The Un-carrier continues to deliver growth adding 23,000 new customers per day on average for the past two years

Preliminary Full-Year 2015 Customer Highlights:

• 8.3 million total net customer additions
• 4.5 million branded postpaid net customer additions
• 3.5 million branded postpaid phone net customer additions
• 1.3 million branded prepaid net customer additions

• 304 million people now covered by the nation’s fastest 4G LTE network ** Preliminary Fourth Quarter 2015 Customer Highlights ** :

• 2.1 million total net customer additions

• 1.3 million branded postpaid net customer additions
• 917,000 branded postpaid phone net customer additions
• 469,000 branded prepaid net customer additions
• Branded postpaid phone churn of 1.46%, down 27 basis points year-over-year

BELLEVUE, Wash. — January 6, 2016 - T-Mobile US, Inc. (NASDAQ: TMUS) today provided a preliminary view of key customer results for the fourth quarter of 2015, once again demonstrating that customers are choosing T-Mobile for flexibility, choice and value.

“In 2015 we AGAIN saw 8.3 million customers come to T-Mobile, and 2.1 million in Q4 - marking 11 consecutive quarters of over 1 million net adds and 3 quarters in a row with more than 2 million total nets for the Un-carrier,” said John Legere, President and CEO of T-Mobile. “That means we added 23,000 customers per day, EVERY DAY for the last two years, so trust me when I say we have NO plans to stop disrupting the status quo in wireless!”

Preliminary Fourth Quarter and Full-Year 2015 Customer Results

In the fourth quarter of 2015, T-Mobile added 2.1 million net customers, bringing its total customer count to more than 63 million at year-end 2015. This was the eleventh consecutive quarter that the Company has generated more than 1 million net customer additions and the third consecutive quarter with more than 2 million net customer additions. Full-year 2015 also marked the second consecutive year that the Company added more than 8 million net customers, which is expected to once again lead the wireless industry.

T-Mobile also saw ongoing strength in branded postpaid customers, reporting branded postpaid net customer additions of 1.3 million in the fourth quarter of 2015. This was the sixth consecutive quarter in which the Company has reported more than 1 million branded postpaid net customer additions. Branded postpaid phone net customer additions were 917,000 in the fourth quarter of 2015, bringing the total branded postpaid phone net customer additions to approximately 10 million since the launch of the Un-carrier. For full-year 2015, the Company added 4.5 million branded postpaid net customer additions, well above the revised guidance for branded postpaid net customer additions of 3.8 to 4.2 million provided in connection with the third quarter of 2015 earnings.

Branded prepaid net customer additions in the fourth quarter of 2015 were 469,000. For full-year 2015, the Company added 1.3 million branded prepaid net customer additions.

Wholesale net customer additions were 301,000 in the fourth quarter of 2015 and 2.4 million for full-year 2015.

Branded postpaid phone churn was 1.46% in the fourth quarter of 2015, down 27 basis points year-over-year, marking the best churn improvement of the year. Sequentially, churn was stable instead of the typical seasonal increase.

T-Mobile delivered on some major network milestones in 2015. The Company more than doubled its LTE footprint during the year, expanding its reach to 304 million Americans. T-Mobile also aggressively rolled out Extended Range LTE on low-band 700MHz A-Block spectrum, which is now live in over 300 markets covering 185 million Americans, while continuing to deploy Wideband LTE, which is now live nationwide.

America’s Un-carrier plans to share more details and its full financial results for fourth quarter and full-year 2015 in February.

Preliminary Customer Results

T-Mobile Social Media

Investors and others should note that the Company announces material financial and operational information to its investors using its investor relations website, press releases, SEC filings and public conference calls and webcasts. The Company also intends to use the @TMobileIR Twitter account (https://twitter.com/TMobileIR) and the @JohnLegere Twitter (https://twitter.com/JohnLegere) and Periscope accounts, which Mr. Legere also uses as a means for personal communications and observations, as means of disclosing information about the Company and its services and for complying with its disclosure obligations under Regulation FD. The information we post through these social media channels may be deemed material. Accordingly, investors should monitor these social media channels in addition to following the Company’s press releases, SEC filings and public conference calls and webcasts. The social media channels that the Company intends to use as a means of disclosing the information described above may be updated from time to time as listed on the Company’s investor relations website.