Spark Savings (sUSDS)

We reject this duplicate record, not sUSDS itself. The prior description was factually wrong: Spark’s own documentation says sUSDS is a Sky product that earns the Sky Savings Rate, not a Spark Savings V2 wrapper routed through the Spark Liquidity Layer. This slug and the approved-with-limits sky-lending memo name the same symbols and economic claim. Keeping two verdicts for one instrument would double-count exposure and create conflicting monitoring. Keep this record rejected as an alias and use sky-lending as the main sUSDS decision. A distinct Spark V2 product such as spUSDC requires its own symbol, slug and review.

Review triggers: events that reopen the verdict
• Treat the live slug as an alias of the Ethereum USDS and sUSDS contracts already governed by sky-lending; reopen within 5 business days if a symbol or contract changes
• Any catalog or exposure report counting this alias as a distinct economic claim fails the duplicate-identity control
• A replacement product reopens only after distinct symbols and contracts, a mapped yield source and control set, six months of production history, and three proposed-size entry and exit tests

Watched nightly: a warning on its venues or files, or a cited document that changes, reopens the memo. The first confirmation is due 2026-11-01.

The research file

Classification correction and mechanism

Spark lists Savings USDS as sUSDS backed by USDS, with the Sky Savings Rate as its yield source and Sky as operator. It separately lists spUSDC and other V2 vaults whose yield comes from the Spark Liquidity Layer. sUSDS is an ERC-4626 wrapper: a holder’s token balance stays stable while the conversion rate to USDS rises as the governance-set savings rate accrues. Calling this entry another SLL allocation layer therefore misstates the asset. It is the same sUSDS exposure already assessed under sky-lending.

Who controls it

Sky Governance sets the Sky Savings Rate; Spark states that it has no control over that rate. Ethereum sUSDS relies on the Sky savings implementation. L2 representations depend on separate cross-chain contracts, rate oracles and PSM administration and do not inherit the canonical memo’s Ethereum approval. The controls for this alias are therefore the same Ethereum Sky governance and vault authorities, not an sUSDS vault curator.

Failure and assurance record

Spark publishes dedicated sUSDS security reviews from ChainSecurity and Cantina and separate reviews for the cross-chain PSM and oracle components. The reviewed official materials identified no sUSDS principal loss or unexplained decline in the conversion rate. That limited finding does not prove that no such event occurred: the canonical sky-lending memo tracks incidents involving the underlying USDS balance sheet, governance history and 2023 stablecoin contagion. This alias must never create a second, narrower incident record.

Exit and liquidity

Native Ethereum USDS deposits and withdrawals have no stated slippage. Base and Arbitrum Spark PSM routes are separate chain exposures and neither this alias nor the canonical Ethereum-only Sky memo approves them. DEX liquidity offers a secondary route. Proposed-size exit capacity and bridge/oracle freshness belong in the single sky-lending exposure limit; counting this alias separately would falsely multiply the available liquidity.

Comparison and decision

The useful comparison is not direct sUSDS versus a Spark wrapper: both registry records now identify sUSDS. Spark Savings V2 tokens such as spUSDC are different instruments because SLL strategies and Spark governance set their yield and liquidity. The decision is administrative but has consequences: keep this duplicate in research-only status, route every sUSDS recommendation and cap through sky-lending, and do not treat the decision as a rejection of the underlying product.

Observable reopening conditions

Reopen this slug only if its symbols and contract addresses change to a truly distinct Spark product with a separate yield source, set of controls and loss waterfall that we can observe. Then require a full contract-and-chain inventory, current audits, named governance authorities, six months of production history and proposed-size entry and exit tests. If it continues to mean sUSDS, merge or archive the alias and keep all limits, incidents and review dates on sky-lending.

Sources

The claims above trace to these. Where a number could not be independently verified, the thesis says so.

• Spark docs — Savings product taxonomy and risk architecture · primary · accessed 2026-08-14
  Supports: sUSDS is a Sky product, Sky Savings Rate, Spark V2 distinction, ERC-4626, deposit and withdrawal mechanics
• Spark docs — sUSDS implementation · primary · accessed 2026-08-14
  Supports: Ethereum sUSDS contract, accumulating conversion rate, ERC-4626 mechanics
• Spark docs — cross-chain USDS and sUSDS · primary · accessed 2026-08-14
  Supports: L2 token architecture, bridge dependency, cross-chain administration
• Spark docs — cross-chain Savings Rate oracle · primary · accessed 2026-08-14
  Supports: L2 conversion-rate reporting, oracle dependency, sUSDS accumulation
• Spark docs — Spark PSM · primary · accessed 2026-08-14
  Supports: Base and Arbitrum exits, USDS sUSDS USDC swaps, no protocol fee or slippage beyond gas
• Spark docs — security audits · primary · accessed 2026-08-14
  Supports: sUSDS audits, PSM audits, cross-chain oracle audits, audit scope
• ChainSecurity — sUSDS security assessment · primary · accessed 2026-08-14
  Supports: Ethereum implementation, L2 implementation, privileged controls, assessment scope

Inherited controls

The research above describes the protocol layer. Every position also inherits the asset it holds and the chain it settles on. The layer with the most administrative power sets the position’s effective control; that describes control, not quality or suitability.