USDGPool

USDGPool is the shared ERC-4626 vault that funds every book. Suppliers deposit USDG and receive sUSDG, a share token whose price rises as borrowers pay interest. Stockline (the core) is the only borrower; it pulls idle cash and reports interest and repayments. Withdrawals are synchronous and limited by idle cash, and the guardian pause sets the withdrawal limit to zero. USDGPool lets you:

Deposit USDG and receive sUSDG shares
Withdraw or redeem USDG when idle cash allows and the protocol is not paused
Read cash, borrowed principal, and accrued interest that back the shares
Receive donated yield from CreatorFeeRouter with no new shares minted
Receive reserve top-ups from FeeCollector after a bad-debt write-off

Addresses per network. Every address is also on Addresses.

Network	Address
Robinhood Chain testnet	0x21fF7B388b61FBE2DfD932bfD100C032C965fB0a

The source code is src/core/USDGPool.sol on GitHub. The ABI is /abis/USDGPool.json.

Write methods

borrow

function borrow(uint256 amount) external nonReentrant

Moves amount idle USDG to the core and books it as borrowed principal. Only Stockline can call it. Reverts with InsufficientCash when amount exceeds cash. Total assets do not change.

Core only. Reverts with NotCore for any other caller.

Core pulls idle USDG. totalAssets stays flat: cash down, borrowed up.

Input parameters

Name	Type	Description
amount	`uint256`	USDG to lend to the core.

repay

function repay(uint256 amount) external nonReentrant

Pulls USDG from the core and applies it to accrued interest first, then principal. Only Stockline can call it. Reverts with RepayExceedsDebt if the received amount exceeds borrowed plus accrued interest.

Core only.

Pays accrued interest first, then principal. totalAssets unchanged.

Input parameters

Name	Type	Description
amount	`uint256`	USDG to pull from the core.

accrue

function accrue(uint256 interest) external

Records interest USDG as owed by borrowers. Only Stockline can call it, after the reserve-factor split. The share price rises immediately even though the cash arrives later on repay.

Core only.

Core reports interest after the reserve-factor split. Share price rises.

Input parameters

Name	Type	Description
interest	`uint256`	Supplier interest to add, in USDG native units.

realizeBadDebt

function realizeBadDebt(uint256 amount) external override nonReentrant

Removes amount from what the pool expects back, accrued interest first, then principal. Only Stockline can call it. The share price falls. FeeCollector.coverBadDebt can later restore cash from the reserve.

Core only. This is the last step of the bad-debt waterfall and reduces every holder’s claim pro rata.

Socializes a recognized shortfall. Accrued interest first, then principal. Share price falls. SPEC: Reserve and Backstop absorb first once they exist; this is the last waterfall step.

Input parameters

Name	Type	Description
amount	`uint256`	USDG shortfall to socialize.

donate

function donate(uint256 amount) external nonReentrant

Pulls amount USDG from the yield distributor and adds it to cash without minting shares. Only the configured yieldDistributor (CreatorFeeRouter) can call it. Every sUSDG holder gains pro rata.

Distributor only. Reverts with NotDistributor otherwise.

CreatorFeeRouter path. Increases cash with no new shares, so every holder earns pro rata.

Input parameters

Name	Type	Description
amount	`uint256`	USDG to donate.

restore

function restore(uint256 amount) external override nonReentrant

Pulls amount USDG from the caller and adds it to cash without minting shares. Permissionless. FeeCollector uses it to spend reserve on bad debt.

The caller must approve USDGPool for the amount. USDG sent here is given to all share holders and cannot be recovered.

Permissionless cash add, no new shares. FeeCollector uses this to spend reserve on bad debt.

Input parameters

Name	Type	Description
amount	`uint256`	USDG to add.

Read methods

totalAssets

function totalAssets() public view override returns (uint256)

Returns cash plus borrowed principal plus accrued interest. Backing is tracked internally, so a raw USDG transfer to the pool does not change the share price. Return values

Type	Description
`uint256`	Total USDG backing sUSDG, in USDG native units.

maxWithdraw

function maxWithdraw(address owner) public view override returns (uint256)

Returns the most USDG owner can withdraw right now: the lesser of their share value and idle cash, or 0 while the guardian pause is active.

Cap assets by idle cash. Guardian pause (via core) returns 0.

Input parameters

Name	Type	Description
owner	`address`	The share holder.

Return values

Type	Description
`uint256`	USDG amount.

maxRedeem

function maxRedeem(address owner) public view override returns (uint256)

Returns the most shares owner can redeem right now, capped by idle cash and 0 while paused, so redeem and withdraw stay consistent.

Same cash/pause cap, in shares, so redeem and withdraw stay consistent.

Input parameters

Name	Type	Description
owner	`address`	The share holder.

Return values

Type	Description
`uint256`	sUSDG share amount.

Events

Borrow

event Borrow(address indexed core, uint256 amount)

Fires when the core draws idle USDG.

Repay

event Repay(
    address indexed core,
    uint256 amount,
    uint256 interestPaid,
    uint256 principalPaid
)

Fires when the core repays, with the split between interest and principal.

Accrue

event Accrue(uint256 interest)

Fires when the core reports new supplier interest.

Donate

event Donate(address indexed from, uint256 amount)

Fires when the yield distributor adds USDG without minting shares.

Restore

event Restore(address indexed from, uint256 amount)

Fires when anyone adds USDG through restore, typically FeeCollector covering bad debt.

BadDebt

event BadDebt(uint256 amount)

Fires when a shortfall is socialized, with the total removed from interest and principal.

Errors

NotCore

error NotCore()

Only Stockline can borrow, repay, accrue, or realize bad debt.

NotDistributor

error NotDistributor()

Only the yield distributor can donate.

ZeroAddress

error ZeroAddress()

The core or distributor address was zero at deployment.

ZeroAmount

error ZeroAmount()

An amount was zero, or a transfer delivered zero tokens.

InsufficientCash

error InsufficientCash()

The requested amount exceeds idle cash.

RepayExceedsDebt

error RepayExceedsDebt()

The core tried to repay more than borrowed plus accrued interest.

Introduction

Using Stockline

Concepts

Developers

Ecosystem

Resources

Write methods

borrow

repay

accrue

realizeBadDebt

donate

restore

Read methods

totalAssets

maxWithdraw

maxRedeem

Events

Borrow

Repay

Accrue

Donate

Restore

BadDebt

Errors

NotCore

NotDistributor

ZeroAddress

ZeroAmount

InsufficientCash

RepayExceedsDebt

​Write methods

​borrow

​repay

​accrue

​realizeBadDebt

​donate

​restore

​Read methods

​totalAssets

​maxWithdraw

​maxRedeem

​Events

​Borrow

​Repay

​Accrue

​Donate

​Restore

​BadDebt

​Errors

​NotCore

​NotDistributor

​ZeroAddress

​ZeroAmount

​InsufficientCash

​RepayExceedsDebt

Write methods

borrow

repay

accrue

realizeBadDebt

donate

restore

Read methods

totalAssets

maxWithdraw

maxRedeem

Events

Borrow

Repay

Accrue

Donate

Restore

BadDebt

Errors

NotCore

NotDistributor

ZeroAddress

ZeroAmount

InsufficientCash

RepayExceedsDebt