[RFC] Onboarding infiniFi siUSD into Summer.fi USDC mainnet vault

General Discussion Request for Comment [RFCs]
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Author: @Valbpereira (@Val_bpereira on x)

Submission Date: 1 August 2025

Summary

Onboarding siUSD (infiniFi staked asset) to be allocated for USDC mainnet vault

infiniFi automates borrow-short, lend-long asset management to achieve superior returns on any on-chain or off-chain asset. Same quality assets that you already trust. Higher returns. No leverage.

How does infiniFi work:

infiniFi is a decentralized fractional reserve staking system designed to improve financial stability and capital efficiency while aligning depositor incentives. It allows users to mint the iUSD stablecoin which is backed by a basket of liquid and duration based collaterals like sUSDe and Pendle PTs. Depositors can choose to stake for siUSD and remain liquid or take on duration to earn higher returns, enabling automated maturity laddering of reserves and reducing duration mismatch risks—challenges inherent in traditional banking.

Key features of siUSD include:

  • Fractional Reserve Design: Achieves higher yield across depositor segments by combining liquid and locked capital into duration-matched strategies

  • Senior Risk Protection: Users who take on duration by locking their iUSD act as the junior capital protecting siUSD holders from potential losses.

  • Yield Optimization: Liquid deposits earn top DeFi rates, while locked positions gain amplified returns

  • Blockchain Transparency: Fully on-chain and governed by smart contracts, ensuring transparency and trustlessness

siUSD represents the staked version of iUSD, designed to capture native senior tranche yield and additional protocol incentives while maintaining the stability characteristics of the underlying iUSD token.

Full transparency:

https://stats.infinifi.xyz

Main Risks

At infiniFi, security is a top priority. The protocol has undergone audits by leading firms including Spearbit, Cantina, and Certora (formal verification), and continues to run multiple bug bounty programs to ensure robust protection.

View documentation: https://docs.infinifi.xyz/audits

Users may experience temporary illiquidity if there is a surge in simultaneous withdrawal requests. In such cases, immediate exits can still be made through secondary markets like Fluid, Curve, and Balancer. Alternatively, users can wait for capital deployed into illiquid yield strategies to mature and become liquid again. In the case of loss of protocol funds locked iUSD positions which are junior to siUSD will act as a buffer, needing to be completely wiped out before any senior tranche (siUSD) holders are affected.

Specifications

Token: siUSD

Network: Ethereum

Contract Address: 0xDBDC1Ef57537E34680B898E1FEBD3D68c7389bCB

Risk Level: Lower risk

1 Like
[SIP2.30] Add siUSD to Lower Risk USDC Vault
Lazy Summer Governance Recap [August 2025]
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Thanks for the proposal and welcome to the forum @Valbpereira!

siUSD’s seems promising for the USDC mainnet vault. Maybe there is some complexity around liquidity timing during high withdrawals, but risk buffers seem well structured. How long are the withdrawal queues?

Would love to hear thoughts from other @Recognized_Delegates on fit and from @BlockAnalitica about the risk level.

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In the event of higher-than-usual withdrawals, there’s a chance some users may face short-term delays *if the withdrawal demand exceeds liquid reserve buffer*. That said, exits are always possible via secondary markets like Fluid, Curve, or Balancer.

We intentionally ladder our illiquid strategies to maintain short-term flexibility [xx]% of capital can be accessed within 7 days, and another [xx]% within 14 days. https://stats.infinifi.xyz/

Withdrawals for siUSD are processed instantly under normal conditions. In extreme cases, timing may extend slightly, but we’ve built buffers and maturity staggering to minimize that risk.

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Thank you for your reply! Looking forward to thoughts of other @Recognized_Delegates!

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@Recognized_Delegates Would appreciate your thoughts on this.

@BlockAnalitica - also your thoughts too, I suspect the higher risk vault given the potential withdrawal queues etc.

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BA Labs supports the Infinifi siUSD asset onboarding to SummerFi as it essentially doesn’t bring exposure to any additional collateral assets based on the allocation breakdown of siUSD at the time of writing.

However, due to the liquidity mechanisms put in place, and general TVL level (~$75m) of Infinifi protocol, we suggest listing this ARK in a Higher Risk USDC Fleet on Mainnet due to potential withdrawal limits, depending on the SummerFi type of allocation to iUSD.

Considering the current “Instant Liquidity” available for SummerFi depositors of ~$68m, representing ~57% of the current TVL, we propose taking the senior tranche allocation within Infinifi (siUSD), as proposed above, to avoid secondary market exits and mitigate slashing risks the holders of liUSD are taking.

Pending the governance vote, BA Labs will provide details about proposed ARK parameters in timely manner below.

4 Likes
[SIP2.30] Add siUSD to Lower Risk USDC Vault
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Thank you for supporting the onboarding of siUSD. We appreciate the detailed assessment on liquidity and tranche allocation, and understand the reasoning behind placing siUSD within the Higher Risk USDC Fleet for now.

Could you please outline the next steps we should follow on our end to move this forward? We’ll make sure to coordinate accordingly and provide any additional data you may need ahead of the governance vote. @BlockAnalitica @chrisb @jensei

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happy to see that this RFC has made it into an SIP now posted here - [SIP 2.30] Add siUSD to Lower Risk USDC Vault.