Circle holds one dollar for every dollar minted, we do not run a fractional reserve. The CENTRE Consortium holds minters (of which Circle is one) to strict auditing requirements. While this information is regularly published, you can see all minting and burning operations (as well as all transfers and other token operations) in realtime on the Ethereum blockchain. See etherscan: https://etherscan.io/address/0xa0b86991c6218b36c1d19d4a2e9eb... There are always as many USDCs in circulation as there are fiat dollars backing them up in traditional bank accounts. The only way minters produce more in a 1 to 1 manner is if someone wires traditional dollars in. Likewise, Circle will burn USDCs in a 1 to 1 manner as requests for traditional fiat dollar withdrawals are processed.