T-Mobile US reported lower profit despite higher revenue in its fourth quarter as it added fewer subscribers for its most lucrative phone offering than analysts expected. The company's postpaid subscriber growth lagged behind projections, a development that could intensify pressure on its wireless rivals.

While overall revenue increased, the shortfall in high-margin postpaid additions suggests challenges in retaining customers or competing effectively in a market where growth has historically been driven by such accounts. Investors reacted negatively to the news, sending shares down as the results highlighted potential headwinds for the nation's third-largest carrier. The outcome underscores the competitive intensity in the wireless sector, where maintaining subscriber momentum remains critical for financial performance.