> ## Documentation Index
> Fetch the complete documentation index at: https://docs.stratareserve.co/llms.txt
> Use this file to discover all available pages before exploring further.

# srUSD Monetary System

> How srUSD is issued, capped, and kept redeemable across the Strata system.

srUSD is Strata's stable settlement unit: a collateralized digital dollar backed
by tokenized reserves and **redeemable 1:1 for USDC on-chain**. This page covers
how it is issued and supply-controlled. For the peg floor, see
[Collateral & Peg](/protocol/collateral-and-peg).

## Design goals

<CardGroup cols={2}>
  <Card title="Neutral settlement" icon="scale-balanced">
    A non-yield-bearing, fully-redeemable unit usable as settlement and collateral
    across every Strata engine.
  </Card>

  <Card title="Real backing" icon="vault">
    Backed by tokenized silver reserves and approved collateral, not by
    projections or endogenous tokens.
  </Card>

  <Card title="Mechanistic redeemability" icon="arrows-rotate">
    A contract-level redemption path, not trust-and-intervention.
  </Card>

  <Card title="Coherent risk" icon="gauge">
    Issuance gated by a shared risk framework rather than per-engine logic.
  </Card>
</CardGroup>

## Issuance and supply control

Every engine that can mint srUSD routes through a global money-policy controller
and engine registry. These enforce:

* **System-wide caps** — an absolute ceiling on outstanding srUSD
* **Per-SPV caps** — limits on issuance against any single vehicle
* **Per-engine caps** — limits on how much any one engine can mint
* **Throttles** — rate limits on issuance changes

<Info>
  This is why Money is the **control plane**: no engine issues srUSD outside the
  caps and throttles the controller enforces. Launch capacity is \~\$250M srUSD.
</Info>

## Collateral classes

srUSD is minted against approved collateral with conservative collateral ratios:

| Asset type      | Collateral ratio |
| --------------- | ---------------- |
| Vaulted silver  | 125–150%         |
| Gold            | 150–200%         |
| Royalty streams | 500–800%         |
| Private credit  | 600–1000%        |

Collateral eligibility and ratios are set by the Risk Committee through the
shared risk framework. See [Governance](/protocol/governance).

## Companion instrument: srSILVER

srSILVER is a tokenized representation of vaulted silver, backed by SPV-held
reserves and redeemable for USDC at spot silver value. It provides commodity
exposure and serves as DeFi collateral. Launch capacity \~\$50M.

<Card title="Collateral & peg mechanics" icon="anchor" href="/protocol/collateral-and-peg">
  The autonomous redemption floor that keeps srUSD near \$1.
</Card>