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Fluid DEX

Rejected
Max sleeve
Reviewed
2026-08-14 · v1
Next review
2026-11-15
Chains
Ethereum · sovereign, Arbitrum One · hybrid, Base · hybrid, Polygon PoS · hybrid

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

Fluid DEX is an AMM where an LP position can double as loan collateral inside the wider Fluid system. It held about $315M across four chains at the 2026-08-14 survey. The collateral feature does not change the underlying market-making trade: smart collateral earns LP fees while securing debt, and smart debt can itself provide trading liquidity. This composes inventory loss, oracle and liquidation paths through Fluid’s shared Liquidity Layer. The amm-lp rule is dispositive before those added risks are underwritten; this is not an individual rejection of Fluid’s contracts.

The research file

The mechanism

Fluid DEX is built over Fluid’s central Liquidity Layer and integrates with its Vault borrowing system. Smart collateral allows pooled assets to earn swap fees while remaining collateral; smart debt lets borrowed balances provide DEX liquidity. The DEX combines v2- and v3-like pool configuration. LP inventory still changes as arbitrage trades, and leverage can turn relative-price movement into liquidation.

Control and operating record

A single Liquidity contract holds funds for Fluid protocols, while factories create fTokens, vaults and DEXes. That consolidation improves capital use and makes Liquidity Layer, oracle and authorized-protocol controls shared dependencies. Fluid publishes MixBytes and StateMind audits covering the DEX and wider architecture. Audit evidence is material, but this class memo does not verify every finding, deployment or pool.

The exit

An unlevered LP exit returns current pool inventory, not original quantities. If the position also backs a vault, collateral cannot be removed if doing so violates the required debt ratio; an unhealthy position can be liquidated. Shared-layer liquidity and a pool’s asset behavior therefore govern whether a nominally available exit is economically usable.

Why the class rule decides

Smart collateral improves capital efficiency but does not remove adverse inventory rebalancing; borrowing adds rather than substitutes risk. The amm-lp class rule therefore ends suitability analysis for this sleeve. A Fluid lending product with no LP exposure requires its own memo and can be assessed independently.

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.
Arbitrum OneApproved · limits hybrid a single sequencer orders >99% of transactions and admin keys can upgrade bridge contracts on a ~7-day timelock.
BaseApproved · limits hybrid Coinbase — one regulated US company — operates the only sequencer, and admin keys can upgrade bridge contracts within ~7 days.
Polygon PoSRejected hybrid a public validator set orders transactions, but a 5-of-9 multisig can instantly upgrade staking and canonical bridge contracts, while a 5-of-8 controls custom child tokens.
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