AT&T, T-Mobile and Sprint have sold access to subscribers' real-time location data to aggregators, which in turn have sold it to about 250 bounty hunters and related businesses, according to a report. In some cases, the data allowed users to track individuals to their specific locations inside a building. Some companies made thousands of location requests to data brokers; one made more than 18,000 such requests in just over a year. The news, which sparked widespread outrage, prompted a range of responses, including demands for federal action.