Circle has blacklisted the confidential USDC (cUSDC) contract address of privacy protocol Zama on the Ethereum network, resulting in the freezing of approximately $12.6 million. The action, disclosed by blockchain investigator ZachXBT, occurred about seven hours ago, with the reason for the freeze remaining unclear. Previously, in March 2026, ZachXBT reported that Circle had frozen over 16 hot wallets linked to various enterprises and protocols without providing transparency.