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stable-lending

Spark Savings (sUSDS)

Rejected
Max sleeve
Reviewed
2026-08-01 · v1
Next review
2026-11-01
Research basis
Individual research
Chains
Ethereum · sovereign
Symbols
SUSDS USDS

Rejected venues wait the longest for re-review; a rejection has to earn another look before the scheduled date.

REJECTED AS A DUPLICATE RECORD, NOT AS A REJECTION OF sUSDS. The prior description was factually wrong: Spark’s own documentation says sUSDS is a Sky product earning 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. Maintaining two verdicts for one instrument would double-count exposure and create contradictory monitoring. Keep this record rejected as an alias and use sky-lending as the canonical sUSDS decision. A distinct Spark V2 product such as spUSDC requires its own symbol, slug and underwriting.

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 is stable while the conversion rate to USDS rises as the governance-set savings rate accrues. Calling this entry an additional 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 relevant control set for this alias is therefore the same Ethereum Sky governance and vault authority map—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. No sUSDS principal loss or unexplained conversion-rate decline was identified in the reviewed official materials. That limited finding should not be read as proof of absence: the canonical sky-lending memo owns incident monitoring for 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 are not approved by either this alias or the canonical Ethereum-only Sky memo. DEX liquidity is 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 available liquidity.

Comparison and decision

The meaningful comparison is not direct sUSDS versus a Spark wrapper: both registry records currently identify sUSDS. Spark Savings V2 tokens such as spUSDC are different instruments because SLL strategies and Spark governance determine their yield and liquidity. The decision is therefore administrative but consequential: retain zero allocation on this duplicate, route every sUSDS recommendation and cap through sky-lending, and do not infer rejection of the underlying product.

Observable reopening conditions

Reopen this slug only if its symbols and contract addresses change to a genuinely distinct Spark product with a separately observable yield source, control set and loss waterfall. 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.

Inherited controls

The verdict above grades the protocol layer. Every position also inherits the asset it holds and the chain it settles on. The least safe layer sets the position’s grade, and the position table names which one that is.

ChainVerdictGradeControl constraint
EthereumApproved sovereign No sequencer, no upgrade key, no operator who can be compelled — rule changes require social consensus.
AssetGradeWho can freeze it
SUSDS hybrid Savings USDS. Inherits the USDS reserve mix.
USDS hybrid Sky/Maker successor to DAI. Reserve mix includes real-world assets held by custodians who can be compelled.
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