Gravy Analytics has been one of the most important companies in the location data industry for years, collating smartphone location data from around the world selling some to the U.S. government. Hackers say they stole a mountain of data.

Hackers have reportedly breached Gravy Analytics, a parent company of Venntel that sells smartphone location data to the U.S. government. The hackers claim to have stolen considerable data, including customer lists, industry information and individuals’ location data. They are threatening to make the data public.