Being an economist does not mean you automatically know how Circle (a payments company based in the US) issues the ERC-20 token that is called "USDC", or how the redemptions for that work.
You can read about it here: https://www.circle.com/en/usdc and here https://www.centre.io/usdc
You can see centralized and decentralized exchanges with USDC liquidity here: https://www.coingecko.com/en/coins/usd-coin#markets