AT&T Inc. is the second largest provider of mobile telephone services and the largest provider of fixed telephone services in the United States, and also provides broadband subscription television services through DirecTV. It is the largest telecommunications company in the world by revenue [Wikipedia] and was ranked at #4 of the Most Valuable Global Brands 2016.
The typographic cornerstone of the brand is Omnes by Darden Studio. In his review of AT&T’s latest brand update in 2016, design critic Armin Vit comments:
Omnes […] is one of my favorite typefaces and it works nicely as a playful corporate typeface in its lighter weights.
AT&T uses a custom version spanning several weights mostly from the lighter end of the family’s range, plus italics. The friendly sans serif with selective rounding is employed across all media, from the various websites to corporate brochures, reports, infographics, videos, and more.