T-Mobile's CEO, Mike Sievert, indicated that the company's device upgrade rate is currently low, which has raised concerns among investors. Following this statement, T-Mobile's stock experienced a significant decline of over 6% on December 10. Additionally, Sievert clarified that his earlier comments regarding the fourth quarter were 'misinterpreted.' Meanwhile, AT&T's CEO, John Stankey, is set to address shareholders at the UBS Global Media & Communications Conference on December 10, where he will outline a multi-year strategic growth plan focused on customer-centric network investments, 5G expansion, fiber deployment, and a financial capacity of $50 billion. T-Mobile also reiterated its positive growth momentum during the conference, despite the recent stock drop.