Jon Brodkin, writing for Ars Technica:

Sen. Ron Wyden (D-Ore.) recently urged all four major carriers to stop the practice, and today he published responses he received from Verizon, AT&T, T-Mobile USA, and Sprint.

Wyden’s statement praised Verizon for “taking quick action to protect its customers’ privacy and security,” but he criticized the other carriers for not making the same promise.

“After my investigation and follow-up reports revealed that middlemen are selling Americans’ location to the highest bidder without their consent or making it available on insecure Web portals, Verizon did the responsible thing and promptly announced it was cutting these companies off,” Wyden said. “In contrast, AT&T, T-Mobile, and Sprint seem content to continuing to sell their customers’ private information to these shady middle men, Americans’ privacy be damned.”

AT&T changed its stance shortly after Wyden’s statement.