This research looked into how Independent Service Operators (ISOs) impact ATM markets. The study compared two scenarios where ISOs make money: by collecting interchange fees or charging customers directly. They discovered that when an ISO enters the market, the overall number of ATMs increases, regardless of how the ISO is funded. If ISOs get interchange fees, account charges rise, but they drop when ISOs charge customers directly. The study found that consumers might not benefit from ISO entry, as consumer benefits can go up or down depending on how the ISO is financed. If a regulator can manage interchange fees, an ISO funded by interchange fees can boost consumer benefits, while a surcharging ISO may lessen them.