SumUSD

SumUSD is an aggregated US-dollar stablecoin. It is backed by a diversified basket of credible, major USD stablecoins (prioritizing GENIUS-Act-compliant, US-Treasury-backed issuers), and packages them into a single, fungible dollar token you can mint and redeem on-chain.

Deposit any whitelisted collateral and receive SumUSD as a raw 1:1 unit swap (normalized for decimals). One unit of any accepted flavor mints exactly one SumUSD; every accepted stablecoin is treated as a fungible dollar.

Burn SumUSD to receive any flavor the pool holds, as a fungible 1:1 unit swap minus a per-collateral haircut (every flavor is treated as exactly $1). Moderate imbalances are tolerated at the base rate; only when a flavor drifts well off its target weight does the haircut tilt: an over-represented flavor becomes cheaper to redeem (rewarding rebalancing), while a scarce one gets progressively more expensive the closer it is to running out. The basket stays balanced and every flavor is always redeemable. The live rate is quoted before you confirm. You can also split one redemption across several flavors in a single transaction with “Split across flavors”, which is the cheaper way to exit a large amount without paying the scarcity premium on any one flavor.

Yes. The redemption haircut leaves residual value in the pool on every exit, so mark-to-market backing trends above 100% over time. The current system collateralization is shown at the top of this page.

A governance-curated whitelist, never permissionless. It prioritizes GENIUS-Act-compliant, US-Treasury-backed payment stablecoins as the core of the basket; other credible designs may be admitted under more conservative risk parameters. The convex redemption haircut keeps the basket balanced by making it progressively more expensive to drain any one flavor.

Beyond the credibility bar above, a candidate must be technically well-behaved, because the protocol accounts for collateral by its on-chain balance and treats one unit as one dollar. Required properties: standard fixed decimals; non-rebasing, so a balance changes only on transfer and never on its own; no transfer hooks or callbacks; freely transferable with no fee-on-transfer (or a negligible, disclosed one); and honest, immutable metadata. Rebasing, fee-on-transfer, and hook-bearing tokens are excluded, since any of them would silently break the 1:1 unit accounting or redemption. Every listing is a timelocked governance action, so this vetting happens before any deposit of that asset is possible.

If system backing falls below 99% (for example during a collateral de-peg), new minting pauses automatically so no one can mint into an under-backed pool. It resumes on its own once backing recovers. Redemptions always stay open so holders can exit.

SumUSD inherits the issuer and de-peg risk of its underlying stablecoins, plus smart-contract and price-oracle risk. It is not a yield product; it is a diversified, redeemable dollar. Review the contracts and whitepaper before depositing.