Companies need to have an Independent Sales Organization designation if they wish to sell credit card processing services through Visa. Companies that are designated an ISO company are often listed by Visa on their ISO list so that consumers can verify that the company is actually a registered affiliate of the organization. Some sales organizations may also sell branded merchant accounts under Visa ISOs without maintaining their own.
ISOs work with Visa but are still able to set many of their own terms, including marked up processing rates and the fees they charge their customers. ISOs also develop their own merchant account contracts and retain their own customers independently from Visa. Many ISOs operate as a connecting layer in point-of-sale applications such as mobile accessories, payment gateways and terminals.
Other types of credit card, such as MasterCard, American Express and Discover, have other designations for their partners. MasterCard has the MSP program which operates extremely similarly to the Visa ISO program.