T-Mobile US's stock surged 5.04% during intraday trading on Wednesday, marking a significant reversal from earlier losses. The wireless carrier reported its fourth-quarter 2025 financial results earlier in the session, which initially pressured the shares.

The company's quarterly earnings of $1.88 per share fell short of analyst expectations of $2.06, impacted by severance costs related to workforce transformation. Furthermore, T-Mobile added 962,000 postpaid phone subscribers, slightly below the estimated 981,330, as intensified promotional competition from rivals weighed on customer growth.

However, investor sentiment turned sharply positive following the company's capital markets day, where it significantly raised its multi-year financial outlook. T-Mobile now expects 2027 service revenue of $80.5 billion to $81.5 billion, up from prior guidance of $75 billion to $76 billion, and projects a core adjusted EBITDA contribution of $3 billion from artificial intelligence by the end of 2027. The company also announced a new AI platform featuring live translation capabilities and plans to approximately double its first-quarter share repurchases to up to $5 billion.