Bellevue, Washington-based T-Mobile US, Inc. (TMUS) provides mobile communications services. Valued at $190.1 billion by market cap, the company offers wireless voice, messaging, and data services.
Shares of this leading telco operator have underperformed the broader market over the past year. TMUS has declined 26.5% over this time frame, while the broader S&P 500 Index ($SPX) has rallied nearly 22.2%. In 2026, TMUS stock is down 12.7%, compared to the SPX’s 13% rise on a YTD basis.