Note: Since the Fringe platform uses lending primitives to allow users to mint stablecoins, the terms “minters” and “borrowers” are used interchangeably to refer to users minting stablecoins.

Depositing collateral

Borrowers can deposit whitelisted assets to the USB Stablecoin facility into a user-specific and asset-specific Collateral Safe. In return for their assets, users receive a non-transferable token, PIT, which standardizes their collateral assets. Each PIT is pegged to 1 USD. As such, PIT represents the borrower’s borrowing capacity in USD. The amount of PIT tokens awarded to the borrower for the assets they deposit is based on the LVR for the asset deposited.

$PIT value can be calculated using the following formula:

The amount of a user’s PIT (i.e. borrowing capacity) will fluctuate with the market price of the assets they deposited as collateral.

Minting $USB

Borrowers can mint USB stablecoins ($USB) based on their borrowing capacity (i.e. PIT tokens). It can be thought of as a $USB loan that eventually will need to be paid back. The remainder of this description will use the analogy of a $USB loan. If the borrower has remaining borrowing capacity (i.e. remaining PIT tokens), the loan amount can be extended by borrowing additional USB stablecoins.

Interest charges on open positions

The USB Stablecoin facility’s prevailing Stability Fee can be thought of as the ‘interest rate’ charged to open $USB loan positions. Interest is charged on each of the borrower’s open loan positions. This is calculated per block and is accrued to each loan position.

The platform presents both the loan principal amount and the accrued interest amount for each loan. Accrual of interest effectively increases the amount the borrower needs to repay to settle the loan. Accrual of interest also reduces the amount of the borrower’s available PIT tokens. i.e. reduces their remaining borrowing capacity.

Repaying USB positions

Any repayment of USB stablecoins to settle a loan position is first applied to the accrued interest amount and then applied to the loan principal amount. Repaying any part of a loan increases the Collateral Safe’s borrowing capacity. i.e. increases the amount of available PIT tokens.

Fringe supports Atomic Repayments, which allows a borrower to repay a loan in part or in whole using collateral assets that are securing the loan. This allows borrowers to settle loans without needing to have the capital assets on-hand to repay the loan. Atomic Repayments employ a third-party DEX aggregator to swap collateral assets for the capital (lending) asset to then repay the loan using the swapped capital assets.

Atomic Repayments are available so long as there is a liquid trading market to enable the swap between the collateral asset and the capital asset.