Class rule for yield aggregators

Ketju does not approve this kind of structure, whatever the protocol’s quality, and makes no finding against the protocol itself. A class rule never chooses a client position or amount.

Scope

Vaults, aggregators and vaults of vaults in which a manager, a governance vote or an automated allocator can move client assets among strategies or venues after deposit.

The rule

Ketju does not approve a vault when the advisor cannot identify and monitor the underlying venues or apply the client’s own limits over time. When another allocator keeps choosing the venues, that allocator decides what the client holds and who controls it.

When the rule applies

• An authorized party or algorithm can change the underlying venues after the client deposits.
• The client cannot enforce a fixed allowlist and per-venue limits that match the advisor’s mandate.

Research

How it works

A depositor receives vault shares while an allocator assigns capital to one or more strategies. The share price adds up gains and losses across a portfolio whose weights can change with no new client transaction. An ERC-4626 interface standardizes the accounting, but it does not limit what an authorized vault may own.

Who controls it

Vault roles may add or remove strategies, change allocations, set queues, report losses or use emergency shutdown powers. Those controls can be well designed and audited. The problem is that the client’s actual exposure, and the party that decides it, no longer match the protocols the advisor approved.

Losses and incidents

A vault takes on the contract, oracle, liquidity, governance and economic failures of every active strategy, plus integration and accounting risk in the allocator itself. Spreading deposits can reduce a single loss. It can also hide exposures that move together, or send money into a protocol that Ketju does not approve.

Withdrawals

A redemption of shares depends on the vault’s buffer and on the underlying strategies returning funds in order. Withdrawal queues and unrealized losses can make the displayed share value differ from what a holder actually receives during stress.

Comparison

Direct positions in approved venues let the advisor see exactly what the client owns and apply the client’s own limits, without a research memo choosing an amount. Ketju may review a wrapper on its own if the wrapper cannot change its exposures, because it then makes no continuing allocation decision.

Review triggers

• The vault enforces an immutable or client-specific allowlist and limits that cover only approved venues.
• Position-level holdings, allocations, realized losses and the liquidity available for withdrawal become continuously available, and anyone can verify that the vault enforces the mandate.

Sources

Each source shows its type, the date Ketju accessed it, and the claims it supports. “Primary” means first-hand or governing material; it does not mean that Ketju verified the source independently.

• Yearn YIP-75: V3 launch and architecture · primary · accessed 2026-08-14
  Supports: allocator, strategies, governance
• Yearn VaultV3 contract · primary · accessed 2026-08-14
  Supports: roles, strategy debt, withdrawal queue
• ChainSecurity: Yearn V3 Vaults audit · secondary · accessed 2026-08-14
  Supports: contract controls, loss accounting, security review

Memos under this rule

Each memo listed applies this version of the rule. The depth of research on each protocol varies by memo; where a memo has named sources and fuller research, the memo shows them.