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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, 2023

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. ☒

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements. ☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐

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, 2023, the aggregate market value of the voting and non-voting common equity held by non-affiliates was $73.2 billion based on the closing sale price as reported on the NASDAQ Global Select Market. As of January 31, 2024, there were 1,186,867,575 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 2024 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, 2023

Table of Contents

Cautionary Statement Regarding Forward-Looking Statements

This Annual Report on Form 10-K (“Form 10-K”) of T-Mobile US, Inc. (“T-Mobile,” “we,” “our,” “us” or the “Company”) 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:

• competition, industry consolidation and changes in the market for wireless communications services and other forms of connectivity;

• criminal cyberattacks, disruption, data loss or other security breaches;

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

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

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

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

• challenges in modernizing our existing applications and systems;

• the impacts of the actions we have taken and conditions we have agreed to in connection with the regulatory proceedings and approvals of our merger (the “Merger”) with Sprint Corporation (“Sprint”) pursuant to a 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”), including the acquisition by DISH Network Corporation (“DISH”) of the prepaid wireless business operated under the Boost Mobile and Sprint prepaid brands (excluding the Assurance brand Lifeline customers and the prepaid wireless customers of Shenandoah Personal Communications Company LLC (“Shentel”) and Swiftel Communications, Inc.), including customer accounts, inventory, contracts, intellectual property and certain other specified assets, and the assumption of certain related liabilities (collectively, the “Prepaid Transaction”), the complaint and proposed final judgment (the “Final Judgment”) agreed to by us, Deutsche Telekom AG (“DT”), Sprint, SoftBank Group Corp. (“SoftBank”) and DISH with the U.S. District Court for the District of Columbia, which was approved by the Court on April 1, 2020, as amended on October 23, 2023, 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 costs incurred in tracking and monitoring compliance over multiple years;

• adverse economic, political or market conditions in the U.S. and international markets, including changes resulting from increases in inflation or interest rates, supply chain disruptions and impacts of geopolitical instability, such as the Ukraine-Russia and Israel-Hamas wars and further escalations thereof;

• sociopolitical volatility and polarization;

• our inability to manage the ongoing arrangements entered into in connection with the Prepaid Transaction, and known or unknown liabilities arising in connection therewith;

• the timing and effects of any future acquisition, divestiture, 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;

• our substantial level of indebtedness and our inability to service our debt obligations in accordance with their terms;

• changes in the credit market conditions, credit rating downgrades or an inability to access debt markets;

• the risk of future material weaknesses we may identify 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 and increased costs from existing or future regulatory or legal proceedings;

• difficulties in protecting our intellectual property rights or if we infringe on the intellectual property rights of others;

• 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;

• our wireless licenses, including those controlled through leasing agreements, are subject to renewal and may be revoked;

• our exclusive forum provision as provided in our Fifth Amended and Restated Certificate of Incorporation (the “Certificate of Incorporation”);

• interests of DT, our controlling stockholder, which may differ from the interests of other stockholders;

• the dollar amount authorized for our 2023-2024 Stockholder Return Program (as defined in Note 13 – Stockholder Return Programs of the Notes to the Consolidated Financial Statements) may not be fully utilized, and our share repurchases and dividend payments pursuant thereto may fail to have the desired impact on stockholder value; and

• 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.

In addition, historical, current, and forward-looking environmental, social and governance (“ESG”) related statements may be based on standards for measuring progress that are still developing and internal controls and processes that continue to evolve. Our ESG initiatives are subject to additional risks and uncertainties, including regarding the evolving nature of data availability, quality, and assessment; related methodological concerns; our ability to implement various initiatives under expected timeframes, cost, and complexity; our dependency on third parties to provide certain information and to comply with applicable laws and policies; and other unforeseen events or conditions. For example, we note that standards and expectations regarding greenhouse gas (“GHG”) accounting and the processes for measuring and counting GHG emissions and GHG emission reductions are evolving, and it is possible that our approaches both to measuring our emissions and to reducing emissions and measuring those reductions may be, either currently by some stakeholders or at some point in the future, considered inconsistent with common or best practices with respect to measuring and accounting for such matters, and reducing overall emissions. These factors, as well as others, may cause results to differ materially and adversely from those expressed in any of our forward-looking statements. 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. Additionally, we may provide information that is not necessarily material for SEC reporting purposes but that is informed by various ESG standards and frameworks (including standards for the measurement of underlying data), internal controls, and assumptions or third-party information that are still evolving and subject to change. Our disclosures based on any standards may change due to revisions in framework requirements, availability of information, changes in our business or applicable governmental policies, or other factors, some of which may be beyond our control.

Investors and others should note that we announce material information to our investors using our investor relations website (https://investor.t-mobile.com), newsroom website (https://t-mobile.com/news), 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 X (formerly Twitter) account (https://twitter.com/TMobileIR), the @MikeSievert X account (https://twitter.com/MikeSievert), which Mr. Sievert also uses as a means for personal communications and observations, and the @TMobileCFO X Account (https://twitter.com/tmobilecfo) and our Chief Financial Officer’s LinkedIn account (https://www.linkedin.com/in/peter-osvaldik-3887394), both of which Mr. Osvaldik also uses as a means for personal communication 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.

PART I.