Big Brother isn’t always doing the watching—or the listening. Wiretapping at the government’s behest has become a growing business for some private companies, including Virginia-based Subsentio, a Latin word meaning “notice secretly.”

Founded in 2004, Subsentio LLC initially served small U.S.-based phone companies by helping them respond to requests for private customer information that government investigators made under the Communications Assistance for Law Enforcement Act. But Subsentio expanded its reach in 2015 with the acquisition of a division of its rival Neustar Inc. Now, Subsentio works with some of the world’s largest telecommunication service providers.