USDCx on Miden: Stablecoins with Privacy

Today we're announcing that USDCx on Miden is coming soon — a native, USDC-backed stablecoin, issued by Miden via Circle xReserve.

That means Miden’s native stablecoin will be private by default.

You will be able to hold and move USDCx onchain without publishing balances, counterparties, or transaction history to the world.

Here’s why we think this is one of the missing pieces of onchain finance.

Stablecoins are winning

Stablecoins are the most successful products that the digital asset industry has ever produced. The market sits at around $300 billion. Citi projects it will hit $1.9 trillion by 2030 — $4 trillion in their bull case. The GENIUS Act gave dollar-backed stablecoins a federal regulatory framework in the U.S.  A whole new onchain economy is forming, and stablecoins are becoming its currency of choice.

Circle built the foundation. USDC — issued by regulated affiliates of Circle, backed by highly liquid cash and cash-equivalent assets — is the most widely used regulated stablecoin in the market. And with xReserve, Circle now provides the infrastructure that lets blockchains like Miden deploy a native, USDC-backed stablecoin that is fully interoperable with USDC across supported chains.

The transparency problem

Here’s the bottleneck.

On most public blockchains, every transaction is public. Every balance, every counterparty, every payment — visible to anyone, forever. And blockchain analytics are only getting more sophisticated. The chains are becoming more transparent over time.

Think about what that means for anyone doing serious business. No company wants to publish  its payroll. No treasury team wants to show its positions. No supplier wants competitors reading its invoices off a block explorer.

For the institutions and individuals who represent the next wave of onchain activity, privacy isn't a feature. It's a necessity.

Enter USDCx on Miden

USDCx on Miden offers a more private alternative.

Transactions are private by default. Ownership and provenance are provable on demand. USDCx is backed one-to-one by USDC held in xReserve, a Circle-deployed smart contract, with minting enabled via xReserve attestations — so you get privacy on Miden without giving up the deepest liquidity and most established reserve model in the industry.

And privacy here doesn't mean total darkness. Miden's selective disclosure lets you prove your balances, provenance, or status to auditors, regulators, and counterparties. Institutions get the confidentiality of infrastructure, with the accessibility and speed of crypto.

Why institutions need Miden

Miden is a zero-knowledge blockchain that works differently from many other networks. You execute and prove your transactions locally, on your own device. The network verifies proofs — it never re-executes your transactions or sees your data.

That one design decision does two jobs at once. Your sensitive information stays with you. And because the network's only job is verifying compact proofs, the chain scales as usage grows rather than degrading under it.

In other words: Miden is a high-performance chain that puts users in control of their data. That's not something you can bolt onto a first-generation blockchain. It has to be the architecture — and on Miden, it is.

What comes next

USDCx on Miden arrives as we head to mainnet this summer, the product of seven years of development that began at Facebook (Meta) and continued at Polygon, from which Miden spun out in April 2025, backed by a16z crypto, 1kx, Hack VC, and others.

And a private stablecoin is the foundation, not the finish line. We're partnering with application developers building across the PriFi Stack — private wallets, payments, treasury management, payroll, and more, all made possible by the combination of Miden's privacy-first architecture and USDCx. We'll have much more to say about that very soon.

The second act

The first act of stablecoins was access: internet dollars available globally.

The second act is discretion: stablecoins that businesses, institutions, and ordinary people can actually use — because using them doesn't require broadcasting everything.

USDCx on Miden is that second act.