Getting started

Parameters

Every limit, ratio and fee in Plumb. They are constants compiled into the program; no one can change them without upgrading it.

Collateral and debt

Parameter	Value	Notes
Collateral	JitoSOL	Classic SPL token, 9 decimals. No other collateral is accepted.
Stablecoin	PLMB	Classic SPL token, 6 decimals. Minted only by the branch; no freeze authority.
Minimum collateral ratio	150%	A trove below it can be liquidated, and can't borrow or withdraw.
Branch ratio for new debt	180%	Borrowing, and withdrawing collateral that backs debt, must leave the whole branch at 180% or more.
Minimum debt	100 PLMB	To open a trove and on every new borrow. Repaying below it is allowed.
Debt ceiling	10,000,000 PLMB	The branch can't take new debt past it. Interest can still accrue above it.

Rates and interest

Parameter	Value	Notes
Rates	1% to 16% a year	Sixteen rates, one percentage point apart.
Accrual	Every second	Simple interest at the nominal rate, added to debt each time a rate is settled.
Rate change fee	0.5% of debt	Charged only within 7 days of opening or of the last change. Paid to the treasury.
Interest to the stability pool	70%	Added to depositors' balances in proportion to their deposits.
Interest to the treasury	30%	All of it when the pool is empty.

Redemptions

Parameter	Value	Notes
Fee floor	0.5%	The fee when no redemption has happened for a while.
Fee rise	Half the share of debt redeemed	Redeeming 2% of the branch's debt adds 1 point to the fee.
Fee decay	Halves every hour	The extra above 0.5% halves for every whole hour since the last redemption.
Fee cap	10%
Order	Lowest rate first	One rate per transaction, pro rata within it.

Liquidations

Parameter	Value	Notes
Trigger	Below 150%	Anyone can call it. There is no caller reward.
Pool's share	Up to 110% of the debt it repays	Valued at the program's price.
Surplus	Stays with the borrower	As JitoSOL in the trove, withdrawable without a price.
Shortfall	Shared by other troves	Debt and collateral the pool can't take, in proportion to their collateral.

Price

Parameter	Value
Sources	Pyth SOL/USD and JitoSOL/USD, the Jito stake pool account
Rule	The lower of SOL/USD × stake rate and JitoSOL/USD
Maximum price age	120 seconds
Maximum confidence band	1% of the price, subtracted from it
Stake pool	Must be updated for the current epoch

Capacity

Parameter	Value	Notes
Troves per rate	16	A full rate refuses new troves; pick another one.
Troves per wallet	1	Per branch.
Stability pool depositors	16	A seat frees up when a depositor withdraws everything.

# Parameters

Every limit, ratio and fee in Plumb. They are constants compiled into the program; no one can change them without upgrading it.

## Collateral and debt

| Parameter | Value | Notes |
| --- | --- | --- |
| Collateral | JitoSOL | Classic SPL token, 9 decimals. No other collateral is accepted. |
| Stablecoin | PLMB | Classic SPL token, 6 decimals. Minted only by the branch; no freeze authority. |
| Minimum collateral ratio | 150% | A trove below it can be liquidated, and can't borrow or withdraw. |
| Branch ratio for new debt | 180% | Borrowing, and withdrawing collateral that backs debt, must leave the whole branch at 180% or more. |
| Minimum debt | 100 PLMB | To open a trove and on every new borrow. Repaying below it is allowed. |
| Debt ceiling | 10,000,000 PLMB | The branch can't take new debt past it. Interest can still accrue above it. |

## Rates and interest

| Parameter | Value | Notes |
| --- | --- | --- |
| Rates | 1% to 16% a year | Sixteen rates, one percentage point apart. |
| Accrual | Every second | Simple interest at the nominal rate, added to debt each time a rate is settled. |
| Rate change fee | 0.5% of debt | Charged only within 7 days of opening or of the last change. Paid to the treasury. |
| Interest to the stability pool | 70% | Added to depositors' balances in proportion to their deposits. |
| Interest to the treasury | 30% | All of it when the pool is empty. |

## Redemptions

| Parameter | Value | Notes |
| --- | --- | --- |
| Fee floor | 0.5% | The fee when no redemption has happened for a while. |
| Fee rise | Half the share of debt redeemed | Redeeming 2% of the branch's debt adds 1 point to the fee. |
| Fee decay | Halves every hour | The extra above 0.5% halves for every whole hour since the last redemption. |
| Fee cap | 10% | |
| Order | Lowest rate first | One rate per transaction, pro rata within it. |

## Liquidations

| Parameter | Value | Notes |
| --- | --- | --- |
| Trigger | Below 150% | Anyone can call it. There is no caller reward. |
| Pool's share | Up to 110% of the debt it repays | Valued at the program's price. |
| Surplus | Stays with the borrower | As JitoSOL in the trove, withdrawable without a price. |
| Shortfall | Shared by other troves | Debt and collateral the pool can't take, in proportion to their collateral. |

## Price

| Parameter | Value |
| --- | --- |
| Sources | Pyth SOL/USD and JitoSOL/USD, the Jito stake pool account |
| Rule | The lower of SOL/USD × stake rate and JitoSOL/USD |
| Maximum price age | 120 seconds |
| Maximum confidence band | 1% of the price, subtracted from it |
| Stake pool | Must be updated for the current epoch |

## Capacity

| Parameter | Value | Notes |
| --- | --- | --- |
| Troves per rate | 16 | A full rate refuses new troves; pick another one. |
| Troves per wallet | 1 | Per branch. |
| Stability pool depositors | 16 | A seat frees up when a depositor withdraws everything. |

> [!INFO]
> These limits keep every transaction inside Solana's account and compute limits: a liquidation touches every rate that holds debt, and a pool deposit settles all of them first. See [Interest accounting](/docs/accounting).