peg stability. Like Interest Rates, if your loan is subject to a Stability Fee, your debt will increase over time.
Stability Fees vary between vaults. Vaults that contain high-risk assets will typically have higher Stability Fees than vaults with low-risk assets.
Stability Fees can be used to adjust USDH demand and supply, and can be adjusted at any time. Once governance is active, Stability Fee adjustments will be subject to governance votes.