In the United States, CPNI (Customer Proprietary Network Information) is information that telecommunications services such as local, long distance, and wireless telephone companies acquire about their subscribers. It includes not only what services they use but their amount and type of usage. The Telecommunications Act of 1996 together with clarifications from the Federal Communications Commission (FCC) generally prohibits the use of that information without customer permission, even for the purpose of marketing the customers other services . In the case of customers who switch to other service providers, the original service provider is prohibited from using the information to try to get the customer back. CPNI includes such information as optional services subscribed to, current charges, directory assistance charges, usage data, and calling patterns.
The CPNI rules do not prohibit the gathering and publishing of aggregate customer information nor the use of customer information for the purpose of creating directories.