As you can imagine, Circle maintains fairly sophisticated minting operations able to execute around the clock. All that is necessary for coins to be minted is for Circle to broadcast a properly signed transaction.
Now, of course, Circle can't just mint a limitless supply because we have a minting allowance set by CENTRE. While CENTRE itself can't mint coins, they do operate a minting allowance system with around the clock availability which can grant Circle a additional allowance per a ruleset to effectively manage risk.
This might seem to be getting into the weeds a bit but support for multiple minters (Circle and Coinbase here for example) is a significant differentiator between USDC and other reserve backed stablecoins.
As you can imagine, Circle maintains fairly sophisticated minting operations able to execute around the clock. All that is necessary for coins to be minted is for Circle to broadcast a properly signed transaction.
Now, of course, Circle can't just mint a limitless supply because we have a minting allowance set by CENTRE. While CENTRE itself can't mint coins, they do operate a minting allowance system with around the clock availability which can grant Circle a additional allowance per a ruleset to effectively manage risk.
This might seem to be getting into the weeds a bit but support for multiple minters (Circle and Coinbase here for example) is a significant differentiator between USDC and other reserve backed stablecoins.