Usury
Also called: usury laws, loan sharking, usury cap
Usury is charging interest above the legal maximum, and usury laws are the caps that define it. The caps vary wildly by jurisdiction and product, which is why US card issuers domicile in states with no cap at all. The policy tension is genuine: caps stop the most extreme lending, but binding caps also push marginal borrowers out of legal credit entirely, toward unregulated lenders whose enforcement mechanisms are worse than a high APR.