T-Mobile US Inc

Evaluation of Disclosure Controls and Procedures

We maintain disclosure controls and procedures designed to ensure information required to be disclosed in our periodic reports filed or submitted under the Exchange Act is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms. Our disclosure controls include the use of a Disclosure Committee which is comprised of representatives from our Accounting, Legal, Treasury, Technology, Risk Management, Government Affairs and Investor Relations functions and are designed to ensure that information required to be disclosed in the reports we file or submit under the Exchange Act is accumulated and communicated to our management, including our principal executive officer and principal financial officer, as appropriate, to allow timely decisions regarding required disclosure.

Under the supervision and with the participation of our management, including our Chief Executive Officer and our Chief Financial Officer, we carried out an evaluation of the effectiveness of the design and operation of our disclosure controls and procedures, as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act. Based upon that evaluation, our Chief Executive Officer and Chief Financial Officer concluded that our disclosure controls and procedures were effective, as of the end of the period covered by this Form 10-Q.

The certifications required by Section 302 of the Sarbanes-Oxley Act of 2002 (the “Sarbanes-Oxley Act”) are filed as Exhibits 31.1 and 31.2 to this Form 10-Q.

Changes in Internal Control over Financial Reporting

There were no changes in our internal control over financial reporting, as defined in Rules 13a-15(f) and 15d-15(f) of the Exchange Act, during our most recently completed fiscal quarter that materially affected, or are reasonably likely to materially affect, our internal control over financial reporting.