# Introduction & Glossary

Kasu is an RWA private credit lending platform built on Solidity smart contracts. It connects DeFi investors (Liquidity Providers) with lending entities (Pool Funds Managers) who originate loans to business borrowers. The platform uses permissioned lending pools with epoch-based clearing, KYC requirements, and a KSU token-based loyalty system.

All transactions are denominated in USDC (6 decimals). The system is deployed on Base (full deployment with KSU token) and on Plume and XDC (lite deployments without KSU token/locking/loyalty).

## Glossary

| Term                           | Definition                                                                                                                                                                                                       |
| ------------------------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| **Lending Pool**               | A permissioned pool that accepts USDC deposits from KYC'd Liquidity Providers for deployment into off-chain loans. Also an ERC-20 token representing the total pool balance relative to USDC.                    |
| **Pending Pool**               | An ERC-721 contract that holds pending deposit and withdrawal requests, issuing D-NFTs and W-NFTs as receipts.                                                                                                   |
| **Tranche**                    | An ERC-4626 vault within a lending pool representing a risk class (Junior, Mezzanine, or Senior). Each tranche has its own interest rate and loss priority. Also uses ERC-1155 for unrealized loss tokens.       |
| **Tranche Shares**             | Non-transferable ERC-20 tokens minted 1:1 with deposited USDC, representing a Liquidity Provider's proportional share of a tranche.                                                                              |
| **USDC-IOU**                   | Internal ERC-20 tokens minted by the lending pool to track the total USDC value (principal + accrued interest) within each tranche. Not directly accessible by users.                                            |
| **Epoch**                      | A fixed 7-day time period used by the system to structure deposits, withdrawals, interest accrual, and clearing.                                                                                                 |
| **Clearing Period**            | The 48-hour window at the end of each epoch when deposit and withdrawal requests are processed.                                                                                                                  |
| **D-NFT**                      | Non-transferable ERC-721 token issued by the Pending Pool as a receipt for a pending deposit request.                                                                                                            |
| **W-NFT**                      | Non-transferable ERC-721 token issued by the Pending Pool as a receipt for a pending withdrawal request.                                                                                                         |
| **First Loss Capital**         | Non-interest-generating capital provided by a Pool Funds Manager that absorbs losses before any tranche in an unrealized loss event. Can only be withdrawn when the pool is stopped and all tranches are repaid. |
| **Owed Funds**                 | The total USDC that the Pool Funds Manager must repay to the lending pool: `Pool Balance - Excess Funds`.                                                                                                        |
| **Excess Funds**               | USDC held in the lending pool available for withdrawal or draw: `Pool Balance - Owed Funds`.                                                                                                                     |
| **Owed Fees**                  | Outstanding USDC fees owed by the lending pool to the Fee Manager, accrued when interest is applied.                                                                                                             |
| **Performance Fee**            | A percentage of tranche interest allocated to the protocol. Configurable by the Kasu Admin.                                                                                                                      |
| **Ecosystem Fees**             | The portion of the Performance Fee distributed to KSU token lockers pro-rata by rKSU balance.                                                                                                                    |
| **Protocol Fees**              | The portion of the Performance Fee retained by the Kasu Protocol.                                                                                                                                                |
| **KSU**                        | The native ERC-20 token of the Kasu ecosystem (symbol: KSU, supply: 1B).                                                                                                                                         |
| **rKSU**                       | Non-transferable receipt token minted when KSU is locked. Amount depends on lock duration. Used to determine loyalty level and fee share.                                                                        |
| **Loyalty Level**              | A user's priority tier (0, 1, or 2) for deposit/withdrawal processing during clearing, derived from their rKSU-to-deposit ratio.                                                                                 |
| **Force Withdrawal**           | A withdrawal initiated by the Pool Manager that receives the highest priority level and cannot be canceled by the user.                                                                                          |
| **Force Immediate Withdrawal** | A withdrawal initiated by the Pool Manager that occurs immediately from excess funds, bypassing clearing.                                                                                                        |
| **Unrealized Loss**            | A declared loss event when off-chain borrowers fail to meet repayment obligations. Applied in order: First Loss Capital, Junior, Mezzanine, Senior.                                                              |
| **Unrealized Loss Token**      | Non-transferable ERC-1155 token minted to affected Liquidity Providers, entitling them to a proportional share of any recovered funds.                                                                           |
| **Fixed Term Deposit**         | A deposit locked for a specific duration in return for a guaranteed interest rate. Processed with highest priority upon maturity or early withdrawal request.                                                    |