On-chain & RWA collateralRank #3
USDSSky USDS
Sky Protocol
- Market cap
- $8.7B
- Circulating supply
- 8.7B
- Networks
- 1
EIP/ERC standards & compliance
Full USDS profile: ERC-20, permit, proxy patterns, cross-chain, flash loans, and compliance EIPs — with implementation notes and verified contract context.
Overview
Upgraded successor to DAI, launched with the MakerDAO→Sky Protocol rebrand in 2024. Interchangeable with DAI at 1:1 via DaiUsds.sol migration contract. Key additions: upgradeable proxy architecture, Sky Savings Rate, and official Ethereum–Solana bridge availability (Skylink / Wormhole NTT, later migrated to LayerZero infrastructure — not a separate native Solana issuance).
Supply by chain
Market cap
$8.7B
Circulating supply
8.7B
Supply chains
7
| Chain | Supply | Market cap | Share |
|---|---|---|---|
| Ethereum | 8.2B | $8.2B | 94.2% |
| Base | 146.5M | $146M | 1.7% |
| OP Mainnet | 100.3M | $100M | 1.2% |
| Unichain | 100.0M | $100M | 1.1% |
| Arbitrum | 99.7M | $100M | 1.1% |
| Solana | 54.7M | $55M | 0.63% |
| Avalanche | 11 | $11 | 0.00% |
| Current circulating supply by chain from DeFiLlama. Small supply footprints are grouped after the top 12 chains and may include bridged or non-curated deployments. | |||
Features
Engineering-oriented breakdown of capabilities: standards, who they matter for, integration rationale, per-feature risks, and vetted external references (specs, docs, verified source).
Protocol repo: github.com/makerdaoPrimary Ethereum verified source: Etherscan
| Feature | Standards | Audience | Why it matters | Risk / caveat | References |
|---|---|---|---|---|---|
1:1 DAI migration stability | — | User | Use DaiUsds migration contract for 1:1 conversion — avoid thin pools for migration volume. | Governance can alter migration contracts; pin addresses from official deployments. | |
Sky Savings Rate — sUSDS yield | User | SSR accrues in sUSDS shares — treat as ERC-4626 vault with protocol-specific risks. | SSR changes; upgradeable USDS implementation interacts with savings layer. | ||
ERC1967Proxy upgradeable compliance | Corporate | Token logic can change via proxy — monitor implementation slot and governance upgrades. | Upgradeability increases governance/capture risk vs immutable DAI token. | ||
Sky Token Rewards governance | — | User | Incentives for holding/migrating — relevant for wallet displays and staking integrations. | Reward parameters change; smart contract risk in distributor contracts. | |
Ethereum–Solana bridge cross chain |
| Both | USDS on Solana is bridged from Ethereum via Skylink (Wormhole NTT burn-and-mint with rate limits) — not a separate native Solana mint. Integrations must treat bridged balance as distinct from canonical Ethereum supply. | Cross-chain messaging risk (Wormhole guardian set) in addition to base USDS risk; rate limits can stall large flows. |
EIP / ERC support matrix
Standards & compliance support for USDS. Click an EIP to jump to the global deep-dive section.
| Standard | Status | Notes |
|---|---|---|
| Core | ||
| ERC-20 Fungible token standard | Implemented | Clean ERC-20 surface today with no current compliance hooks, but the upgradeable proxy means integrators should watch implementation changes over time. |
| Signatures & typed data | ||
| EIP-712 Typed structured data signing | Implemented | Full EIP-712 compliance with EIP-5267 discovery. Tools and wallets can query the contract for its domain parameters rather than hardcoding them. |
| EIP-2612 Permit — gasless ERC-20 approval | Implemented | Drop-in replacement for USDC permit() flows — same ABI, same function signatures. Any integration that supports USDC EIP-2612 works with USDS without code changes. |
| EIP-3009 transferWithAuthorization | Not implemented | Payment relayers that require atomic signed transfers must compose permit() + transferFrom() for USDS. If EIP-3009 is a hard requirement, USDC or PYUSD are the appropriate alternatives. |
| EIP-1271 Signature validation for smart contracts | Implemented | Without EIP-1271, permit() only works for EOA private keys. With it, any smart contract wallet or institutional custody solution (Safe, Fireblocks smart contract wallet) can sign USDS permits — critical for institutional DeFi adoption. |
| Upgradeability & proxies | ||
| EIP-1967 Standard proxy storage slots | Implemented | Allows Sky Protocol to add features (freeze function, cross-chain extensions) via governance without token migration. Standard proxy slots mean monitoring tools work out of the box. |
| EIP-1822 UUPS — universal upgradeable proxy | Implemented | UUPS is the current OpenZeppelin recommendation for new deployments. Cheaper proxies reduce deployment cost for protocols that fork or wrap sUSDS. |
| Vaults & yield | ||
| ERC-4626 Tokenized yield vault standard | Implemented | Any protocol that integrates the ERC-4626 interface (Aave, Compound, Yearn, Gearbox, EigenLayer) gets sUSDS support automatically. This is the single biggest advantage of sUSDS over DAI's DSR — the DSR has no standard interface, requiring custom integrations per protocol. |
| Compliance | ||
| Freeze Address freezing / blacklisting | Not implemented | Treat current USDS transfers as permissionless, while monitoring implementation upgrades if your product depends on that assumption. |
| Seize Fund seizure / clawback | Not implemented | Current supply tracking is unaffected by administrative seizure logic because no such path exists in the live implementation. |
| Pause Global transfer pause | Not implemented | Currently, USDS transfers cannot be globally halted. The proxy pattern means this could change — monitor governance. |
| Cross-chain | ||
| ERC-7802 Crosschain token interface | Alternative | Via Wormhole NTT: Wormhole Native Token Transfers — burn-and-mint with built-in rate-limiting. Fulfils cross-chain fungibility without the ERC-7802 interface. |
| Flash Loans | ||
| ERC-3156 Flash loans | Alternative | Via DssFlash + DaiUsds: Flash-mint DAI via DssFlash (ERC-3156) then convert to USDS via the official DaiUsds.sol converter in a single transaction. Issuer-ecosystem path — not a direct ERC-3156 interface on USDS, but achieves flash liquidity using Maker/Sky's own contracts. |
| Data sourced from verified Etherscan contract source code. Implementations may differ across networks — always verify on the specific chain you integrate with. | ||
Technical notes
- 18 decimals.
- sUSDS uses chi rate accumulator — convertToAssets() calculates theoretical current chi on-the-fly even if drip() hasn't been called.
- No fees assessed and fees CANNOT be enabled (encoded in contract).
- UUPS (EIP-1822) upgrade pattern on sUSDS — if implementation without upgradeTo() is deployed, contract becomes permanently non-upgradeable (safety property).
- Solana exposure is via Skylink / Wormhole NTT (bridged), not a duplicate native mint on Solana.
- DaiUsds.sol: permissionless bidirectional DAI↔USDS 1:1 converter.
Reserves & peg
- Reserves
- Identical to DAI — shared MCD protocol collateral pool
- Collateral
- On-chain crypto and RWAs (shared with DAI)
- Peg mechanism
- Same as DAI — PSM, SSR, liquidation mechanisms
- Auditor
- Shared with Sky Protocol audits
Ecosystem
- DeFi integration
- Aave, Spark (Sky native lending), Yearn
- Yield
- sUSDS ~4.75% SSR
Risk factors
mediumUpgradeability introduces governance risklowUpgradeability changes trust assumptions vs DAIlowSlower adoption than DAI
Technical references
Official docs
Sky USDS
sky.money
Source code
GitHub repository
makerdao
Verified contract · Ethereum
USDS + sUSDS (Sky Protocol)
0xdC03…384F· block 20,690,000
Block explorers
Networks & contracts
Deployments by chain — primary rows are highlighted. Always verify addresses against issuer docs before mainnet integrations.
| Network | Standard | Contract | Explorer |
|---|---|---|---|
EthereumPrimary | ERC-20 | 0xdC035D45d973E3EC169d2276DDab16f1e407384FERC1967Proxy upgradeable | View |
Engineering deep dive
Integration notes
USDS shares Sky Protocol backing with DAI—treat migration and upgradeability as first-class concerns. Prefer the documented DaiUsds migration helpers for 1:1 moves instead of routing through shallow pools.
Roadmap awareness
USDS is upgradeable, so if your product depends on its current permissionless transfer surface, monitor Sky governance and implementation changes rather than assuming DAI-like immutability.