The terms “closed loop”, “open loop”, “restricted open loop” or “semi-closed loop” are not used uniformly in practice. They are used colloquially to further describe card systems with regard to card acceptance. The term “closed-loop cards” refers to cards that can only be redeemed at the retailer who issued them. Due to their legal ambiguity, these terms should not be used to make statements regarding the permissibility of card systems from a supervisory law perspective.