Osero, a stablecoin yield infrastructure project incubated by Stablewatch and Soter Labs, raised $13.5 million in a round led by the Sky Ecosystem and co-led by Plasma.

The round included angel investors representing USDT0, Maple, Accountable, Four Pillars, RedStone, The Rollup and Kairos Research, according to an announcement.

Stablecoins have grown to more than $300 billion, according to DeFiLlama data. Most yield from the assets backing those stablecoins still goes to issuers like Circle and Tether, leaving holders with no direct return and fintech firms with limited ways to offer stablecoin savings products without managing assets themselves.

Osero is launching three products. Osero Earn which lets wallets, neobanks, custodians and exchanges embed the Sky Savings Rate into their own interfaces. Osero App, which gives users direct access to the rate across chains, and Osero Foundry, which gives asset managers and structured product issuers a way to bring yield products onchain.

Osero Earn is meant to be integrated with roughly 10 lines of code, according to the company. The product routes deposits into the Sky Savings Rate while Osero handles the underlying asset-management, routing and risk infrastructure.

Osero Foundry will provide up to $2.5 billion in allocation capacity for anchor funding, swap liquidity and lending liquidity. Each deployment will go through a Basel III-inspired risk review, Osero said.

The $13.5 million raise will fund capital requirements for Osero’s first Foundry allocations. The capital will be used to underwrite the first cohort of deployments under the risk framework used for the Sky Protocol’s assessment process.

Sky, formerly MakerDAO, has been expanding the balance sheet and distribution network around USDS and sUSDS. Sky received a B- rating from S&P last year, in the first credit rating assigned by the agency to a DeFi protocol.

Sky-backed projects have also pushed into yield-bearing real-world asset products. Obex said in March it was spreading $1 billion across credit, energy and AI assets to expand stablecoin yield.

Plasma, which co-led the round, is building a stablecoin-focused blockchain. Its token sale drew $373 million last year in an oversubscribed sale.