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.

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 and 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:

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,” “T-Mobile US,” “our Company,” “the Company,” “we,” “our,” and “us” refer to T-Mobile US, Inc., a Delaware corporation, and its wholly-owned subsidiaries.

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 thecertain 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 through April 30, 2020, the @JohnLegere Twitter (https://twitter.com/JohnLegere), Facebook and Periscope accounts, which Mr. Legere also uses as means for personal communications and observations, and on and after May 1, 2020 the @SievertMike Twitter (https://twitter.com/SievertMike) account, which Mr. Sievert also uses as a means of disclosing information about the Companyfor personal communications and its services and for complying with its disclosure obligations under Regulation FD.observations). The information we post through these social media channels may be deemed material. Accordingly, investors

T-Mobile USA, Inc. (“T-Mobile USA”), a Delaware corporation, was formed in 1994 as VoiceStream Wireless PCS (“VoiceStream”), a subsidiary of Western Wireless Corporation (“Western Wireless”). VoiceStream was spun off from Western Wireless in 1999, acquired by Deutsche Telekom AG (“Deutsche Telekom”DT”) in 2001 and renamed T-Mobile USA, Inc. in 2002.

In 2013, T-Mobile US, Inc., a Delaware corporation, was formed through the business combination betweenof T-Mobile USA and MetroPCS Communications, Inc. (“MetroPCS”). The business combination was accounted for as a reverse acquisition with T-Mobile USA as the accounting acquirer. Accordingly, T-Mobile USA’s historical financial statements became the historical financial statements of the combined company.

We provide wireless services to 72.686.0 million customers in the postpaid, prepaid and wholesale marketscustomers and generate revenue by providing affordable wireless communicationcommunications services to these customers, as well as a wide selection of wireless devices and accessories. Our most significant expenses are relatedrelate to acquiring and retaining high-quality customers, providing a full range of devices, compensating employees, and operating and expanding our network. We provide service, devices and accessories across our flagship brands, T-Mobile and MetroPCS,Metro by T-Mobile, through our owned and operated retail stores, third party distributors andas well as through our

We provide wireless communicationcommunications services to three primary categories of customers:

We generate the majority of our service revenues by providing wireless communicationcommunications services to branded postpaid and branded prepaid customers. Our ability to acquire and retain branded postpaid and prepaid customers is important to our business in the generation of service revenues, equipment revenues and other revenues. In 2017,2019, our service revenues generated by providing wireless communicationcommunications services by customer category were:

We provide wireless communicationcommunications services through a variety of service plan options. We also offer a wide selection of wireless devices, including smartphones, wearables, tablets and other mobile communication devices, which are manufactured by various suppliers. Services, devices and accessories are offered directly to consumers through the retail stores we operate, as well as through our websites and customer care channels. In addition, we sell devices to dealers and other third-party distributors for resale through independent third-party retail outlets and a variety of third-party websites.

Our primary service plan offerings,offering, which allowallows customers to subscribe for wireless communications services separately from the purchase of a device, include:

We provide mobile communicationwireless communications services utilizing mid-band spectrum licenses, such as Advanced Wireless Services (“AWS”) and Personal Communications Service (“PCS”), and low-band spectrum licenses utilizing our 600 MHz and 700 MHz spectrum, and mmWave spectrum.

The wireless telecommunicationscommunications services industry is highly competitive. We are the third largest provider of postpaid service plans and the second largest provider of prepaid service plans in the U.S. as measured by customers. Our competitors include other national carriers, such as AT&T Inc. (“AT&T”), Verizon Communications, Inc. (“Verizon”) and Sprint Corporation (“Sprint”).Sprint. AT&T and Verizon are significantly larger than uswe are and enjoy greater resources and scale advantages as compared to us. In addition, our competitors include numerous smaller regional carriers, existing MVNOs,mobile virtual network operators (“MVNOs”), including TracFone Wireless, Inc. and, Comcast Corporation, (“Comcast”), and future MVNOs, such as Charter Communications, Inc., and Altice USA, Inc., many of which offer or plan to offer no-contract, postpaid and prepaid service plans. Competitors also include providers who offer similar communication services, such as voice, messaging and data services, using alternative technologies or services. Competitive factors within the wireless telecommunicationscommunications services industry include pricing, market saturation, service and product offerings, customer experience, network investment and quality, development and deployment of technologies, availability of additional spectrum licenses and regulatory changes. Some competitors have shown a willingness to use aggressive pricing as a source of differentiation. Other competitors have sought to add ancillary services, like mobile video or music streaming services, to enhance their offerings. Taken together, the competitive factors we face continue to put pressure on growth and margins as companies compete to retain the current customer base and continue to add new customers.

As of December 31, 2017,2019, we employed approximately 51,00053,000 full-time and part-time employees, including network, retail, administrative and customer support functions.

The FCC regulates many key aspects of our business, including licensing, construction, the operation and use of our network, modifications of our network, control and ownership of our licenses and authorizations, the sale, transfer and acquisition of certain licenses, domestic roaming arrangements and interconnection agreements, pursuant to its authority under the Communications Act of 1934, as amended (“Communications Act”). The FCC has a number of complex requirements and proceedings that affect our operations and pending proceedings regarding additional or modified requirements that could increase our costs or diminish our revenues. For example, the FCC has rules regarding provision of 911 and E-911 services, porting telephone numbers, interconnection, roaming, internet openness or net neutrality, disabilities access, privacy and cybersecurity, consumer protection, and the universal service and Lifeline programs. Many of these and other issues are being considered in ongoing proceedings, and we cannot predict whether or how such actions will affect our business, financial condition or results of operations. Our ability to provide services and generate revenues could be harmed by adverse regulatory action or changes to existing laws and regulations. In addition, regulation of companies that offer competing services can impact our business indirectly.

WirelessExcept for operations in certain unlicensed frequency bands, wireless communications services providers generally must be licensed by the FCC to provide communications services at specified spectrum frequencies within specified geographic areas and must comply with the rules and policies governing the use of the spectrum as adopted by the FCC. The FCC issues each license for a fixed period of time, typically 1010-15 years independing on the case of cellular, PCS and point-to-point microwaveparticular licenses. AWS licenses have an initial term of 15 years, with successive 10-year terms thereafter. While the FCC has generally renewed licenses given to operating companies like us, the FCC has authority to both revoke a license for cause and to deny a license renewal if a renewal is not in the public interest. Furthermore, we could be subject to fines, forfeitures and other penalties for failure to comply with FCC regulations, even if any such non-compliance was unintentional. In extreme cases, penalties can include revocation of our licenses. The loss of any licenses, or any related fines or forfeitures, could adversely affect our business, results of operations and financial condition.

Additionally, Congress’ and the FCC’s allocation of additional spectrum for broadband commercial mobile radio service (“CMRS”), which includes cellular, PCS, miscellaneous wireless services and specialized mobile radio, could significantly increase and intensify competition. We cannot assess the impact that any developments that may occur in the U.S. economy or any future spectrum allocations by the FCC may have on license values. FCC spectrum auctions and other market

developments may adversely affect the market value of our licenses in the future. A significant decline in the value of our licenses could adversely affect our financial condition and results of operations. In addition, the FCC periodically reviews its policies on how to evaluate carriers’ spectrum holdings. A change in these policies could affect spectrum resources and competition among us and other carriers.

Congress and the FCC have imposed limitations on foreign ownership of CMRS licensees that exceed 20% direct ownership or 25% indirect ownership.ownership through an entity controlling the licensee. The FCC has ruled that higher levels of indirect foreign ownership, even up to 100%, are presumptively consistent with the public interest, albeit subject to review.but must be reviewed and approved. Consistent with that established policy, the FCC has issued a declaratory ruling authorizing up to 100% ownership of our companyCompany by Deutsche Telekom.DT. This declaratory ruling, and our licenses, are conditioned on Deutsche Telekom’sDT’s and the Company’s compliance with a network security agreement

In addition, the Federal Trade Commission (“FTC”) and other federal agencies have asserted that they have jurisdiction over some consumer protection and elimination and prevention of anticompetitive business practices with respect to the provision of non-common carrier services. Further, the FCC and the Federal Aviation Administration regulate the siting, lighting and construction of transmitter towers and antennae. Tower siting and construction are also subject to state and local zoning, as well as federal statutes regarding environmental and historic preservation. The future costs to comply with all relevant regulations are to some extent unknown and changes to regulations, or the applicability of regulations, could result in higher operating and capital expenses, or reduced revenues in the future.

The SEC maintains an internet site that contains reports, proxy and information statements, and other information regarding issuers that file electronically at www.sec.gov. Our Form 10-K and all other reports and amendments filed with or furnished to the SEC are also publicly available free of charge on the Investor Relationsinvestor relations section of our website at investor.t-mobile.com or at www.sec.gov as soon as reasonably practicable after these materials are filed with or furnished to the SEC. Our corporate governance guidelines, code of ethics for senior financial officers, code of business conduct, speak-up policy, supplier code of conduct, and charters for the audit, compensation, nominating and corporate governance and executive committees of our Board of Directors are also posted on the Investor Relationsinvestor relations section of our website at investor.t-mobile.com. The information on our websites is not part of this or any other report we file with, or furnishesfurnish to, the SEC.

In addition to the other information contained in this Form 10-K, the following risk factors should be considered carefully in evaluating T-Mobile. Our business, financial condition, liquidity, or operating results, as well as the price of our common stock and other securities, could be materially adversely affected by any of these risks.

We have multiple wireless competitors, some of which have greater resources than uswe have and compete for customers based principally on service/device offerings; price;offerings, price, network coverage, speed and quality;quality and customer service. We expect market saturation to continue to cause the wireless industry’s customer growth rate to be moderate in comparison with historical growth rates, or possibly negative, leading to ongoing competition for customers. We also expect that our customers’ appetite for data services will place increasing demands on our network capacity. This competition and our capacity will continue to put pressure on pricing and margins as companies compete for potential customers. Our ability to compete will depend on, among other things, continued absolute and relative improvement in network quality and customer service, effective marketing and selling of products and services, innovation, attractive pricing, and cost management, all of which will involve significant expenses.

Joint ventures, mergers, acquisitions and strategic alliances in the wireless sector have resulted in and are expected to result in larger competitors competing for a limited number of customers. The two largest national wireless communicationcommunications services providers currently serve a significant percentage of all wireless customers and hold significant spectrum and other resources. Our largest competitors may be able to enter into exclusive handset, device, or content arrangements, execute pervasive advertising and marketing campaigns, or otherwise improve their cost position relative to ours. In addition, refusal of our large competitors to provide critical access to resources and inputs, such as roaming services on reasonable terms could improve their position within the wireless broadband mobile services industry.

We face intense and increasing competition from other service providers as industry sectors converge, such as cable, telecom services and content, satellite, and other service providers. Companies like Comcast and AT&T (and AT&T’s proposed acquisition(with acquisitions of DirecTV and Time Warner, Inc.) will have the scale and assets to aggressively compete in a converging industry. Verizon, through theits acquisitions of AOL, Inc. and Yahoo! Inc. is also a significant competitor focusing on premium content offerings to diversify outside of core wireless. Further, some of our competitors now provide content services in addition to voice and

We will need to acquire additional spectrum in order to continue our customer growth, expand and deepen our coverage, maintain our quality of service, meet increasing customer demands, and deploy new technologies. We will be at a competitive disadvantage and possibly experience erosion in the quality of service in certain marketsgeographic areas if we fail to gain access to necessary spectrum before reaching network capacity. As a result, we are actively seeking to make additional investment in spectrum, which could be significant.

The continued interest in, and acquisition of, spectrum by existing carriers and others may reduce our ability to acquire and/or increase the cost of acquiring spectrum in the secondary market or negatively impact our ability to gain access to spectrum through other means, including government auctions. We may need to enter into spectrum sharing or leasing arrangements, which are subject to certain risks and uncertainties and may involve significant expenditures. Gaining access to the spectrum we won in the FCC 600 MHz auction in 2017 may take up to three years or more. Any material delay could adversely impact our ability to implement our plans and efforts to improve our network. In addition, our return on investment in spectrum depends on our ability to attract additional customers and to provide additional services and usage to existing customers. As a result, the return on any investment in spectrum that we make may not be as much as we anticipate or take longer than expected. Additionally, the FCC may not be able to provide sufficient additional spectrum to auction or we may be unable to secure the spectrum we need in any auction we may elect to participate in or in the secondary market, on favorable terms or at all.

The FCC may impose conditions on the use of new wireless broadband mobile spectrum that may negatively impact our ability to obtain spectrum economically or in appropriate configurations or coverage areas. Additional conditions that may be imposed by the FCC include heightened build-out requirements, limited license terms or renewal rights, and clearing obligations that may make it less attractive or less economical to acquire spectrum. In addition, rules may be established for future government

spectrum auctions that may negatively impact our ability to obtain spectrum economically or in appropriate configurations or coverage areas.

If we cannot acquire needed spectrum from the government or otherwise, if competitors acquire spectrum that will allow them to provide services competitive with our services, or if we cannot deploy services over acquired spectrum on a timely basis without burdensome conditions, at reasonable cost, and while maintaining network quality levels, then our ability to attract and retain customers and our associatedbusiness, financial condition and operating results could be materially adversely affected.

Significant technological changes continue to impact the communications industry. In general, these technological changes enhance communications and enable a broader array of companies to offer services competitive with ours. In order to grow and remain competitive with new and evolving technologies in our industry, we will need to adapt to future changes in technology, continually invest in our network, increase network capacity, enhance our existing offerings, and introduce new offerings to address our current and potential customers’ changing demands. Enhancing our network, such as deployingincluding our 5G network, is subject to risk from equipment changes and migration of customers from existing spectrum bandsolder technologies and the potential inability to secure mid-band 5G spectrum that is necessary to deployadd capacity to advanced technologies. Adopting new and sophisticated technologies may result in implementation issues such as scheduling and supplier delays, unexpected or increased costs, technological constraints, regulatory permitting issues, customer dissatisfaction, and other issues that could cause delays in launching new technological capabilities, which in turn could result in significant costs or reduce the anticipated benefits of the upgrades. In general, the development of new services in the wireless telecommunications industry will require us to anticipate and respond to the continuously changing demands of our customers, which we may not be able to do accurately or timely. If our new services fail to retain or gain acceptance in the marketplace or if costs associated with these services are higher than anticipated, this could have a material adverse effect on our business, financial condition and operating results.

Our business, like that of most retailers and wireless companies, involves the receipt, storage, and transmission of our customers’ confidential information, including sensitive personal information and payment card information, confidential information about our employees and suppliers, and other sensitive information about our Company, such as our business plans, transactions and intellectual property (“confidential information”Confidential Information”). Unauthorized access to confidential informationConfidential Information may be difficult to anticipate, detect, or prevent, particularly given that the methods of unauthorized access constantly change and evolve. We may experienceare subject to the threat of unauthorized access or distributiondisclosure of confidential informationConfidential Information by state-sponsored parties, malicious actors, third parties or employees, errors or breaches by third partythird-party suppliers, or other breaches of security incidents that could compromise the confidentiality and integrity of confidentialConfidential Information. In August 2018 and November 2019, we notified affected customers of incidents involving unauthorized access to certain customer information and such(not involving credit card information, financial data, social security numbers or passwords). While we do not believe these security incidents were material, we expect to continue to be the target of cyber-attacks, data breaches, canor security incidents, which may in the future have a materiallymaterial adverse effect on our business, or damage our reputation.reputation, financial condition, and operating results.

Cyber-attacks, such as denial of service and other malicious attacks, could disrupt our internal systems and applications, impair our ability to provide services to our customers, and have other adverse effects on our business and that of others who depend on our services. As a telecommunications carrier, we are considered a critical infrastructure provider and therefore may be more likely to be the target of such attacks. Such attacks against companies may be perpetrated by a variety of groups or persons, including those in jurisdictions where law enforcement measures to address such attacks are ineffective or unavailable, and such attacks may even be perpetrated by or at the behest of foreign governments.

In addition, we provide confidential, proprietary and personal information to third-party service providers when it is necessary to pursueas part of our business objectives. We and ouroperations. These third-party service providers have been subject toexperienced data breaches and other attacks that included unauthorized access to confidential informationConfidential Information in the past, includingand face security challenges common to all parties that collect and process information. Past data breaches include a breach atof the networks of one of our credit checkdecisioning providers in September 2015, induring which a subset of records containing current and potential customer information was compromisedacquired by an external party.

Our procedures and safeguards to prevent unauthorized access to sensitive data and to defend against attacks seeking to disrupt our services must be continually evaluated and revised to address the ever-evolving threat landscape. We cannot make assurances that all preventive actions taken will adequately repel a significant attack or prevent information security breaches or the misuses of data, unauthorized access by third parties or employees, or exploits against third-party supplier environments. If

we or our third-party suppliers are subject to such attacks or security breaches, we may incur significant costs or other material financial impacts, which may not be covered by, or may exceed the coverage limits of, our cyber insurance, be subject to regulatory investigations, sanctions and private litigation, experience disruptions to our operations or suffer damage to our reputation. Any future cyber-attacks, data breaches, or security breachesincidents may materially adversely affecthave a material adverse effect on our business, financial condition, and operating results.

To be successful, we must provide our customers with reliable, trustworthy service and protect the communications, location, and personal information shared or generated by our customers. We rely upon both our systems and networks and the systems and networks of other providers and suppliers to provide and support our services and, in some cases, protect our customers’ information and our information. Failure of our or others’ systems, networks, or infrastructure may prevent us from providing reliable service or may allow for the unauthorized use of or interference with our networks and other systems or for the compromise of customer information. Examples of these risks include:

Such events could cause us to lose customers, lose revenue, incur expenses, suffer reputational damage, and subject us to litigation or governmental investigation. Remediation costs could include liability for information loss, repairing infrastructure and systems, and/or costs of incentives offered to customers. Our insurance may not cover, or be adequate to fully reimburse us for, costs and losses associated with such events.

The ongoing implementation may cause major system or business disruptions, or we may fail to implement the new billing system in its entirety or in a timely or effective manner. In addition, we or the third-party billing services supporting vendor may experience errors, cyber-attacks, or other operational disruptions that could negatively impact us and over which we may have limited control. Interruptions and/or failure of this new billing services system could disrupt our operations and impact our ability to provide or bill for our services, retain customers, attract new customers, or negatively impact overall customer experience. Any occurrence of the foregoing could cause material adverse effects on our operations and financial condition, material weaknesses in our internal control over financial reporting, and reputational damage.

We depend heavily on suppliers, service providers, their subcontractors and other third parties in order for us to efficiently operate our business. Due to the complexity of our business, it is not unusual for multiple vendors located in multiple locationsto engage a diverse set of suppliers to help us to develop, maintain, and troubleshoot products and services such as network components, software development services, and billing and customer service support. OurSome of our suppliers may provide services from outside of the United States, which carries associated additional regulatory and legal obligations. We commonly rely upon theon suppliers to provide us with contractual assurances and to disclose accurate information regarding risks associated with their provision of products or services in accordance with our expectations

policies and standards, such asincluding our supplier codeSupplier Code of conductConduct and our third party-risk management standards. Failurepractices. The failure of suchour suppliers to comply with our expectations and standardspolicies could have a material adverse effect on our business, financial condition, and operating results.

There are multiple sources forMany of the types of products and services we purchase or use.use are available through multiple sources and suppliers. However, there are a limited number of suppliers forwho can support or provide billing services, voice and data communications transport services, network infrastructure, equipment, handsets, other devices, and payment processing services, among other products and services. Disruptions or failure of such suppliers to adequately perform could have a material adverse effect on our business, financial condition, and operating results.

In the past, our suppliers, contractors, service providers and third-party retailerstheir subcontractors may not have always performed at the levels we expected or at the levels required by their contracts. Our business could be severely disrupted if keycritical suppliers contractors,or service providers or third-party retailers fail to comply with their contracts or become unable to continue provision of services or supplies. Our business could also be disrupted if we experience delays or service degradation during any transition to a new outsourcing provider or other supplier or if we are required to replace the supplied products or services with those from another source, especially if the replacement becomes necessary on short notice. Any such disruptions could have a material adverse effect on our business, financial condition, and operating results.

Our business, financial condition, and operating results are sensitive to changes in general economic conditions, including interest rates, consumer credit conditions, consumer debt levels, consumer confidence, rates of inflation (or concerns about deflation), unemployment rates, economic growth, energy costs, and other macro-economic factors. Difficult, or worsening, general economic conditions could have a material adverse effect on our business, financial condition, and operating results.

Market volatility, political and economic uncertainty, and weak economic conditions, such as a recession or economic slowdown, may materially adversely affect our business, financial condition, and operating results in a number of ways. Our services and device financing plans are available to a broad customer base, a significant segment of which may be more vulnerable to weak economic conditions.conditions, particularly our subprime customers. We may have greater difficulty in gaining new customers within this segment, and existing customers may be more likely to terminate service and default on device financing plans due to an inability to pay.

Weak economic conditions and credit conditions may also adversely impact our suppliers, dealers, and dealers,MVNOs, some of which have filedmay file for or may be considering bankruptcy, or may experience cash flow or liquidity problems, or aremay be unable to obtain or refinance

In addition, instability in the global financial markets could lead to periodic volatility in the credit, equity, and fixed income markets. This volatility could limit our access to the credit markets, leading to higher borrowing costs or, in some cases, the inability to obtain financing on terms that are acceptable to us or at all.

The agreements governing our indebtedness and other financing arrangements impose significant operating and financial restrictions on us. These restrictions, subject in certain cases to customary baskets, exceptions, and incurrence-based ratio tests, may limit our or our subsidiaries’ ability to pursue strategic business opportunities and engage in somecertain transactions, including the following:

These restrictions could limit our ability to obtain debt financing, engage in share repurchases, refinance or pay principal on our outstanding indebtedness, complete acquisitions for cash or indebtedness or react to business, economic, market and industry conditions and other changes in our operating environment or the economy. Any future indebtedness that we incur may contain similar or more restrictive covenants. Any failure to comply with the restrictions of our debt agreements and other financing arrangements may result in an event of default under these agreements, which in turn may result in defaults or acceleration of obligations under these agreements and other agreements, giving our lenders the right to terminate any commitments they had made to provide us with further funds and to require us to repay all amounts then outstanding.outstanding plus any interest, fees, penalties or premiums, which may require us to sell certain assets securing indebtedness. Any of these events wouldcould have a material adverse effect on our business, financial condition, and operating results.

Our ability to make payments on our debt, to repay our existing indebtedness when due, and to fund our capital-intensive business and operations, and to make significant planned capital expenditures will depend on our ability to generate cash in the future, which is in turn subject to the operational risks described elsewhere in this report. Our debt service obligations could have material adverse effects on our business, financial condition, and operating results, including by:

Some of our debt also has a floating rate of interest linked to various indices. If the change in indices result in interest rate increases, debt service requirements will increase, which could adversely affect our cash flow and operating results. In addition, anyAny hedging agreements we have and may continue to enter into to limit our exposure to interest rate increases or foreign currency fluctuations may not offer complete protection from this risk,these risks or may be unsuccessful, and consequently may effectively increase the interest rate we pay on our debt or the exchange rate with respect to such debt, and any portion not subject to such hedging agreements would have full exposure to interest rate increases.increases or foreign currency fluctuations, as applicable.

Under Section 404 of the Sarbanes-Oxley Act of 2002, we along with our independently registered public accounting firm are required to report on the effectiveness of our internal control over financial reporting. We rely heavily on IT systems and, manual and automated processes as an important part of our internal controls in order to operate, transact, and otherwise manage our business, as well as provide

inaccurate financial statements, inaccurate disclosures, or failure to prevent fraud. If we or our independent registered public accounting firm were unable to conclude that we have effective internal control over financial reporting, investor confidence regarding our financial statements and our business could be materially adversely affected.

Our operating costs could increase substantially as a result of fraud, including any fraud related to device financing, customer credit card, subscription,subscriptions, or dealer fraud.dealers. If our fraud detection strategies and processes are not successful in detecting and controlling fraud, whether directly or by way of the systems, processes, and operations of third parties such as national retailers, dealers, and others, the resulting loss of revenue or increased expenses could have a material adverse effect on our financial condition and operating results.

We may pursue acquisitions of, investments in or mergers with businesses, technologies, services and/or products that complement or expand our business. Some of these potential transactions could be significant relative to the size of our business and operations. Any such transaction would involve a number of risks and could present financial, managerial and operational challenges, including:

For any or all of these reasons, our pursuit of an acquisition, investment, or merger may have a material adverse effect on our business, financial condition, and operating results.

The FCC regulates the licensing, construction, modification, operation, ownership, sale, and interconnection of wireless communications systems, as do some state and local regulatory agencies. In particular, the FCC imposes significant regulation on licensees of wireless spectrum with respect to how radio spectrum is used by licensees, the nature of the services that licensees may offer and how the services may be offered, and the resolution of issues of interference between spectrum bands. Additionally, the FTC and other federal and state agencies have asserted that they have jurisdiction over some consumer protection, and elimination and prevention of anticompetitive business practices with respect to the provision of wireless products and services. We are subject to regulatory oversight by various federal, state and local agencies, as well as judicial review and actions, on issues related to the wireless industry that include, but are not limited to: roaming, interconnection, spectrum allocation and licensing, facilities siting, pole attachments, intercarrier compensation, Universal Service Fund (“USF”), net neutrality, 911 services, consumer protection, consumer privacy, and cybersecurity. We are also subject to regulations in connection with other aspects of our business, including handset financing and insurance activities.

We cannot assure you that the FCC or any other federal, state or local agencies will not adopt regulations or take enforcement or other actions that would adversely affect our business, impose new costs, or require changes in current or planned operations. For example, under the Obama administration, the FCC established new net neutrality and privacy regimes that applied to our operations. Both sets of rules potentially subjected some of our initiatives and practices to more burdensome requirements and heightened scrutiny by federal and state regulators, the public, edge providers, and private litigants regarding whether such initiatives or practices are compliant. While the FCC rules are now largely rolled back under the Trump administration, some state legislatorsstates and regulatorsother jurisdictions have enacted, or are seeking to replace them with stateconsidering enacting, laws in these areas (including for example the CCPA cited below), perpetuating the risk and uncertainty regarding the regulatory environment and compliance around these issues.

In addition, states are increasingly focused on the quality of service and support that wireless communicationcommunications services providers provide to their customers and several states have proposed or enacted new and potentially burdensome regulations in this area. We also face potential investigations by, and inquiries from or actions by state Public Utility Commissions.public utility commissions. We also cannot assure you that Congress will not amend the Communications Act, from which the FCC obtains its authority, and which serves to limit state authority, or enact other legislation in a manner that could be adverse to our business.

Failure to comply with applicable regulations could have a material adverse effect on our business, financial condition and operating results. We could be subject to fines, forfeitures, and other penalties (including, in extreme cases, revocation of our spectrum licenses) for failure to comply with FCC or other governmental regulations, even if any such non-compliance was unintentional. The loss of any licenses, or any related fines or forfeitures, could adversely affect our business, financial condition, and operating results.

We are regularly involved in a number of legal proceedings before various state and federal courts, the FCC, the FTC, other federal agencies, and state and local regulatory agencies, including state attorneys general. Such legal proceedings can be complex, costly, and highly disruptive to our business operations by diverting the attention and energiesenergy of management and other key personnel. The assessment of the outcome of legal proceedings, including our potential liability, if any, is a highly subjective process that requires judgments about future events that are not within our control. The amounts ultimately received or paid upon settlement or pursuant to final judgment, order or decree may differ materially from amounts accrued in our financial statements. In addition, litigation or similar proceedings could impose restraints on our current or future manner of

doing business. Such potential outcomes including judgments, awards, settlements or orders could have a material adverse effect on our business, financial condition and operating results.

The financing of devices, through our EIP and JUMP! On Demand programs, has expanded our regulatory compliance obligations. Failure to remain compliant with applicable regulations, may increase our risk exposure in the following areas:

Failure to comply with applicable regulations and the realization of any of these risks could have a material adverse effect on our business, financial condition, and operating results.

We rely on a combination of patent, service mark, trademark, and trade secret laws and contractual restrictions to establish and protect our proprietary rights, all of which offer only limited protection. The steps we have taken to protect our intellectual property may not prevent the misappropriation of our proprietary rights. We may not have the ability in certain jurisdictions to adequately protect intellectual property rights. Moreover, others may independently develop processes and technologies that are competitive to ours. Also, we may not be able to discover or determine the extent of any unauthorized use of our proprietary rights. Unauthorized use of our intellectual property rights may increase the cost of protecting these rights or reduce our revenues. We cannot be sure that any legal actions against such infringers will be successful, even when our rights have been infringed. We cannot assure you that our pending or future patent applications will be granted or enforceable, or that the rights granted under any patent that may be issued will provide us with any competitive advantages. In addition, we cannot assure you that any trademark or service mark registrations will be issued with respect to pending or future applications or will provide adequate protection of our brands. We do not have insurance coverage for intellectual property losses, and as such, a charge for an anticipated settlement or an adverse ruling awarding damages represents an unplanned loss event. Any of these factors could have a material adverse effect on our business, financial condition, and operating results.

Third parties may claim we infringe their intellectual property rights. We are a defendant in numerous intellectual property lawsuits, including patent infringement lawsuits, which exposes us to the risk of adverse financial impact either by way of significant settlement amounts or damage awards. As we adopt new technologies and new business systems and provide customers with new products and/or services, we may face additional infringement claims. These claims could require us to cease certain activities or to cease selling relevant products and services. These claims can be time-consuming and costly to defend, and divert management resources, and expose us to significant damages awards or settlements, any or all of which could have a material adverse effect on our operations and financial condition. In addition to litigation directly involving our Company, our vendors and suppliers can be threatened with patent litigation and/or subjected to the threat of disruption or blockage of sale, use, or importation of products, posing the risk of supply chain interruption to particular products and associated services which could have a material adverse effect on our business, financial condition and operating results.

In connection with the products and services we sell, we calculate, collect, and remit various federal, state, and local taxes, surchargesfees and regulatory feescharges (“tax” or “taxes”) to numerous federal, state and local governmental authorities, including federal USF contributions and common carrier regulatory fees. In addition, we incur and pay state and local taxes and fees on purchases of goods and services used in our business.

Tax laws are dynamic and subject to change as new laws are passed and new interpretations of the law are issued or applied. In many cases, the application of existing, newly enacted or amended tax laws (including(such as the recently enactedU.S. Tax Cuts and Jobs Act of 2017 in the United States) is2017) may be uncertain and subject to differing interpretations, especially when evaluated against new technologies and telecommunications services, such as broadband internet access and cloud related services. Changes in tax laws could also impact revenue reported on tax inclusive plans.

In the event that we have incorrectly described, disclosed, determined, calculated, assessed, or remitted amounts that were due to governmental authorities, we could be subject to additional taxes, fines, penalties, or other adverse actions, which could materially impact our business, financial condition and operating results. In the event that federal, state, and/or local municipalities were to significantly increase taxes on our network, operations, or services, or seek to impose new taxes, it could have a material adverse effect on our business, financial condition and operating results.

Our existing wireless licenses are subject to renewal upon the expiration of the 10-year or 15-year period for which they are granted. Historically, the FCC has approved our license renewal applications. However, the Communications Act provides that licenses may be revoked for cause and license renewal applications denied if the FCC determines that a renewal would not serve the public interest. In addition, our licenses are subject to our compliance with the terms set forth in the agreement

We do not manufacture the devices or other equipment that we sell, and we depend on our suppliers to provide defect-free and safe equipment. Suppliers are required by applicable law to manufacture their devices to meet certain governmentally imposed safety criteria. However, even if the devices we sell meet the regulatory safety criteria, we could be held liable with the equipment manufacturers and suppliers for any harm caused by products we sell if such products are later found to have design or manufacturing defects. We generally seek to enter into indemnification agreements with the manufacturers who supply us with devices to protect us from losses associated with product liability, but we cannot guarantee that we will be fully protected in whole or in part against all losses associated with a product that is found to be defective.

Additionally, there are safety risks associated with the use of wireless devices while operating vehicles or equipment. Concerns over any of these risks and the effect of any legislation, rules or regulations that have been and may be adopted in response to these risks could limit our ability to sell our wireless services.

Deutsche TelekomDT beneficially owns and possesses majority voting power of the fully diluted shares of our common stock.

rules, and are not subject to NASDAQ requirements that would otherwise require us to have a majority of independent directors, a nominating committee composed solely of independent directors or a compensation committee composed solely of independent directors. Accordingly, our stockholders will not be afforded the same protections generally as stockholders of other NASDAQ-listed companies with respect to corporate governance for so long as we rely on these exemptions from the corporate governance requirements.

In addition, our certificate of incorporation and the Stockholder’s Agreement restrict us from taking certain actions without Deutsche Telekom’sDT’s prior written consent as long as Deutsche TelekomDT beneficially owns 30% or more of the outstanding shares of our common stock, including:

These restrictions could prevent us from taking actions that our Board of Directors may otherwise determine are in the best interests of the Company and our stockholders or that may be in the best interests of our other stockholders.

Deutsche TelekomDT effectively has control over all matters submitted to our stockholders for approval, including the election or removal of directors, changes to our certificate of incorporation, a sale or merger of our Company and other transactions requiring stockholder approval under Delaware law. Deutsche Telekom’sDT’s controlling interest may have the effect of making it more difficult for a third party to acquire, or discouraging a third party from seeking to acquire, the Company. Deutsche TelekomDT may have strategic, financial, or other interests different from our other stockholders, including as the holder of a substantial amount of our indebtedness and as the counter-party in a number of commercial arrangements, and may make decisions adverse to the interests of our other stockholders.

In addition, we license certain trademarks from Deutsche Telekom,DT, including the right to use the trademark “T-Mobile” as a name for the Company and our flagship brand, under a trademark license agreement between Deutsche Telekom and the Company.with DT. As described in more detail in our proxy statement under the heading “Transactions with Related Persons and Approval”,Approval,” we are obligated under the trademark license agreement to pay Deutsche TelekomDT a royalty in an amount equal to 0.25%, which we refer to as the royalty rate, of the net revenue (as defined in the trademark license) generated by products and services sold by the Companywe sell under the licensed trademarks. However, theThe trademark license agreement includes a royalty rate adjustment mechanism that will occurwould have occurred in early 2018 and potentially resultresulted in a new royalty rate effective in January 2019. The license agreement includes a royalty rate adjustment mechanism that has been postponed until the conclusion of the proposed Sprint Merger. The current royalty rate will remain effective until that time. The royalty rate under the license agreement will be adjusted retroactively if the Business Combination Agreement is terminated. We also have the right to terminate the trademark license upon one year’s prior notice. An increase in the royalty rate or termination of the trademark license could have a material adverse effect on our business, financial condition and operating results.

We cannot predict the effect, if any, that market sales of shares or the availability of shares of our common stock will have on the prevailing trading price of our common stock from time to time. Sales or issuances of a substantial number of shares of our common stock could cause our stock price to decline and could result in dilution of your shares.

We and Deutsche TelekomDT are parties to the Stockholder’s Agreement pursuant to which Deutsche TelekomDT is free to transfer its shares in public sales without notice, as long as such transactions would not result in the transferee owning 30% or more of the outstanding shares of our common stock. If a transfer would exceed the 30% threshold, it is prohibited unless the transferee makes a binding offer to

purchase all of the other outstanding shares on the same price and terms. The Stockholder’s Agreement does not otherwise impose any other restrictions on the sales of common stock by Deutsche Telekom.DT. Moreover, we have filedmay be required to file a shelf registration statement with respect to the common stock and certain debt securities held by Deutsche Telekom,DT, which would facilitate the resale by Deutsche TelekomDT of all or any portion of the shares of our common stock it holds. The sale of shares of our common stock by Deutsche TelekomDT (other than in transactions involving the purchase of all of our outstanding shares) could significantly increase the number of shares available in the market, which could cause a decrease

The trading prices of the securities of communications companies historically have been highly volatile, and the trading price of our common stock may be subject to wide fluctuations. Our stock price may fluctuate in reaction to a number of events and factors that may include, among other things:

In addition, the stock market has been volatile in the recent past and has experienced significant price and volume fluctuations, which may continue for the foreseeable future. This volatility has had a significant impact on the trading price of securities issued by many companies, including companies in the communications industry. These changes frequently occur irrespective of the operating performance of the affected companies. Hence, the trading price of our common stock could fluctuate based upon factors that have little or nothing to do with our business, financial condition and operating results.

We have never paid or declared any cash dividends on our common stock, and we do not intend to declare or pay any cash dividends on our common stock in the foreseeable future. Our credit facilities and the indentures and supplemental indentures

governing our long-term debt to affiliates and third parties contain covenants that, among other things, restrict our ability to declare or pay dividends on our common stock. We currently intend to use future earnings, if any, to invest in our business and to fund our existingpreviously authorized stock repurchase program.program if the Merger fails to close.

None.

As of December 31, 2017,2019, our significant properties that we primarily leasedlease and were useduse in connection with switching centers, data centers, call centers and warehouses were as follows:

As of December 31, 2017,2019, we primarily leased:

None.

Our common stock is traded on the NASDAQ Global Select Market under the symbol “TMUS.” T-Mobile was added to the S&P 500 Index effective prior to the open of trading on July 15, 2019. We were added to the S&P 500 GICS (Global Industry Classification Standard) Wireless Telecommunication Services Sub-Industry index. As of December 31, 2017,2019, there were 269258 registered stockholders of record of our common stock, but we estimate the total number of stockholders to be much higher as a number of our shares are held by brokers or dealers for their customers in street name.

The graph below compares the five-year cumulative total returns of T-Mobile, the S&P 500 index, the NASDAQ Composite index and the Dow Jones US Mobile Telecommunications TSM index. The graph tracks the performance of a $100 investment, with the reinvestment of all dividends, from December 31, 20122014 to December 31, 2017. For periods prior to2019.

The five-year cumulative total returns of T-Mobile, the closing ofS&P 500 index, the business combination with MetroPCS, our stock price performance representsNASDAQ Composite index and the stock price of MetroPCS, adjusted to reflectDow Jones US Mobile Telecommunications TSM index, as illustrated in the 1-for-2 reverse stock split effected on April 30, 2013.graph above, are as follows: