Circle Freezes $12.6M in Zama cUSDC With No Warning Given

A fresh controversy has erupted in the crypto industry after Circle blocklisted Zama’s confidential USDC (cUSDC) contract on Ethereum. It is freezing approximately $12.6 million in user funds. Blockchain investigator ZachXBT first reported the freeze on May 30. He raised questions about the balance between compliance requirements and decentralization.

The incident immediately sparked debate across the crypto community. Zama is known for using fully homomorphic encryption (FHE), a privacy technology that allows transaction details to remain encrypted while still being verifiable on-chain. However, the event highlights a major challenge facing privacy-focused protocols built on centralized stablecoins such as USDC.

Circle Blocklists Zama cUSDC Contract

According to ZachXBT, Circle added the Zama cUSDC contract address to its blocklist without prior notice to the Zama team. The affected contract currently holds around $12.6 million worth of USDC. The frozen contract address is publicly listed in Zama’s documentation and blockchain explorers. Despite the freeze, no significant outflows have been recorded from the contract since the action was taken.

ZachXBT noted that the reason behind the freeze remains unclear. However, the move effectively halted access to millions of dollars in user funds while the situation is investigated. The event quickly became one of the most discussed stories involving Circle this year. Especially given previous concerns over the company’s ability to freeze assets at the smart contract level.

Zama Says Freeze Was Collateral Damage

Shortly after reports emerged, Zama provided additional context regarding the incident. According to the team, Circle’s compliance system flagged an external wallet that had deposited funds into the cUSDC contract. Because those assets were held within the broader contract. The entire system was swept into a standard holding freeze.

Co-founder Rand Hindi confirmed that the team is actively investigating the issue. Zama’s legal team is also working to isolate the flagged wallet and restore access for unaffected users as quickly as possible.

Overnight Finance Connection Raises Questions

Further analysis by ZachXBT revealed that the frozen address may have links to funds associated with Overnight Finance. The wallet reportedly participated in a recent governance vote involving treasury allocation discussions. Overnight Finance has previously faced allegations from some community members regarding treasury management and alleged rug pull concerns. Although no direct connection has been officially confirmed.

Adding another layer of complexity, ZachXBT highlighted that Patagon Management, a plaintiff involved in civil litigation against Overnight Finance. This may have linked the address to Zama during court proceedings. At this stage, the exact relationship between the frozen funds, Overnight Finance, and the blocklist remains unclear.

What This Means for Privacy Protocols

The incident creates an important test case for privacy-focused blockchain infrastructure. For developers, the freeze demonstrates how centralized stablecoins can create unexpected risks for decentralized applications. Even when a protocol itself is not under investigation, a single flagged participant may impact an entire contract.

For users, the event serves as a reminder that assets backed by centralized issuers remain subject to compliance controls regardless of the underlying technology. The case also raises broader questions about how privacy protocols can design systems that better isolate individual wallets and reduce contract-wide exposure.

What Happens Next?

The immediate focus is on whether Circle and Zama can resolve the freeze without causing permanent disruption to users. Meanwhile, the crypto community continues to debate whether compliance actions of this scale should come with greater transparency. As the investigation develops, the Circle blocklist event could become a defining example of the ongoing tension between privacy, decentralization and regulatory compliance. The outcome may influence how future privacy protocols integrate stablecoins and manage compliance risks across the broader DeFi ecosystem.