All four major U.S. carriers are about to be hit with big fines.

The FCC is planning to fine AT&T, Sprint, T-Mobile, and Verizon at least $200 million in total for selling customer's location data. The carriers will have a chance to challenge the fines before they become final, Reuters reports, but the final amount could end up being higher.

It's said that the FCC will officially announce these fines as soon as tomorrow.

The four major U.S. carriers have had some major issues with customer location data in the past couple of years. In May 2018, a flaw with the website for a company called LocationSmart allowed anyone to get the location of another person's cellphone, with one person saying they were able to get the coordinates of a phone that was within 100 yards of their actual location.

Fast-forward to January 2019 and AT&T, Sprint, and T-Mobile were found to have been selling customer location data to aggregators who then made it available to other parties. In one example, a bounty hunter sold a T-Mobile customer's location info for $300, complete with a Google Maps screenshot and approximate longitude and latitude.

The major U.S. carriers have since ended their work with these location aggregators, but that hasn't stopped the FCC from finding that they violated the law and will be hit with fines.