sUSD

sUSD was Synthetix's SNX-backed synthetic dollar; SIP-420 removed the peg defense and, after a year-long depeg, it was frozen and retired via SIP-423.

Frozen Archive

USD-Pegged Crypto-Backed Centralized-Dependent

03 Dec 2018

Price

N/A

Observed price unavailable

Market cap

$16.30M

+0.06% 24h

Supply

— sUSD

— 7d

DEWS

Peg

Liq53as of 2026-10-24

30d Excess

Price

N/A

Observed price unavailable

Market cap

$16.30M

+0.06% 24H

Supply

— sUSD

— 7D

30d Excess

MechanismCrypto CDPMintingGoverned CDP FreezeNoChains4 JurisdictionNot disclosed Issued2018

MintingGoverned CDP FreezeNoChains4 JurisdictionNot disclosed Issued2018

Case studysUSD and SIP-420: the depeg a governance vote choseDied

Algorithmic Failure

“Saved the protocol at the cost of its dollar”

sUSD archived 2026-06-26

Launched in 2018, sUSD was Synthetix's flagship synthetic dollar, an overcollateralized stablecoin minted against staked SNX. Its peg held for years on a single reflex: whenever sUSD slipped below $1, stakers bought it back at a discount to repay their debt at par. SIP-420 (April 2025) dismantled that reflex, cutting the required collateral ratio from 750% to 200% and pooling debt collectively. Minting got cheap, but no individual was left with a reason to defend the dollar. sUSD fell to $0.68 within weeks and never recovered, drifting below peg for over a year as supply bled from a ~$329M peak toward a functionally insolvent tail near $0.23. In June 2026 Synthetix governance stopped repairing it and passed SIP-423: the contract was frozen, a holder snapshot taken, and sUSD made permanently non-transferable, with remaining holders entitled to 4 SNX per sUSD, locked for one year and then vested over a second year from the freeze. Unclaimed receipts expire worthless after six months. sUSD held in LP pools, vaults or other deposit contracts cannot be recovered directly; those holders go through a separate Treasury claims process using their deposit or LP receipt tokens, evaluated case by case.

SIP-423: sUSD wind-down (Synthetix SIPs)View on cemetery →

Retired Below Par

Synthetix's sUSD was DeFi's original synthetic dollar, minted against staked SNX from 2018. Its peg rested on one reflex: when sUSD slipped below $1, stakers bought it at a discount to repay their debt at par. SIP-420 in April 2025 dismantled that reflex by cutting the collateral ratio from 750% to 200% and pooling debt, so minting got cheaper while no individual staker had a reason to defend the dollar. sUSD fell to about $0.68 within weeks and never recovered. Treasury and SLP-vault activity worked as peg defense rather than backing, and it never brought sUSD back to par. In June 2026 governance chose conversion over repair and passed SIP-423: the contract was frozen, a holder snapshot was taken, and sUSD became permanently non-transferable. Snapshot holders are entitled to 4 SNX per sUSD, locked for one year and then vested over a second, so compensation carries up to two years of SNX price exposure. Unclaimed receipts expire worthless after six months. sUSD left in LP pools or vaults cannot be recovered directly; those holders must claim through a separate Treasury process using their deposit or LP receipt tokens, assessed case by case. Pharos froze its tracking on June 26, 2026.

Updated 2026-10-19 · AI summary · drafted by claude-opus-5-5 · facts as of 2026-10-19

AI policy

CeFi-Dependent|Compare

Depeg Early Warning

Not applicablefrozen archive

Control evidence

sUSD

Mint Authority

Users mint sUSD against collateral under governance, controlled by a contract; admin powers are only partly bounded.

Confidence: VerifiedControl posture: Multisig controlled

Control map

IssuerGoverned CDP

ControlsDirect minter×2Minter adminGovernor Safe4/7

SupplysUSDPartially bounded admin

Scoring breakdown

Derived posture Unknown

Component score Loading

The current Safety Score publication is loading; reviewed mint authority evidence is shown below.

Primary controls (4)

sUSD Ethereum legacy proxy (RetiredSynthsUSD target)
Direct minter / Contract
ethereum / 0x57ab1e...6d5f51
MintUpgrade-only
The current RetiredSynthsUSD target exposes no issue or mint path and totalSupply() is zero, but the proxy owner can call setTarget and install new mint-critical logic, so the native issuance bound can be reopened.
Synthetix V3 Core Proxy
Minter admin / Contract
ethereum / 0xffffff...875847
MintCap-limited
V3 minting is bounded by Synthetix debt-pool collateralization and market configuration, which the same governance Safe can update.
Synthetix governance multisig (4-of-7 Gnosis Safe)
Governor / Safe
ethereum / 0xeB3107...917769
MintParameter-onlySetupSafe, 4/7 thresholdSafe modules/guardNo modules or guards detected
sUSD Optimism legacy proxy (RetiredSynthsUSD target)
Direct minter / Contract
optimism / 0x8c6f28...1ec8d9
MintUpgrade-only
The current RetiredSynthsUSD target exposes no issue or mint path and totalSupply() is zero, but the Optimism proxy owner relay can authorize setTarget through the Ethereum OwnerRelay and Safe, so native issuance logic can be reopened.

Review notes & sources (17)

Synthetix legacy sUSD has reviewed native-issuance deployments on Ethereum and Optimism, both now retired under SIP-423. Their terminal RetiredSynthsUSD targets have zero supply and no direct issue path, but proxy replacement remains a native issuance control; the Ethereum V3 Core owner and shared 4-of-7 Safe remain in Mint Authority. Arbitrum and Fantom representations are assessed only under bridgeRouteRisk.

Control posture

Material control is classified as requiring approval from a defined group of signers through a multisignature account.

CeFi-Dependent is the broader governance classification. Control posture describes more precisely where operational authority sits.

Control posture is not a Safety Score input. Economic Control is scored from the reviewed mint authority, oracle and bridge evidence.

Reviewed 2026-08-16

sUSD

Standard external

Collateral is priced from a standard external feed.

Oracle review: Verified

Pricing path

SourcesUndisclosed

AggregatorStandard external

ConsumerLiquidation engine

Review notes & sources (2)

Synthetix sUSD historically relies on Chainlink-decentralized price feeds for synth pricing, with no stronger failover tier verified here.

Synthetix Chainlink integration

Reviewed 2026-06-12

sUSD

Mixed tiers

4 routes on 4 chains, 4 tiers, largest issuer burn & mint (1); weakest opaque / unknown. No third-party routes.

Confidence: Verified

Routes by chain (4)

Equal widths, supply split unavailable

Review notes & sources (8)

The review rates the inventory external validator network overall, better than its weakest listed route (opaque / unknown).

Legacy Synthetix sUSD has native-issuance deployments on Ethereum and Optimism, both suspended and retired under SIP-423. Bridge Risk separately covers the historical Ethereum↔Optimism lock-mint route, the Arbitrum canonical-rollup StandardArbERC20 gateway with its UpgradeExecutor-owned ProxyAdmin, and the Fantom AnySwap/Multichain representation whose EOA-controlled Swapin mint remains arbitrary. Synthetix Teleporter and CCIP material is V3-only and is not treated as a durable bridge route for this retired V2x token.

Reviewed 2026-08-16

sUSD

Not freezable

Under the reviewed deployment-materiality scope, no issuer freeze, seizure, or holder blacklist path sets the verdict. Peripheral deployment controls, if any, are described in the review notes.

Rationale only

Power and scope

PowerNot freezable

Review notes & sources (2)

Inferred review updated: SUSD has no resolved direct holder freeze surface, and its matched upstream reserve exposure is below the strict >50% threshold, so it resolves to No rather than Upstream.

No public source. Resolved from Pharos stablecoin metadata by the blacklistability resolver under the v3.9973 majority-threshold upstream policy; no separate manual override source is attached.

Reviewed 2026-05-12

Key links

Website Twitter Docs

Contracts

4 deployments tracked across Ethereum, Optimism, Fantom, and Arbitrum.

Primary contract

Ethereum

0x57ab...5f51

View on Ethereum explorer

Ethereum0x57ab...5f51

Optimism0x8c6f...c8d9

Fantom0x0e16...518e

Arbitrum0xa970...2f95

Supply & Liquidity

Data frozen on 2026-06-26. Pharos no longer collects new metrics for this asset.

History

Data frozen on 2026-06-26. Pharos no longer collects new metrics for this asset.

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Case studysUSD and SIP-420: the depeg a governance vote chose

Peers

DAI

Taxonomy

All US Dollar stablecoins CeFi-Dependent stablecoins Crypto-Collateralized stablecoins

Trackers

Stablecoin safety scores DEX liquidity rankings Depeg tracker See all CDP stablecoins

Actions

Open sUSD in live compare Browse stablecoin comparisons Read the daily digest Use the Pharos API

Profile

sUSD profile facts

sUSD (sUSD) static profile: governance model CeFi-Dependent; backing model Crypto-Collateralized; peg US Dollar.

CeFi-Dependent Crypto-Collateralized US Dollar

Other coins using the sUSD ticker

Solayer USD (sUSD) · Active · US Dollar. Solayer sUSD is a Solana Token-2022 interest-bearing stablecoin backed by U.S. T-bill exposure and RWA partner products.
Staked USD Coin (sUSD) · Active · US Dollar. HedgeCore sUSD is a soul-bound BSC yield wrapper minted from USDC and routed through Venus lending.

Collateral: SNX, ETH, and USDC/stataUSDC via Synthetix V3; direct SNX minting deprecated in 2025. Pooled SNX remained the primary legacy backing, while delta-neutral basis-trade vaults, protocol treasury activity, and buybacks functioned as peg-defense and recovery layers rather than the main reserve base.
Peg mechanism: Overcollateralization via C-ratio (200%+); V3 expanded collateral to SNX, ETH, USDC/stataUSDC; sUSD minting against SNX deprecated in 2025; peg sustained via SLP Vault basis-trade strategy and protocol fee buybacks
Jurisdiction: Not disclosed in the static profile.
Proof of reserves: No proof-of-reserves entry in the static profile.
Contracts: 4 deployments tracked across Ethereum, Optimism, Fantom, and Arbitrum.

Source: Pharos registry profile fields. This inactive record does not participate in current live monitoring.

sUSD quick answers

What is sUSD?

sUSD was Synthetix's SNX-backed synthetic dollar; SIP-420 removed the peg defense and, after a year-long depeg, it was frozen and retired via SIP-423. The static profile records its US Dollar peg mechanism as: Overcollateralization via C-ratio (200%+); V3 expanded collateral to SNX, ETH, USDC/stataUSDC; sUSD minting against SNX deprecated in 2025; peg sustained via SLP Vault basis-trade strategy and protocol fee buybacks.

Is sUSD safe?

sUSD is a frozen Pharos archive, not a current safety endorsement. The archived static profile records a CeFi-Dependent governance model, Crypto-Collateralized backing, curated reserve profile, and notes that no direct freeze-control path sets the verdict under the reviewed deployment-materiality scope.

What backs sUSD?

The archived Pharos profile records sUSD's reserves as 50% SNX (via legacy V2 420 pool, 200% C-ratio), 25% USDC / stataUSDC (V3 Base pool collateral), 15% ETH and LSTs (V3 multi-collateral), and 1 smaller holding. Reserve evidence: curated reserve profile. Pharos classifies the backing as Crypto-Collateralized.

Can sUSD be frozen or blacklisted?

Based on tracked contract metadata and blacklist coverage, no direct freeze-control path sets the verdict under the reviewed deployment-materiality scope. sUSD is a frozen Pharos archive; the recorded history below is read-only.