What is USD Coin (USDC)? USDC is a stablecoin built on Ethereum. USDC maintains a stable value of $1 USD because each USDC is collateralized by a US dollar. USDC are issued by regulated and licensed financial institutions that maintain full reserves of the equivalent fiat currency, in that case 1 USDC:1 USD ratio. Because USDC is a digital representation of USD on the Ethereum blockchain, it allows USDC to travel quickly anywhere in the world just like Ether.