The company added thousands of wireless subscribers over the last few years, thanks to hefty discounts on smartphones, industry-low plan prices and an edge in 5G. But a slowdown in wireless growth and bigger promotions by rivals amid rising costs are hurting T-Mobile now.

The company said total revenue fell 2.5% to $20.27 billion in the quarter ended December, below Wall Street's estimate of $20.6 billion, according to Refinitiv data. It added 927,000 monthly bill-paying phone subscribers in the quarter.

T-Mobile's net income rose to $1.48 billion, or $1.18 per share, from $422 million, or 34 cents per share, a year earlier.

In January, the company said it was investigating a data breach that may have exposed 37 million postpaid and prepaid accounts, and it may incur significant costs related to the incident.

T-Mobile expects to add between 5 million and 5.5 million net monthly-bill paying subscribers in 2023, compared with the 6.4 million additions it reported in 2022.

(Reporting by Eva Mathews in Bengaluru; Editing by Shinjini Ganguli)