AT&T is believed to be evaluating whether to sell the headquarters in Manhattan, New York, that it has owned for more than 80 years.
The telecommunications giant confirmed that it had been speaking to estate agents about the property over the past few weeks, and the rumoured transaction could bring it in up to $150 million.
The company is expected to lease back between 30-40 per cent of the office space from any potential buyer.
Cotton seedling freezes to death as Chang'e-4 shuts down for the Moon's 14-day lunar night
Fortnite easily out-earns PUBG, Assassin's Creed Odyssey and Red Dead Redemption 2 in 2018
Meteor showers as a service will be visible for about 100 kilometres in all directions
Saturn's rings only formed in the past 100 million years, suggests analysis of Cassini space probe data
New findings contradict conventional belief that Saturn's rings were formed along with the planet about 4.5 billion years ago