USDC is a lending market on Kamino (Solana), listed as Nest Market USDC. Depositors supply USDC to the market and earn a variable interest rate paid by borrowers, who post collateral and are liquidated if their loan outgrows the market's limits. The rate floats with utilization — how much of the supplied USDC is borrowed at the time — so the market is used to earn on an idle USDC balance, or to borrow against collateral without selling it.