Mantle Launches Non-Custodial RWA Vault to Bridge CeFi Yields to DeFi

$200 million crossed on Bybit, then the product opened onchain. That is the trajectory of Mantle Vault, which previously sat inside Bybit Earn and has now been re-issued as a non-custodial DeFi vault on Mantle, routed through Fluxion and built on infrastructure from CIAN and Grove. As reported by crypto.news, the August 25 launch accepts USDC and USDT0 deposits and targets an APY of up to 6.5%.

Vault Architecture

Depositors enter through Fluxion, which serves as the entry interface. CIAN packages the underlying strategy and posts positions and transactions onchain for direct verification. Grove connects the vault to the Sky ecosystem and routes stablecoin liquidity into sUSDS, the savings-bearing version of Sky's USDS stablecoin. The structure is explicitly non-leveraged, which removes a specific liquidation channel but does not eliminate counterparty or governance exposure.

The mechanics translate to three layers:

• Entry: USDC or USDT0 into Fluxion's vault contract.
• Routing: CIAN-managed strategy infrastructure, visible onchain.
• Yield source: sUSDS, the savings rate product of Sky.

Each layer introduces a distinct trust assumption: the vault code, the strategy manager, and the Sky governance process that sets the underlying savings rate.

Underlying Return and the Promotional Layer

The base return flows from sUSDS. An August 6 RWA deposit report cited sUSDS supply at 4.61 billion with a savings rate of 3.52% at the time of review. That figure is not static. Sky governance retains the authority to adjust the rate, which means the depositor's underlying yield is variable rather than contractual.

On top of the base return, Mantle has layered campaign incentives: Fluxion Points and an allocation of 5.14 million GROVE tokens. These are promotional components, not cash yield. Their realized value depends on campaign rules, participation depth, and token market price. We flag this as a separation point. The headline 6.5% target APY is a composite figure that includes the variable sUSDS rate plus a token incentive component whose conversion economics are not guaranteed.

Risk Profile

The non-custodial framing removes the centralized custodian counterparty, but it does not remove the other vectors. We see four primary risk channels:

1. Smart contract failure across the Fluxion vault, the CIAN strategy layer, and the Grove integration with Sky.

2. Stablecoin depeg on USDC or USDT0.

3. Liquidity conditions affecting exit from the vault or from sUSDS itself.

4. Governance risk — Sky's savings rate can change by vote, compressing yield without notice.

The December 2025 Bybit product and its successor vault share CIAN's strategy infrastructure, which provides some continuity. That said, a CeFi distribution and a DeFi deployment are not identical code paths, and we treat the DeFi version as a separate audit surface.

What to Verify Before Depositing

For readers considering capital allocation, we recommend three checks:

• Confirm the live sUSDS savings rate at the moment of deposit. A 3.52% base rate plus promotional tokens does not mechanically reach 6.5% unless the token component clears at stated value.
• Review the vault contract on a block explorer for admin keys, upgradeability, and pause functions. The CIAN component is described as onchain-visible, which we read as a positive signal for transparency but not as a substitute for code review.
• Map the withdrawal path. Promotional campaigns frequently carry vesting or claim mechanics that delay realized value.

The risk-to-reward profile hinges on a single variable: whether the Sky savings rate holds. If it stays near current levels and the GROVE token component retains market value, the composite yield is competitive with comparable structured products. If governance compresses the rate, the promotional layer becomes the entire return, and promotional layers are the first line items that erode under yield compression. We rate the structure as conditionally viable: acceptable for capital comfortable with the four risk channels listed above, insufficient for capital that requires a fixed contractual return.