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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the fiscal year ended December 31, 2020

or

☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934

For the transition period from to

Commission File Number: 1-33409

T-MOBILE US, INC.

(Exact name of registrant as specified in its charter)

12920 SE 38th Street

Bellevue, Washington

(Address of principal executive offices)

98006-1350

(Zip Code)

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☒ No

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes No ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company,” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report. ☒

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). Yes ☐ No ☒

As of June 30, 2020, the aggregate market value of the voting and non-voting common equity held by non-affiliates was $40.7 billion based on the closing sale price as reported on the NASDAQ Global Select Market. As of February 17, 2021, there were 1,242,804,085 shares of common stock outstanding.

DOCUMENTS INCORPORATED BY REFERENCE

Part III of this Annual Report on Form 10-K will be incorporated by reference from certain portions of the definitive Proxy Statement for the Registrant’s 2021 Annual Meeting of Stockholders, which definitive Proxy Statement will be filed with the Securities and Exchange Commission pursuant to Regulation 14A or will be included in an amendment to this Report.

T-Mobile US, Inc.

Form 10-K

For the Year Ended December 31, 2020

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Cautionary Statement Regarding Forward-Looking Statements

This Annual Report on Form 10-K (“Form 10-K”) includes forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995. All statements, other than statements of historical fact, including information concerning our future results of operations, are forward-looking statements. These forward-looking statements are generally identified by the words “anticipate,” “believe,” “estimate,” “expect,” “intend,” “may,” “could” or similar expressions. Forward-looking statements are based on current expectations and assumptions, which are subject to risks and uncertainties that may cause actual results to differ materially from the forward-looking statements. The following important factors, along with the Risk Factors included in Part I, Item 1A of this Form 10-K, could affect future results and cause those results to differ materially from those expressed in the forward-looking statements:

• natural disasters, public health crises, including the COVID-19 pandemic (the “Pandemic”), terrorist attacks or similar incidents;

• adverse economic, political or market conditions in the U.S. and international markets, including those caused by the Pandemic;

• competition, industry consolidation and changes in the market condition for wireless services;

• data loss or other security breaches;

• the scarcity and cost of additional wireless spectrum, and regulations relating to spectrum use;

• our inability to retain or motivate key personnel, hire qualified personnel or maintain our corporate culture;

• our inability to take advantage of technological developments on a timely basis;

• system failures and business disruptions, allowing for unauthorized use of or interference with our network and other systems;

• the impacts of the actions we have taken and conditions we have agreed to in connection with the regulatory proceedings and approvals of the Transactions (as defined below), including the Prepaid Transaction (as defined in Note 1 - Summary of Significant Accounting Policies of the Notes to the Consolidated Financial Statements), the complaint and proposed final judgment (the “Consent Decree”) agreed to by us, Deutsche Telekom AG (“DT”), Sprint Corporation (“Sprint”), SoftBank Group Corp. (“SoftBank”) and DISH Network Corporation (“DISH”) with the U.S. District Court for the District of Columbia, which was approved by the Court on April 1, 2020, the proposed commitments filed with the Secretary of the Federal Communications Commission (“FCC”), which we announced on May 20, 2019, certain national security commitments and undertakings, and any other commitments or undertakings entered into including but not limited to those we have made to certain states and nongovernmental organizations (collectively, the “Government Commitments”), and the challenges in satisfying the Government Commitments in the required time frames and the significant cumulative cost incurred in tracking, monitoring and complying with them;

• our inability to manage the ongoing commercial and transition services arrangements that we entered into with DISH in connection with the Prepaid Transaction, which we completed on July 1, 2020 (collectively, the “Divestiture Transaction”), and known or unknown liabilities arising in connection therewith;

• the effects of any future acquisition, investment, or merger involving us;

• any disruption or failure of our third parties (including key suppliers) to provide products or services for the operation of our business;

• the occurrence of high fraud rates or volumes related to device financing, customer payment cards, third-party dealers, employees, subscriptions, identities or account takeover fraud;

• our substantial level of indebtedness and our inability to service our debt obligations in accordance with their terms or to comply with the restrictive covenants contained therein;

• adverse changes in the ratings of our debt securities or adverse conditions in the credit markets;

• the risk of future material weaknesses we may identify while we work to integrate and align policies, principles and practices of the two companies following the Merger (as defined below), or any other failure by us to maintain effective internal controls, and the resulting significant costs and reputational damage;

• any changes in regulations or in the regulatory framework under which we operate;

• laws and regulations relating to the handling of privacy and data protection;

• unfavorable outcomes of existing or future legal proceedings;

• our offering of regulated financial services products and exposure to a wide variety of state and federal regulations;

• new or amended tax laws or regulations or administrative interpretations and judicial decisions affecting the scope or application of tax laws or regulations;

• the possibility that we may be unable to renew our spectrum leases on attractive terms or the possible revocation of our existing licenses in the event that we violate applicable laws;

• interests of our significant stockholders that may differ from the interests of other stockholders;

• future sales of our common stock by DT and SoftBank and our inability to attract additional equity financing outside the United States due to foreign ownership limitations by the FCC;

• the volatility of our stock price and our lack of plan to pay cash dividends in the foreseeable future;

• failure to realize the expected benefits and synergies of the merger (the “Merger”) with Sprint, pursuant to the Business Combination Agreement with Sprint and the other parties named therein (as amended, the “Business Combination Agreement”) and the other transactions contemplated by the Business Combination Agreement (collectively, the “Transactions”) in the expected timeframes or in the amounts anticipated;

• any delay and costs of, or difficulties in, integrating our business and Sprint’s business and operations, and unexpected additional operating costs, customer loss and business disruption, including maintaining relationships with employees, customers, suppliers or vendors;

• unanticipated difficulties, disruption, or significant delays in our long-term strategy to migrate Sprint’s legacy customers onto T-Mobile’s existing billing platforms; and

• changes to existing or the issuance of new accounting standards by the Financial Accounting Standards Board or other regulatory agencies.

Given these risks and uncertainties, readers are cautioned not to place undue reliance on such forward-looking statements. We undertake no obligation to revise or publicly release the results of any revision to these forward-looking statements, except as required by law. In this Form 10-K, unless the context indicates otherwise, references to “T-Mobile,” “our Company,” “the Company,” “we,” “our,” and “us” refer to T-Mobile US, Inc. as a standalone company prior to April 1, 2020, the date we completed the Merger with Sprint, and on and after April 1, 2020, refer to the combined company as a result of the Merger.

Investors and others should note that we announce material financial and operational information to our investors using our investor relations website, press releases, SEC filings and public conference calls and webcasts. We intend to also use certain social media accounts as means of disclosing information about us and our services and for complying with our disclosure obligations under Regulation FD (the @TMobileIR Twitter account (https://twitter.com/TMobileIR) and the @MikeSievert Twitter account (https://twitter.com/MikeSievert), which Mr. Sievert also uses as a means for personal communications and observations). 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 our press releases, SEC filings and public conference calls and webcasts. The social media channels that we intend to use as a means of disclosing the information described above may be updated from time to time as listed on our Investor Relations website.

Table of Contents

PART I.