Since launching on Base on November 18, 2024, Spark has seen rapid adoption. In just three months, the circulating supply of sUSDS on Base surpassed $50M, peaking at $118M with over 650 wallets holding more than 100 sUSDS. This growth confirmed strong demand for on-chain yield and composable savings products.

Now, Spark is proud to announce that it is live on both Optimism’s OP Mainnet and Unichain, laying the liquidity foundation for the next phase of Ethereum’s evolution: the Superchain.

But this isn’t just another deployment. It’s a coordinated strategy in partnership with the Optimism Collective to make native interoperability real — turning the fragmented L2 landscape into a unified and composable financial system.

Based on the momentum and learnings from Base, Spark is ready to scale with the Superchain.

Spark has expanded to Optimism’s OP Mainnet and Unichain, bringing savings yield to USDC and USDS, and establishing foundational liquidity infrastructure through the Spark Liquidity Layer (SLL).

This deployment includes the launch of sUSDC and sUSDS. sUSDC is a yield-bearing representation of USDC. Users can directly deposit USDC into the USDC Savings Vault and receives sUSDC, which accrues yield based on the Sky Savings Rate (SSR), currently set at 4.5% by Sky governance. This rate reflects returns from over-collateralized DeFi loans and real-world investments. You can track it in real-time here: https://data.spark.fi/savings. sUSDC can be redeemed at any time for the underlying USDC plus earned yield. There are no additional fees, and users may withdraw up to the available amount in Sky reserves, which currently total $2.61 billion. While sUSDS is a yield-bearing representation of USDS. Users can deposit both USDS and USDC into the USDS Savings Vault and receive sUSDS, which similarly accrues the yields based on the SSR.

In parallel, Spark brings liquidity to the system through the Spark Liquidity Layer. Ensuring that users can always exit their positions in sUSDC and sUSDS with immediate settlement and no slippage.

On Unichain, Spark introduces a new use for the ~$150M of USDC liquidity already present on the network. sUSDC gives holders a native way to earn yield on their stablecoins while keeping their capital composable across lending markets, savings vaults, and DEXs. For both Optimism and Unichain, Spark brings stablecoin yield and collateral efficiency without requiring users to bridge or leave their chain.

Why sUSDC Matters

sUSDC represents a fundamental evolution of the centralized stablecoin model, specifically USDC. Unlike traditional stablecoins such as USDC, sUSDC natively accrues yield. This enables users to supply yield-generating collateral directly into lending protocols like Euler, unlocking improved capital efficiency from the outset.

Key advantages of sUSDC:

1. sUSDC functions as a dual-purpose asset. It generates yield while simultaneously serving as productive collateral within DeFi applications.

2. Its design simplifies user experience. There is no need to wrap, stake, or interact with external protocols to activate yield — the accrual is native and composable across the ecosystem.

3. It also aligns with growing liquidity on Unichain. As integrations deepen between sUSDC, USDT0, and other yield-capable stable assets, composability is preserved across lending markets, DEXs, and collateral frameworks.

The initial integration with Euler marks sUSDC’s entry into Unichain’s lending ecosystem. This sets the foundation for a more unified DeFi environment, where users can mint, save, borrow, and swap using yield-generating collateral — all without requiring complex or fragmented workflows.

Spark and the Optimism Collective are joining forces with a shared vision: to accelerate the growth of the Superchain — a network of chains that functions as a unified, composable ecosystem.

Optimism is contributing 2 million OP tokens to support aligned ecosystem growth. In parallel, Spark brings its core infrastructure and capital efficiency engine to the table - activating liquidity and delivering savings yield to USDC and USDS holders across the Superchain.

Spark is already live across OP Mainnet and Unichain with the following incentives rolling out:

• Spark Savings already live on both chains  — earn Spark Savings yield and OP rewards on sUSDC in app.spark.fi

• Superstack XP incentives (launching soon):

  • Providing liquidity & trading sUSDC/USDT0 on Velodrome (OP & Unichain)

  • Providing liquidity & trading sUSDC/USDT0 on Uniswap V4 (Unichain)

• Ecosystem Reward Programs (launching soon):

  • Velodrome’s rewards specifically for sUSDC/USDT0 pool on Unichain

  • Euler’s rewards for using sUSDC as collateral and borrowing USDT0

Timelines for these upcoming rewards will be announced on @sparkdotfi.

Spark is building the liquidity layer for a unified, chain-abstracted Ethereum — where capital moves freely, applications compose across chains, and users access yield without friction.

As part of our Superchain rollout, Spark is partnering with the Optimism Collective to implement native interoperability — the core infrastructure that enables single-block, cross-chain message passing across Superchain L2s.

The infrastructure will unlock:

• Assets like sUSDC, sUSDS and USDS can move cross-chain with native mint/burn mechanics

• Protocols can compose across chains, integrating Spark liquidity from any Superchain L2

• Apps can tap Spark’s savings, liquidity, or PSM modules, regardless of chain origin

Launching soon, native interoperability will allow users to deploy capital on one chain and earn yield on another, this will unlock new possibilities across the DeFi space, and Spark is ready to power the liquidity revolution on Day 1.

This is how we scale Ethereum: not one chain at a time, but all at once.

Spark is where it begins.

The job’s not done.