How QUSDC works

What QUSDC is

QUSDC is a dollar token issued on QIE Blockchain (chain ID 1990). It is a receipt for WUSDC locked in a public vault. WUSDC itself represents USDC that has been locked in a bridge contract on Ethereum.

In the ordinary path, one USDC locked on Ethereum becomes one WUSDC on QIE, and one WUSDC locked in the vault becomes one QUSDC. The vault has a public check, invariantHolds(), that confirms locked WUSDC equals QUSDC supply. A live reserves page shows both sides of this, including any small differences.

QUSDC is not issued by Circle, and it is not native USDC. QIE Blockchain is the identity and trust layer of Web3. QIE ID is the application that provides readable names and trust scores on that chain. QUSDC is a token of the QIE ecosystem.

The path, in two steps

1. Ethereum USDC to WUSDC on QIE

Circle does not issue USDC on QIE. To bring USDC value onto QIE, a user sends USDC into the Ethereum bridge contract. A matching amount of WUSDC is then minted on QIE. Going back, WUSDC is burned on QIE and USDC is released on Ethereum.

This bridge is a trusted-operator system. The mint function on the QIE bridge does not check a cryptographic proof of an Ethereum deposit on-chain. A designated operator address can mint WUSDC on QIE and can release USDC from the Ethereum bridge. Users should understand that they are relying on that operator, and on the USDC held in the Ethereum contract, not on a trustless lock-and-mint.

2. WUSDC to QUSDC

Once a user holds WUSDC on QIE, they can deposit it into the vault contract. The vault mints the same amount of QUSDC to the user. To redeem, the user returns QUSDC to the vault; the vault burns that QUSDC and releases the WUSDC. Those vault functions are open to any holder of WUSDC or QUSDC. This is the 1:1 receipt step.

Who can mint

It is not accurate to say that QUSDC has no admin key, or that no privileged operator can issue tokens.

• The QUSDC contract has an admin role. The admin can grant or revoke VAULT_ROLE, which is the only role that can mint or burn QUSDC.
• Today, VAULT_ROLE is held only by the vault. That is the intended setup: QUSDC is minted when WUSDC is deposited, and burned when it is withdrawn.
• The same admin address is the owner of the WUSDC contract. WUSDC minting and burning are restricted to the QIE bridge, which is itself owned by the operator address.
• The vault’s burn path can burn QUSDC from an address when the vault is completing a withdrawal. That power sits with the vault role, not with ordinary users.

Current addresses are listed on the reserves page and are also public on the QIE explorer. This page does not discuss private keys, and nobody should ever be asked for one.

What backs QUSDC

QUSDC is backed by WUSDC in the vault. WUSDC is backed by USDC held in the Ethereum bridge, to the extent that the operator has minted WUSDC only against those deposits. The reserves page compares three public numbers:

• USDC held by the Ethereum bridge
• WUSDC total supply on QIE
• WUSDC in the vault, which should equal QUSDC total supply

A small difference — the Ethereum bridge holds slightly less USDC than the WUSDC supply, about 0.0018 — has been visible since at least 24 October 2026. This is dust left over from test transactions during development. It does not affect QUSDC: every QUSDC in circulation is backed 1:1 by WUSDC in the vault. The live amount is shown on the reserves page.

QUSDC also inherits the risks of USDC itself, including issuer and regulatory risk at the fiat layer. There is no third-party attestation on the reserves page; the figures are on-chain reads.

What QUSDC is not

• It is not native USDC, and it is not a Circle product.
• It is not accurate to describe QUSDC as “not wrapped” or “not bridged” in a way that hides the Ethereum USDC and WUSDC steps. QUSDC is issued on QIE, but its backing arrives through the bridge.
• It is not an algorithmic stablecoin and it is not a lending position. The vault does not use a price oracle or a liquidation engine.
• This document does not promise a peg, a price, or a return.

Contracts

Where this should replace older wording

Public pages that still need this wording applied:

• docs.stable.qie.digital — the GitBook currently says there is no admin key, that minting is permissionless without the bridge caveat, that the bridge is non-custodial, and that QUSDC is not a wrapped token.
• www.stable.qie.digital — the marketing site and its Transparency page. The Transparency page should use live on-chain figures, not placeholder circulation numbers from other networks.

The QIEDEX official token list describes QUSDC as a stablecoin pegged 1:1 with USDC and gives the correct contract. That is fine as a short label, with a link to the reserves page for the backing details.