Yearn — yvUSDT-1

Contract Addresses

Core yvUSDT-1 Contracts

Contract	Address	Type
yvUSDT-1 Vault	0x310B7Ea7475A0B449Cfd73bE81522F1B88eFAFaa	Yearn V3 Vault (v3.0.2), Vyper minimal proxy
Underlying asset (USDT)	0xdAC17F958D2ee523a2206206994597C13D831ec7	Tether USD
Accountant	0x5A74Cb32D36f2f517DB6f7b0A0591e09b22cDE69	Shared Yearn Accountant (0% mgmt, 10% perf)
Fee Recipient (Dumper)	0x590Dd9399bB53f1085097399C3265C7137c1C4Cf	Claims fees and routes to auctions/splitters

Governance Contracts (shared with all Yearn V3 risk-1 vaults)

Contract	Address	Configuration
Yearn V3 Role Manager	0xb3bd6B2E61753C311EFbCF0111f75D29706D9a41	Single instance for all category-1 vaults
Daddy / ySafe (Governance)	0xFEB4acf3df3cDEA7399794D0869ef76A6EfAff52	6-of-9 Gnosis Safe
Brain (Operations)	0x16388463d60FFE0661Cf7F1f31a7D658aC790ff7	3-of-8 Gnosis Safe
Security	0xe5e2Baf96198c56380dDD5E992D7d1ADa0e989c0	4-of-7 Gnosis Safe
Strategy Manager (Timelock)	0x88Ba032be87d5EF1fbE87336b7090767F367BF73	TimelockController — 7-day delay
Keeper	0x604e586F17cE106B64185A7a0d2c1Da5bAce711E	yHaaSRelayer — REPORTING only
Debt Allocator	0x1e9eB053228B1156831759401dE0E115356b8671	Minimal proxy — REPORTING + DEBT_MANAGER

Yearn V3 Infrastructure

Contract	Address
Vault Factory (v3.0.2)	0x444045c5C13C246e117eD36437303cac8E250aB0
Vault Original (v3.0.2)	0x1ab62413e0cf2eBEb73da7D40C70E7202ae14467

Strategies (2 in default queue, both with debt)

#	Strategy	Name	Current Debt (USDT)	Allocation
1	0x0963232eB842BAF53E8e517691f81745C1F228a0	MetaMorpho Vault (ymv-USDT)	3,176,868.08	43.94%
2	0x176Caf15f1793fc16898458E0ba295ec6523E9E2	Spark USDT Lender	4,052,002.50	56.06%

Previously queued, now revoked (activation = 0 at block 25521239):

• Spark USDT Lender (old) (0xED48069a2b9982B4eec646CBfA7b81d181f9400B)
• Morpho Gauntlet USDT Prime Compounder (0x6D2981FF9b8d7edbb7604de7A65BAC8694ac849F)
• Morpho Steakhouse USDT Compounder (0x0a4ea2bDe8496a878a7ca2772056a8e6fe3245c5)
• USDT Fluid Lender (0x4Bd05E6ff75b633F504F0fC501c1e257578C8A72)
• Aave V3 USDT Lender (0x27998440eC85F0DF11DED26e6aB27c8D2a9d8Cb2)

Sky-governance exposure note: Spark Lend is a Sky sub-DAO. Roughly 56% of yvUSDT-1's debt sits in Spark USDT Lender, which is administered through Sky / Spark governance. This is a Sky-governance dependency but not a USDS-peg or USDS-collateral dependency — yvUSDT-1 is materially less Sky-coupled than yvUSDC-1 / yvUSDS-1 / yvDAI-1, but not fully Sky-independent.

Strategy Protocol Dependencies (current allocation)

Protocol	Strategy	Allocation	Notes
Morpho	MetaMorpho Vault (ymv-USDT)	43.94%	Yearn-operated MetaMorpho vault; governed by Yearn Security (4-of-7) with 3-day timelock; curator is a 2-of-3 Safe overlapping Brain/Security signers; guardian is Daddy (6-of-9)
Spark	Spark USDT Lender	56.06%	Sky sub-DAO; audited stack (ChainSecurity, Cantina); new strategy instance activated June 29, 2026

The current debt is split ~44/56 across two ecosystems (Morpho, Spark). Both have multi-year USDT track records with no significant principal-loss events. The mix is two-venue concentrated — ~56% allocation to a single Sky-governed venue is higher than the ~46% in the May 2026 snapshot and warrants continued monitoring. The Morpho leg is now through a Yearn-operated MetaMorpho vault rather than a third-party curator.

Audits and Due Diligence Disclosures

Yearn V3 Core Audits

Auditor	Date	Scope	Report
Statemind	May 2, 2024	V3 Vaults (v3.0.0)	PDF
ChainSecurity	May 4, 2024	V3 Vaults + Tokenized Strategy (v3.0.0)	2 PDFs
yAcademy	Jun 2024	V3 Vaults (v3.0.1)	PDF

Underlying Protocol Audits (active and queued strategies)

Underlying	Audits	Notes
Morpho	25+ audits across Trail of Bits, Spearbit, OpenZeppelin, ChainSecurity, Certora; formal verification	Blue-chip, $6.6B+ TVL; MetaMorpho vault source verified on Etherscan
Spark (USDT lender)	ChainSecurity, Cantina (Spark Lend / SparkDAO)	Sub-DAO of Sky; new SparkLender strategy source verified on Etherscan

Strategy Review Process

All strategies pass through Yearn's 12-metric risk-scoring framework (RISK_FRAMEWORK.md). yvUSDT-1 is registered as Category 1 in the Role Manager (getCategory(vault) == 1), the strictest tier.

Bug Bounty

• Yearn (Immunefi): active, $200,000 max payout (Critical). https://immunefi.com/bounty/yearnfinance/
• Yearn (Sherlock): also listed at https://audits.sherlock.xyz/bug-bounties/30
• Morpho (Cantina): active, $2,500,000 max payout (Critical). https://cantina.xyz/bounties/35a5f0a1-2ffd-432c-8f3b-77d169add8c3
• Safe Harbor (SEAL): Yearn is not listed on the SEAL Safe Harbor registry

On-Chain Complexity

Low. All funded strategies are direct USDT lend / compound with no conversion hops:

• MetaMorpho Vault → direct USDT deposit to a Yearn-operated Morpho MetaMorpho vault
• Spark USDT Lender → direct supply to Spark Lend USDT market
• No leverage, no looping, no cross-chain
• Standard ERC-4626 throughout
• Vault is immutable

Historical Track Record

• Vault deployed: July 23, 2024 (deployment tx) — ~23.6 months in production
• TVL: 7,229,374.54 USDT (~$7.23M) — well within the $50M deposit limit
• PPS trend: 1.000000 → 1.086177 (~8.62% cumulative return, ~4.4% annualized)
• Security incidents: None known for this vault or for the Yearn V3 framework
• Strategy history: seven strategies have been queued historically. Five have been revoked. Between May and July 2026, all three strategies active in the May report (Spark USDT Lender, Morpho Gauntlet USDT Prime, Morpho Steakhouse USDT) were revoked and replaced by two new strategies: a Yearn-operated MetaMorpho vault (ymv-USDT, activated May 10, 2026) and a new Spark USDT Lender instance (activated June 29, 2026)
• Yearn V3 track record: V3 framework live since May 2024 (~26 months). No V3 vault exploits

Yearn protocol TVL: ~$147M total across all chains (DeFiLlama, July 2026).

Underlying USDT lending market track records: Spark Lend and Morpho both have multi-year track records on USDT markets with no significant principal-loss events.

Funds Management

yvUSDT-1 is 100% deployed at the snapshot, split ~44/56 between a Yearn-operated MetaMorpho vault (ymv-USDT) and a Spark USDT Lender.

Current State (snapshot)

• Total Assets: 7,229,374.54 USDT
• Total Debt: 7,228,870.58 USDT (~99.99% deployed; ~$503 floating P&L)
• Total Idle: 0
• Capital utilization: ~99.99%

ERC-4626 redemptions settle by unwinding strategy positions in queue order — atomic from the user's perspective as long as the underlying lending markets have available liquidity (Spark Lend and Morpho USDT markets are both deep multi-million-USDT venues).

Active Strategies

Strategy	Allocation	Mechanic	Risk profile
MetaMorpho Vault (ymv-USDT)	43.94%	USDT deposit to Yearn-operated MetaMorpho vault on Morpho	Governed by Yearn Security (4-of-7), 3-day timelock, 2-of-3 curator Safe
Spark USDT Lender	56.06%	Direct supply to Spark Lend USDT market	Sky sub-DAO, ChainSecurity / Cantina audits; new instance June 2026

Both strategies are simple lend / compound patterns with no leverage, no conversion hops, and no cross-chain. The MetaMorpho vault introduces an additional governance layer (owner, curator, guardian, timelock) that is absent from the prior third-party curated Morpho vaults.

Accessibility

• Deposits: Permissionless ERC-4626. Subject to 50M USDT deposit limit
• Withdrawals: ERC-4626. Strategy unwind through Spark + Morpho USDT markets (both deep)
• No cooldown or lock period
• Fees: 0% management, 10% performance
• Profit unlock: 10 days

Collateralization

• ~99.99% USDT backing — held through MetaMorpho vault on Morpho and Spark Lend USDT market positions
• Collateral quality: USDT is the largest stablecoin by market cap. Centrally-issued by Tether
• No leverage
• Redemption: atomic for normal sizes; very large redemptions depend on MetaMorpho vault liquidity and Spark market utilization at the moment of withdrawal

The collateral quality is the union of the Yearn-operated MetaMorpho vault and Spark Lend USDT market quality — both are blue-chip USDT venues with multi-year clean track records.

Provability

• PPS: ERC-4626, fully algorithmic
• Strategy totalAssets(): reads the underlying lending position balance on-chain in both Spark and Morpho
• Profit / loss reporting: keepers via process_report(), profits unlock over 10 days

Liquidity Risk

Exit pipeline: ERC-4626 withdraw → strategy withdraw → underlying lending market withdrawal (MetaMorpho vault on Morpho or Spark Lend USDT market).

• Underlying liquidity: Spark Lend USDT and Morpho MetaMorpho vault are both multi-million-dollar venues with healthy utilization headroom; ~$4.1M (Spark) and ~$3.2M (Morpho) here are small fractions of either venue's free liquidity
• Same-asset: USDT-denominated share token — no price-divergence risk
• No DEX liquidity needed — exits via the lending protocol's own redemption mechanics
• No withdrawal queue or cooldown — atomic redemption for normal sizes (MetaMorpho vault has a 3-day timelock on parameter changes but redemptions are atomic)
• Deposit limit: 50M USDT cap vs $7.23M TVL (room for +591%)

The two-ecosystem split (~44% Morpho / ~56% Spark) means a liquidity squeeze in one venue can be partially absorbed by the other (subject to queue order and the user's withdraw size).

Centralization & Control Risks

Governance

Position	Address	Threshold	Roles on Vault
Daddy (ySafe)	0xFEB4acf3df3cDEA7399794D0869ef76A6EfAff52	6-of-9	12 of 14 vault roles
Brain	0x16388463d60FFE0661Cf7F1f31a7D658aC790ff7	3-of-8	QUEUE, REPORTING, DEBT, MAX_DEBT, DEPOSIT_LIMIT, WITHDRAW_LIMIT, PROFIT_UNLOCK, DEBT_PURCHASER, EMERGENCY
Security	0xe5e2Baf96198c56380dDD5E992D7d1ADa0e989c0	4-of-7	DEBT, MAX_DEBT, EMERGENCY
Strategy Manager (Timelock)	0x88Ba032be87d5EF1fbE87336b7090767F367BF73	7-day delay	ADD_STRATEGY, REVOKE_STRATEGY, FORCE_REVOKE, ACCOUNTANT, MAX_DEBT
Keeper	0x604e586F17cE106B64185A7a0d2c1Da5bAce711E	Bot	REPORTING only
Debt Allocator	0x1e9eB053228B1156831759401dE0E115356b8671	Bot	REPORTING + DEBT_MANAGER

ySafe 6-of-9 signers include publicly known DeFi contributors — see Yearn Multisig Info.

Properties:

1. No EOA holds vault roles directly
2. Strategy additions and accountant changes pass through 7-day timelock
3. Self-governed timelock — TIMELOCK_ADMIN belongs to the timelock itself
4. Vault contract is immutable — Vyper minimal proxy
5. Same governance pattern across 37+ vaults

Programmability

• PPS: ERC-4626, fully algorithmic
• Vault operations: permissionless deposit / withdraw on-chain
• Strategy reporting: automated via keeper (when strategies are funded)
• Debt allocation: Debt Allocator (automated) + Brain (manual) — currently 0 deployed
• Off-chain inputs: none

External Dependencies

Dependency	Criticality	Notes
USDT (Tether)	Critical (underlying asset)	Centrally issued; relies on Tether's operational and reserve integrity
Spark Lend	High (~56% of debt)	Sky sub-DAO; Spark admin keys live under Sky governance
Morpho	High (~44% of debt)	Morpho protocol $6.6B+ TVL; MetaMorpho vault governed by Yearn Security with 3-day timelock + 2-of-3 curator Safe
Sky governance	Indirect via Spark	Spark Lend admin sits under Sky; not an independent venue
MetaMorpho curator	Indirect, internal	2-of-3 Safe with overlapping Brain/Security signers; can adjust vault parameters within timelock constraints

Dependency quality: the deployed mix is two blue-chip ecosystems split ~44/56 (Morpho + Spark). ~56% of debt sits behind Sky-governed infrastructure — an increase from ~46% in the May 2026 snapshot. Materially less Sky-coupled than yvUSDC-1 / yvUSDS-1 / yvDAI-1 (which carry direct USDS exposure) but not fully Sky-independent. The Morpho leg is now through a Yearn-operated MetaMorpho vault rather than third-party curated vaults, which internalizes curator risk but adds the vault's own governance surface (owner, curator, guardian, timelock).

Operational Risk

• Team: Yearn Finance — established 2020, public contributors, named multisig signers
• Vault management: Standard Yearn V3 Role Manager pattern shared across 37+ vaults
• Documentation: Comprehensive Yearn V3 documentation. Strategy code verified on Etherscan
• Legal: Yearn BORG via YIP-87
• Incident response: 4 historical V1 events handled. V3 framework not yet stress-tested by an exploit
• V3 immutability: vault cannot be upgraded
• Operational history:
  • Late April 2026: 100%-idle posture, precautionary deallocation following the rsETH bridge exploit (per Yearn team, unverified attribution)
  • May 2026: Redeployment into Spark + Morpho Gauntlet (~46/54 split); Fluid and Aave V3 strategies revoked
  • May–July 2026: Full strategy-queue replacement — all three remaining strategies revoked, replaced by a Yearn-operated MetaMorpho vault (activated May 10, 2026) and a new Spark USDT Lender (activated June 29, 2026). Rationale for the full replacement rather than incremental changes has not been independently verified
  • The sequence demonstrates active debt management capability: the operations multisigs can pull, revoke, and redeploy across entirely new strategy sets

Monitoring

Existing Monitoring Infrastructure

Yearn maintains the monitoring repository with active alerting. yvUSDT-1 is in the monitored vault list:

• Large flow alerts (protocols/yearn/alert_large_flows.py) — runs hourly via the automation scheduler
• Endorsed vault check (protocols/yearn/check_endorsed.py) — daily
• Timelock monitoring (protocols/timelock/timelock_alerts.py)

Key Contracts

Contract	Address	Monitor
yvUSDT-1 Vault	0x310B7Ea7475A0B449Cfd73bE81522F1B88eFAFaa	PPS (convertToAssets(1e6)), totalAssets(), totalDebt(), totalIdle(), Deposit / Withdraw events
Each active USDT strategy	(2 active addresses above)	totalAssets(), current_debt, isShutdown(), keeper report frequency
MetaMorpho vault (ymv-USDT)	0x0963232eB842BAF53E8e517691f81745C1F228a0	totalAssets(), owner(), curator(), guardian(), timelock(), supplyQueue() market list
ySafe (Daddy)	0xFEB4acf3df3cDEA7399794D0869ef76A6EfAff52	Signer / threshold changes
Accountant	0x5A74Cb32D36f2f517DB6f7b0A0591e09b22cDE69	Fee changes

Critical Events to Monitor

• Allocation drift — currently ~44/56 Morpho/Spark; a drift toward >75% in one venue should trigger reassessment of the dependency subscore
• Strategy current_debt changes — DebtUpdated events on the vault
• Strategy additions / removals — StrategyChanged events (new strategies pass through 7-day timelock; further revocations are operational signals)
• MetaMorpho vault governance changes — owner(), curator(), guardian(), or timelock changes on the ymv-USDT vault
• Emergency actions (Shutdown)
• ySafe / Brain / Security signer or threshold changes
• PPS decrease — should only increase outside of explicit loss events
• Sky / Spark governance events — Spark Lend admin actions can affect ~56% of yvUSDT-1's debt
• USDT-specific: Tether-side issues (peg deviation, attestation reports, blacklisting events)

Monitoring Functions

Function	Contract	Purpose	Frequency
convertToAssets(1e6)	Vault	PPS tracking	Every 6 hours
totalAssets()	Vault	Total TVL	Daily
totalDebt() / totalIdle()	Vault	Capital deployment ratio — currently 100% deployed	Daily
strategies(address)	Vault	Per-strategy debt, last report time, activation (revocations show activation = 0)	Daily
get_default_queue()	Vault	Withdrawal queue composition (currently 2 strategies)	Weekly
getThreshold() / getOwners()	ySafe	Governance integrity	Weekly
getMinDelay()	ySafe	Delay change detection	Weekly

Reassessment Triggers

• Time-based: Reassess in 6 months (January 2027) or annually
• TVL-based: Reassess if TVL exceeds $25M or changes by ±50%
• rsETH-related context: if any new strategy is added that takes direct or indirect rsETH exposure, full re-review of the dependency subscore
• Strategy posture:
  • if a USDS-denominated strategy is later added to yvUSDT-1, the partial Sky-coupling becomes a peg dependency — re-evaluate dependency and concentration scores against the broader risk-1 stable stack
  • if either venue's allocation drifts above ~75% of deployed funds, re-evaluate the dependency / liquidity scores
  • the MetaMorpho vault's governance parameters (owner, curator, guardian, timelock) are new; any change to these should trigger reassessment
  • if any further strategy revocations or replacements occur, investigate the rationale
• Underlying-protocol incidents: any major incident at Spark Lend or Morpho USDT markets — full re-review
• USDT-specific:
  • sustained Tether peg deviation
  • Tether reserve attestation issues
  • significant blacklisting / freezing events
• Governance-based: ySafe / Brain / Security signer or threshold changes; any change to the timelock delay (would itself require 7 days)

---

Appendix: Contract Architecture

┌─────────────────────────────────────────────────────────────────────┐
│                         VAULT LAYER                                  │
│                                                                      │
│  ┌───────────────────────┐                                          │
│  │  yvUSDT-1 (v3.0.2)   │                                          │
│  │  ERC-4626, immutable  │                                          │
│  │  EIP-1167 min proxy   │                                          │
│  │  0x310B…FAaa          │                                          │
│  │                       │                                          │
│  │  $7.23M USDT TVL      │                                          │
│  │  ~99.99% deployed     │                                          │
│  │  totalDebt = $7.23M   │                                          │
│  │  totalIdle = 0        │                                          │
│  └───────────┬───────────┘                                          │
│              │                                                       │
│      ┌───────┴────────┐                                             │
│      ▼                ▼                                             │
│  MetaMorpho Vault  Spark USDT Lender                                │
│  (ymv-USDT)        4.05M (56.06%)                                   │
│  3.18M (43.94%)    Sky sub-DAO                                      │
│  Morpho protocol                                                     │
│                                                                      │
│  MetaMorpho governance:                                              │
│   - Owner: Yearn Security (4-of-7)                                  │
│   - Curator: 2-of-3 Safe                                            │
│   - Guardian: Daddy (6-of-9)                                        │
│   - Timelock: 3 days                                                │
│                                                                      │
│  All previously-queued strategies revoked (activation = 0):          │
│   - Spark USDT Lender (old, 0xED48…9400B)                           │
│   - Morpho Gauntlet USDT Prime (0x6D29…849F)                        │
│   - Morpho Steakhouse USDT (0x0a4e…45c5)                            │
│   - USDT Fluid Lender (0x4Bd0…8A72)                                 │
│   - Aave V3 USDT Lender (0x2799…8Cb2)                               │
└──────────────────────────────────────────────────────────────────────┘

The vault is now ~44/56 across two ecosystems. ~56% sits behind Sky-governed
infrastructure (Spark Lend), up from ~46% in May 2026. The Morpho leg is through
a Yearn-operated MetaMorpho vault with its own governance surface (owner,
curator, guardian, timelock) rather than a third-party curated vault.

Appendix: TimelockController Role Structure

TimelockController 0x88Ba032be87d5EF1fbE87336b7090767F367BF73 — same timelock used by 37+ Yearn V3 vaults including all six mainnet risk-1 vaults. getMinDelay() = 604800 (7 days).

Role	Holder	Type	Notes
DEFAULT_ADMIN	No holder	—	Never granted (admin = address(0))
TIMELOCK_ADMIN	Timelock itself	Contract	Self-governed
PROPOSER	Daddy/ySafe	6-of-9 Safe	Sole proposer
EXECUTOR	Daddy/ySafe	6-of-9 Safe	Direct execution
EXECUTOR	TimelockExecutor 0xf8f60bf9456a6e0141149db2dd6f02c60da5779b	Contract	Wrapper: Brain (3/8) + deployer EOA can call execute() through it
CANCELLER	Daddy/ySafe	6-of-9 Safe	Cancel pending proposals
CANCELLER	Brain	3-of-8 Safe	Cancel pending proposals

To shorten the delay, Daddy 6/9 must propose updateDelay(), wait 7 days during which Brain or Daddy can cancel, then execute. DEFAULT_ADMIN was never granted, so no party can self-grant PROPOSER or TIMELOCK_ADMIN to skip the flow.