Arc

Circle’s Layer 1. Carries the pool: receivables, tranche tokens, the loss waterfall and the first-loss floor.

Solana

Carries distribution. Junior and mezzanine risk capital is raised here.

CCTP and Gateway

Investors hold one USDC balance and fund a pool on either chain without bridging manually.

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Why split it at all

The two sides of the capital stack live in different places. Institutions buy senior notes and need fiat rails, regulated custody and a chain their own compliance teams already accept. Risk-seeking capital that will hold a junior tranche is abundant on Solana and scarce among institutions. Asking either side to move to the other’s chain loses one of them. So the pool sits where the fiat and the institutions are, distribution sits where the risk capital is, and USDC moves between them.

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Which comes first

Arc first, because the pool needs fiat at both ends and PRISM’s senior buyers are the institutions already validating that chain. Solana second — it is M5 on the roadmap, the last milestone.
Today the tranche mechanics run on Solana devnet only. Nothing is deployed to Arc mainnet yet — that is M1. See Where things stand.