TMUS 10-K & 10-Q changes, risk factors and insider trading

We operate in a highly competitive industry. If we are unable to attract and retain customers, our business, financial condition, and operating results wouldcould be negatively affected.

The wireless communications servicestelecommunications industry is highly competitive. As the industry reaches saturation, competition in all market segments, including prepaid, postpaid, enterprise and government customers will likely further intensify, putting pressure on pricing and/or margins for us and all our competitors. Our ability to attract and retain customers will depend on multiple factors, such as network quality and capacity, customer service excellence, effective marketing strategies, competitive pricing, compelling value propositions, and distribution and logistics capabilities. Additionally, targeted marketing approaches for diversea broad spectrum of customer segments, coupled with continuous innovation in products and services, are essential for retaining and expanding our customer base. If we are unable to successfully differentiate our services from those of our competitors, it would adversely affect our competitive position and ability to grow our business.

We have seen and expect to continue to see intense competition in all market segments from traditional Mobile Network Operators (“MNOs”), such as AT&T and Verizon, who have each invested heavily in spectrum, their wireless networks, and services and device promotions, and DISH, as it continues to build out its wireless network and roll out services.promotions. Numerous other regional MNOs and MVNOs offering wireless services may also compete with us in some markets, including cable providers, such as Comcast, Charter, Cox, and Altice, as they continue to diversify their offerings to include wireless services offered under MVNO agreements. As new products and services emerge, we may also beface forcedcompetition to compete againstfrom non-traditional competitors from outside of the wireless communications services industry, such asincluding satellite providers,providers offering similar connectivity services using alternative technologies.

In the market for broadband services, traditional cable providers, AT&T, Verizon, and other players such as satellite and fiber providers, all compete for customers. To complement our fixed wireless service, we have agreed to enterentered into joint venture agreements aimed at establishing a robust fiber wireline network in certain geographic regions that we believe will complement our fixed wireless services in those areas. However, these partnerships also involve inherent risks. See “Any acquisition, divestiture, investment, joint ventureventure, merger, or mergerdivestiture may subject us to significant risks, any of which may harm our business” for further discussionsdiscussion of such risks.

If we are unable to compete effectively in attracting and retaining customers in markets where we operate, it could negatively impactaffect our business, financial condition, and operating results.

We have experienced criminal cyberattacks and may experience disruption,disruptions, data loss and other security breaches, whether directly or indirectly through third parties whose products and services we rely on in operating our business.

Our business involves the receipt, storage, and transmission of confidential information about our customers, such as sensitive personal, accountaccount, and payment information, confidential information about our employees and suppliers, and other sensitive information about our Company, such as our business plans, transactions, financial information, and intellectual property (collectively, “Confidential Information”). Additionally, to offer services to our customers and operate our business, we utilize several applications and systems, including those we own and operate, such as our wireless network, as well as others provided to us by third parties, such as cloud service providers and SaaS companies (collectively, “Systems”).

We are subject to persistent cyberattacks and threats to our business from bad actors seeking to gain unauthorized access to Confidential Information and compromise Systems to undermine availability or integrity. They are perpetrated by a variety of groups and persons, including nation state-sponsored parties, malicious actors, employees, contractors, orand other unrelated third parties. Some actors reside in jurisdictions where law enforcement measures to address such attacks are ineffective or unavailable.

Cyberattacks against companies like ours are increasing in frequency and scope of potential harm over time, and the methods used to gain unauthorized access constantly evolve, making it increasingly difficult to anticipate, prevent, and detect incidents successfully in every instance. In some cases, these bad actors exploit bugs, errors, misconfigurations or other vulnerabilities in our Systems to obtain Confidential Information. In other cases, these bad actors obtain unauthorized access to Confidential Information by exploiting insider access or utilizing log inlogin credentials taken from our customers, employees, or third-party providers through credential harvesting, social engineering or other means. Other bad actors aim to cause serious operational disruptions to our business and Systems through ransomware or distributed denial of servicesservice attacks. Moreover, the amount and scope of insurance that we maintain against losses resulting from any such incidents or security breaches may not be sufficient to cover our losses or otherwise adequately compensate us for any disruptions to our business that may result.

Although we regularly work to identify, tracktrack, and remedy any security vulnerabilities, given the complex nature of our Systems and the tools that are available to us, we may be unable to identify vulnerabilities in a timely manner, or to apply patches or compensating measures that address such vulnerabilities, before bad actors can exploit them. The exploitation of a security vulnerability before patches or measures are applied could materially compromise Confidential Information and Systems.

In addition, we routinely rely upon third-party providers whose products and services are used in our business. These third-party providers have experienced, and will continue to experienceexperience, cyberattacks that involve attempts to exposeaccess our Confidential Information and/or to create operational risk that could materially and adversely affect our business, and these providers also face other security challenges common to all parties that collect and process information. Additionally, our Systems include components from third parties or fourth parties we do not control and may have compromises, defects, flaws, or design errors unknown to us.

As a result of the previously disclosed cyberattacks in August 2021 and January 2023, we incurred significant costs in connection with, among other things, responding to and resolving mass arbitration claims, multiple class action lawsuitslawsuits, and an FCC investigation. For more information on the foregoing, see “– Contingencies and Litigation – Litigation and Regulatory Matters” in Note 18 – Commitments and Contingencies of the Notes to the Consolidated Financial Statements.

In addition to the August 2021 cyberattack and the January 2023 cyberattack, we have experienced unrelatedunrelated, non-material incidents involving unauthorized access to certain Confidential Information and Systems. Typically, these incidents have involved attempts to commit fraud by taking control of a customer’s phone line, often by exploiting insider access or using compromised credentials. In other cases, the incidents have involved unauthorized access to certain of our customers’ private information, including payment information, financial data, social security numbers or passwords, and our intellectual property. Some of these incidents have occurred at third-party providers, including third parties who provide us with various Systems and others who sell our products and services through retail locations or take care of our customers.

Our procedures and safeguards to prevent unauthorized access to Confidential Information and to defend against cyberattacks seeking to disrupt our operations must be continually evaluated and enhanced to address the ever-evolving threat landscape and changing cybersecurity regulations, including while we adapt complex digital transformation efforts. These preventative actions require the investment of significant resources and management time and attention. Additionally, we do not have control of the cybersecurity systems, breach prevention, and response protocols of our third-party providers, including through our cybersecurity programs or policies. While T-Mobile may have contractual rights to assess the effectiveness of many of our providers’ systems and protocols, we do not have the means to always know or assess the effectiveness of all of our providers’ systems and controls. We cannot provide any assurances that actions taken by us, or our third-party providers, including through our cybersecurity programs or policies, will adequately repel a significant cyberattack or prevent or substantially mitigate the impacts of cybersecurity breaches or misuses of Confidential Information, unauthorized access to our networks or Systems or exploits against third-party environments, or that we, or our third-party providers, will be able to effectively identify, investigate, and remediate such incidents in a timely manner or at all. We expect to continue to be the target of cyberattacks, given the nature of our business, and we expect the same with respect to our third-party providers. We also expect that threat actors will continue to gain sophistication including in the use of tools and techniques (such as AI) that are specifically designed to circumvent security controls, evade detection, and obfuscate forensic evidence, making it more challenging for us to identify, investigateinvestigate, and recover from future cyberattacks in a timely and effective manner. The continued development and integration of AI in our and our third-party providers’ operations, products and services is expected to pose new, additional, and unknown cybersecurity risks. In addition, we have acquired and continue to acquire companies with cybersecurity vulnerabilities or unsophisticated security measures, which exposesexpose us to significant cybersecurity, operational, and financial risks. If we fail to protect Confidential Information or to prevent operational disruptions from future cyberattacks, there may be a material adverse effect on our business, reputation, financial condition, cash flows, and operating results.

If we fail to timely adopt and effectively deploy emerging network technologies,technologies in a timely and effective manner, our competitive position could erode, which may adversely affect our business, financial condition, and operating results.

Our competitive advantage and reputation depend on our ability to provide industry-leading network coverage, speed, and reliability. While we have established a leadership position in 5G, the communicationstelecommunications industry evolves rapidly, and emerging technologies –technologies, such as AI-driven Radio Access Networks (“AI-RAN”) and the potential transition to 6G –6G, may redefine network standards and increase customer expectations. Our competitors may seek to differentiate through marketing, brand positioning, or third-party recognition as leaders in network performance, coverage, or reliability. To stay ahead, we continue to drive improvements in the 5G network, including our nationwide 5G standalone network and deployment of 5G Advanced features, and are investing in strategic collaborations with third parties, such as AI-RAN partnerships, to develop technologies that are intended to advance our network capabilities. Despite these efforts, we may encounter technical challenges, regulatory hurdles, supply chain constraints, or unexpected delays in developing and deploying new network technologies. If we fail to anticipate market trends, efficiently integrate innovative solutions into our network, or maintain the quality and reliability of our network, our market share and competitive standing could erode, adversely impactingaffecting our businessbusiness, financial condition, and operating results.

We are engaged in complex digital transformation efforts intended to streamline operations, enhance customer experience, and improve our overall competitiveness. These initiatives involve integrating emerging and rapidly evolving technologies, reconfiguring internal processes, and implementing advanced data analytics and AI-driven tools, including those developed through our partnerships with a number ofseveral third-party providers. The successful execution of our planned transformation is subject to significant uncertainties. For example, we may face challenges in harmonizing complex system architectures, integrating new platforms with legacy infrastructure, and managing large volumes of data from disparate sources. We must also maintain rigorous data security and privacy safeguards, ensure our AI-driven solutions comply with evolving regulatory standards, and mitigate potential issues such as algorithmic bias or unintended operational disruptions. Additionally, implementing these digital solutions often requires substantial capital and operational expenditures, extensive employee training, specialized skill sets that may be difficult to source, and close coordination with multiple third-party vendors and partners. If we fail to execute these initiatives effectively, our ability to realize the intended benefits of digital transformation may be compromised. Even if we successfully deploy these capabilities, customer adoption and employee acceptance may be slower than anticipated, diminishing the expected improvements to efficiency, service quality, or revenue generation. This could materially and adversely affect our competitive position, financial performance, and brand reputation.

Our future success depends in substantial part on our ability to attract, recruit, hire, motivate, develop, and retain talented personnel possessing the qualifications, experiences,experience, capabilities and skills we need for all areas of our organization, including our CEO and members of our senior leadership team. Succession planning to ensure the effective transfer of knowledge and a seamless transition when key personnel depart is also important to our long-term success. On November 1, 2025, G. Michael Sievert retired as our Chief Executive Officer while continuing to serve as Vice Chairman of the Company and Vice Chairman of our Board of Directors, and Srinivasan Gopalan began serving as our President and Chief Executive Officer. We also announced several leadership changes. In addition, we began to implement enterprise-wide restructurings in 2025. If we are unable to effectively manage the CEO transition, the leadership changes and other restructuring changes, our ability to execute our business strategies and to retain key executives and talent could be adversely affected. Additionally, as we continue to make significant investments in new technologies and new business areas, we are increasingly dependent on being able to hire and retain technically skilled employees, including those with expertise in AI and machine learning.

Both external factors, such as fluctuations in economic and industry conditions, changes in U.S. immigration policies, regulatory changes, political forcesforces, and the competitive landscape, and internal factors, such as employee tolerance for changes in our corporate culture, organizational changes, limited remote working opportunities, and our compensation programs, may impactaffect our ability to effectively manage our workforce. Further, employee compensation and benefit costs may increase due to inflationary pressures, and if our compensation does not keep up with inflation or with that of our competitors’,competitors, we may see increased employee dissatisfaction and departures or difficulty in recruiting new employees. If key employees depart or we are unable to recruit and integrate new employees successfully, our business could be negatively impacted.

We rely upon systems and networks – those of third-party suppliers and other providers, in addition to our own – to provide services to our customers. System, network, or infrastructure failures resulting from one of several potential causes may prevent us from providing reliable service or otherwise operateoperating our business. Examples of these risks include:

•physical damage, power surges or outages, equipment failure, or other service disruptions with respect to both our wireless and wirelinefiber networks, including those resulting from severe weather, storms, earthquakes, floods, hurricanes, wildfireswildfires, and other natural disasters, which may occur more frequently or with greater intensity as a result of global climate change, public health crises, terrorist attacks, political instability and volatility and acts of war;

We continue to acquire and deploy new spectrum to expand and deepen our 5G coverage, maintain our quality of service, meet increasing or changing customer demands, and deploy new technologies. In order toTo expand and differentiate our services from those of our competitors, we will continue to actively seek to make additional investments in new spectrum, which could be significant. However, we may be unable to secure the additional spectrum necessary to maintain or enhance our competitive position on favorable terms or at all.

The continued interest in acquiring spectrum by existing carriers and others, including satellite providers and speculators, may reduce our ability to acquire or renew spectrum holdings (such as 2.5Ghz600 MHz and 2.5 GHz), and/or may increase the cost of spectrum that is made available in the secondary markets and government auctions. Additionally, the FCC may be unable to make sufficient additional spectrum available for auction to meet the demand from all interested parties. As a result, any such spectrum that is made available at auction may be subject to heightened competition and priced beyond levels we are able or willing to pay.

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

Any acquisition, divestiture, investment, joint ventureventure, merger, or mergerdivestiture may subject us to significant risks, any of which may harm our business.

We have pursued and may continue to pursue additional acquisitions of, investments in, or joint ventures or mergers with, other companies, or the acquisition of spectrum, technologies, services, productsproducts, or other assets that we believe would complement or expand our business. For example, on August 1, 2025, we completed the acquisition (the “UScellular Acquisition”) of the UScellular Wireless Business (as defined below). We may also elect to divest some of our assets to third parties. Some of these potential transactions could be significant relative to the size of our business and operations. Any such transaction wouldtransactions involve a number of risks and could present financial, managerialmanagerial, and operational challenges, including:

•potential loss of talent during integration due to differences in culture, locations,location, or other factors;

•difficulties in effectively integrating (or supplanting) the financial, operationaloperational, and sustainability systems of the business involved in any such transaction into (or supplanting such systems with) our financial, operationaloperational, and sustainability reporting infrastructure and internal control framework in an effective and timely manner;

•risks of entering markets in which thewe Company hashave no or limited experience and where competitors have stronger market positions;

•potential exposure to material liabilities not discovered in the due diligence process or as a result of any litigation arising in connection with any such transaction;

•significant transaction-related expenses in connection with pursuing any such transaction, whether consummated or not;

•risks related to our ability to obtain any required regulatory approvals necessary to consummate any such transaction; and

•any business, technology, service, or product involved in any such transaction may significantly under-performunderperform relative to our expectations, and we may not achieve the benefits we expect from the transaction, which could, among other things,could also result in a write-down of goodwill and other intangible assets associated with such transaction.

We have entered intoformed joint venture agreementsventures aimed at establishing a robust fiber broadband networknetworks that complementscomplement our fixed wireless services. Once closed, differencesDifferences in views among the joint venture participants may result in delayed decisions or disputes. Operating through joint ventures in which we do not hold a majority or controlling ownership interest results in us having limited control over many decisions made with respect to the businesses of the joint ventures. We also cannot control the actions of our co-investors in our joint venture partners.ventures. These joint ventures may not be subject to the same requirements regarding internal controls and internal control over financial reporting that we follow. As a result, internal control problems may arise with respect to these joint ventures. Any of these risks could have a material adverse effect on our business, financial conditioncondition, and operating results of operations and could also affect our reputation.

Additionally, in connection with our merger (the “Sprint Merger”) with Sprint Corporation (“Sprint”) and related transactions, including the acquisition by DISH Network Corporation (“DISH”) of certain prepaid wireless business (the “Prepaid Transaction” and, collectively, the “Transactions”), we agreed to fulfill various government commitments (the “Government Commitments”), including, among others, extensive 5G network build-out, delivering high-speed wireless services to the vast majority of AmericansAmericans, and marketing our in-home fixed wireless product to households where spectrum capacity is sufficient, as well as commitments related to national security, pricing and availability of rate plans.security. These Government Commitments materially increased our compliance obligations and could result in additional expenses and/or penalties in the future. In connection with the Prepaid Transaction, we and DISH entered into certain arrangements, including a Master Network Services Agreement (the “MNSA”), pursuant to which we provide DISH, for a period of seven years, network services for certain end users and infrastructure mobile network operator services to assist in the access and integration of the DISH network.

Any failure to fulfill our obligations under the Government Commitments and the MNSA in a timely manner could result in substantial fines, penalties, or other legal and administrative actions, liabilities, and reputational harm.

Economic, politicalpolitical, and market conditions may adversely affect our business, financial condition, and operating results.

Our business, financial condition, and operating results are sensitiveaffected toby changes in general economic and political conditions, including interest rates, consumer credit conditions, consumer debt levels, consumer confidence, unemployment rates, economic growth, tariffs and trade restrictions, fluctuations in global currencies, immigration policies, energy costs, rates of inflation (or concerns about deflation), supply chain disruptions, impacts of current geopolitical conflict or instability, such as the Ukraine-Russia and Israel-Hamas wars and any further escalations thereof, and other macroeconomic factors.

The wirelesstelecommunications industry, broadly, is dependent on population growth, asincluding growth in the immigrant population. As a result, we expect the wirelesstelecommunications industry’s customer growth rate to be moderate in comparison with historical growth rates, leading to ongoing competition for customers. In addition, the Government Commitments place certain limitations on our ability to increase prices, which limits our ability to pass along growing costs to customers. Rising prices for goods, services, and labor due to inflation, including inflation resulting from higher tariffs, restrictions, and other economic disincentives to trade, could adversely impact our margins and/or growth.

Weak economic and credit conditions may also adversely impactaffect our suppliers, dealers, wholesale partners or MVNOs, and enterprise and government customers, some of which may file for bankruptcy, or may experience cash flow or liquidity problems, or may be unable to obtain or refinance credit such that they may no longer be able to operate. Any of these could adversely impact our ability to distribute, market, or sell our products and services.

If we do not successfully deliver new products and services, we may not realize our intended growth targets or generate the expected returns from our business, adversely affecting our financial condition,condition and operating results.

We continue to expand our offerings beyond traditional wireless services to include High Speed Internetbroadband (includingfixed fiber broadband), advertising technologywireless and services, andfiber), specialized network solutions, such as network slicing for first responders (“T-Priority”) and 5G advanced network solutions (“ANS”) for enterprises.enterprises, advertising technology and services, and financial products, such as the T-Mobile Visa credit card introduced in November 2025. These new ventures require significant capital, expertise, and operational support, and their success depends on factors we cannot fully control or predict. Increased competition, technical challenges, security concerns, operational complexities, or shifting regulatory landscapes could delay product rollouts, inflate costs, or limit adoption rates. Additionally, entering new markets or lines of business may expose us to unfamiliar regulatory requirements, compliance challenges, or damagerisks to existing customer relationships. Customer demand for new products and services is difficult to predict, and adoption may be slower than anticipated or may not occur at all. Should these new products and services fail to gain traction, achieve sufficient customer adoption, generate expected financial returns, or deliver value to customers, we could incur substantial expenses without offsetting revenue gains, adversely affecting our business, financial condition, operating results and operatingcompetitive results.position.

We have a diversebroad set of suppliers to help us develop, maintain, and troubleshoot products and services such as wireless and wirelinefiber network components, software development services, and billing and customer service support. However, in certain areas such as,as billing services, voice, and data communications transport services, wireless or wirelinefiber network infrastructure equipment, handsets, other devices, back-office processesprocesses, and payment processing, there are a limited number of suppliers whothat can provide adequate support for us,support, which decreases our flexibility to switch to alternative third parties. Unexpected termination of our arrangement with any of these supplierssuppliers, or difficulties in renewing our commercial arrangements with themthem, could have a material and adverse effect on our business operations.

Our suppliers and third-party technology partners are also subject to their own risks, including, but not limited to, cybersecurity, economic, financial and credit conditions, labor force disruptions, geopolitical tensions, disruptions in global supply chain and the risks ofchain, natural catastrophic eventsevents, (such as earthquakes, floods, hurricanes, storms, heatwaves and fires),fires, energy shortages, power outages, equipment failures, terrorist attacks or other hostile acts, and public health crises, such as the COVID-19 pandemic,pandemic. whichThese events may result in performance below the levels required by their contracts.contracts Ouror cause them to suspend, limit, or cease their operations, or terminate or reduce their relationship with us. We could experience severe business coulddisruptions beand severelydelays disruptedin technology initiatives if critical suppliers or service providers fail to comply with their contracts orcontracts, if we experience delays or service degradation during any transition to a new outsourcing provider or other suppliersupplier, 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.

Further, some of our suppliers may provide services from outside of the United States, which carries additional regulatory and legal obligations. We rely on 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 policies and standards, including our Supplier Code of Conduct and our third-party risk management practices. The failure of our suppliers to comply with our expectations and policies could expose us to additional legal and litigation risks and lead to unexpected contract terminations.

The current sociopolitical environment is characterized by deep complexity, volatility, and polarization on various social and political issues. The increasing intersection of technology and politics has led to rapid and unpredictable shifts in public sentiment. Social media and digital platforms have amplified the voices of various stakeholders, creating the potential for swift change in public opinion and stronger reactions to corporate actions. As a company that sells products and services across the nation to millions of customers, these dynamics increase the risk of potential reputational damage, boycotts, and shifts in consumer behavior that could adversely affect our brand, salessales, and profitability. Our ability to respond effectively, sensitively, and authentically to the expectations and concerns of our customers, employees, and other stakeholders is key to mitigating these risks. If we are unable to manage these challenges effectively, there may be adverse impacts toon our business, reputation, financial condition, and operating results.

Additionally, we are subject to emerging and evolving regulatory requirements and frameworks regarding environmental, social and governance matters, including potential new or revised disclosure rules proposed by the SEC and recently enacted or proposed legislation in jurisdictions such as California. The ultimate scope of these regulations may change as they are finalized, and they may not be uniform across jurisdictions. Meeting these obligations may require significant investments of time, capital, and personnel.

Our substantial level of indebtedness could adversely affect our business flexibility and ability to service our debt,debt and could increase our borrowing costs.

We have, and we expect that we will continue to have, a substantial amount of debt. Our substantial level of indebtedness could have the effect of, among other things, reducing our flexibility in responding to changing business, economic, marketmarket, and industry conditions and increasing the amount of cash required to service our debt. In addition, this level of indebtedness may also reduce funds available for capital expenditures, any Board-approved share repurchases, dividendsdividends, or other activities. Those impacts may put us at a competitive disadvantage relative to other companies with lower debt levels. Further, we may incur substantial additional indebtedness in the future, subject to the restrictions contained in our debt instruments, if any, which could increase the risks associated with our capital structure.

Our ability to service our substantial debt obligations will depend on future performance, which will be affected by business, economic, marketmarket, and industry conditions and other factors. There is no guarantee that we will be able to generate sufficient cash flow to service our debt obligations when due. If we are unable to meet such obligations or fail to comply with the financial and other restrictive covenants contained in the agreements governing such debt obligations, we may be required to refinance all or part of our debt, sell important strategic assets at unfavorable pricesprices, or make additional borrowings. We may not be able to, at any given time, refinance our debt, sell assets, or make additional borrowings on commercially reasonable terms or at all, which could have a material adverse effect on our business, financial condition, and operating results.

Instability in the global financial markets, inflation, policies of various governmental and regulatory agencies, including changes in monetary policy and interest rates, and other general economic conditions could lead to volatility in the credit and equity markets. This volatility could limit our access to the capital markets, leading to higher borrowing costs or, in some cases, thean inability to obtain financing on terms that are acceptable to us or at all. Further, deterioration in our operating performance may lead to a decrease in our credit ratings, which could also impact our ability to access the debt capital markets at rates favorable or acceptable to us.

UScellular Merger-Related Costs

Merger-related costs associated with ourthe MergerUScellular withAcquisition Sprintto generallydate include:

Sprint Merger-related costs have been excluded from our calculations of Adjusted EBITDA and Core Adjusted EBITDA, which are non-GAAP financial measures, as we do not consider these costs to be reflective of our ongoing operating performance. See “Adjusted EBITDA and Core Adjusted EBITDA” in the “Performance Measures” section of this MD&A. Net cash payments for Sprint Merger-related costs, including payments related to our restructuring plan, are included in Net cash provided by operating activities on our Consolidated Statements of Cash Flows and our calculation of Adjusted Free Cash Flow.

During the year ended December 31, 2024, we recognized a gain for the $100 million extension fee previously paid by DISH associated with the DISH License Purchase Agreement (as defined in Note 7 – Goodwill, Spectrum License Transactions and Other Intangible Assets of the Notes to the Consolidated Financial Statements) as a reduction to Selling, general and administrative expenses on our Consolidated Statements of Comprehensive Income. The gain was presented as a reduction in Merger-related costs and excluded from our calculations of Adjusted EBITDA and Core Adjusted EBITDA. See Note 7 – Goodwill, Spectrum License Transactions and Other Intangible Assets of the Notes to the Consolidated Financial Statements for more information.

As of June 30, 2024, we have incurred substantially all restructuring and integration costs associated with the Sprint Merger and, accordingly, no longer separately disclose Sprint Merger-related costs. The cash payments for the Sprint Merger-related costs incurred extend beyond 2024.2025 Cash payments extending beyond 2024and primarily relate to operating and financing leases for which we have recognized accelerated lease expense. See Note 19 – Restructuring Costs of the Notes to the Consolidated Financial Statements for more information.

Sprint Merger-related costs are presented below:

Our MD&A is provided as a supplement to, and should be read together with, our unaudited condensed consolidated financial statements as of and for the three and six months ended MarchJune 31,30, 2026, included in Part I, Item 1 of this Form 10-Q, and audited consolidated financial statements, included in Part II, Item 8 of our Annual Report on Form 10-K for the year ended December 31, 2025. Except as expressly stated, the financial condition and results of operations discussed throughout our MD&A are those of T-Mobile US, Inc. and its consolidated subsidiaries.

On August 1, 2025 (the “UScellular Acquisition Date”), we completed the acquisition (the “UScellular Acquisition”) of substantially all of United States Cellular Corporation’s (“UScellular”) wireless operations and select spectrum assets and the acquisition of substantially all of the wireless operations assets of each of Farmers Cellular Telephone Company, Inc., Iowa RSA No. 9 Limited Partnership,Partnership and Iowa RSA No. 12 Limited Partnership (collectively, the “UScellular Wireless Business”). In exchange, on the UScellular Acquisition Date, we transferred cash of $2.8 billion. Additionally, the closing of the UScellular Acquisition obligated us to execute exchange offers, which were launched on May 23, 2025 (the “Exchange Offers”). On August 5, 2025, we executed the Exchange Offers of certain senior notes of UScellular with an aggregate outstanding principal balance of $1.7 billion for T-Mobile notes.

As a result of our UScellular Acquisition restructuring and integration activities, we expect to realize cost efficiencies by eliminating redundancies within our combined network as well as other business processes and operations. Upon completion of these activities, we expect to achieve total annual run rate cost synergies of $1.2 billion, consisting of $950 million in operating expenses and $250 million in capital expenditures. We currently expect total costs to achieve, excluding accelerated depreciation, to be approximately $2.6 billion, currently expected to be comprisedcomposed of $1.5 billion of UScellular merger-related costs recognized within operating expenses and $1.1 billion of capital expenditures.

OurSubstantially remainingall costs and associated payments for our UScellular Acquisition restructuring and integration activities associated with the UScellular Acquisition are expected to occur over the next two years, with substantially all costsbe incurred and associated cash payments made by the end of fiscal year 2027. We are evaluating additional restructuring initiatives associated with the UScellular Acquisition, which are dependent on consultations and negotiations with certain counterparties and the expected impact on our business operations, which could affect the amount or timing of the costs and related payments.

On May 1, 2024 (the “Ka’ena Acquisition Date”), we completed the merger with Ka’ena Corporation and its subsidiaries, including, among others, Mint Mobile LLC (collectively, “Ka’ena”), and as a result, Ka’ena became a wholly owned subsidiary of T-Mobile (the “Ka’ena Acquisition”). The total purchase price consists of an upfront payment on the Ka’ena Acquisition Date and an earnout payable in the thirdsecond quarterhalf of 2026. Based on the adjusted amount paid upfront, an additional $420 million in future cash and T-Mobile common stock is payable in satisfaction of the earnout.

Fiber Joint Ventures

On July 24, 2025, we completed the joint acquisition of Metronet Holdings, LLC and certain of its affiliates (collectively, “Metronet”), a fiber-to-the-home platform. During the three months ended September 30, 2025, we invested $4.6 billion to acquire a 50% equity interest in the joint venture and residential fiber customers. Following the joint acquisition, Metronet became a wholesale services provider, and its residential fiber retail operations and customers transitioned to us. We do not anticipate making further capital contributions under the existing business plan.

Subsequent to March 31, 2026, onOn April 24, 2026, we entered into a definitive agreement with an affiliate of Wren House Infrastructure Management Limited (“Wren House”) to establish a joint venture that will acquire i3 Broadband, one of Wren House’s existing fiber portfolio companies. The transaction with Wren House is expected to close in the second half of 2026, subject to customary closing conditions and regulatory approvals, at which time we expect to invest approximately $700 million to acquire a 50% equity interest in the joint venture and substantially all existing residential fiber customers. Additionally, on April 25, 2026, we entered into definitive agreements with affiliates of Oak Hill Capital Management, LLC (“Oak Hill”) to establish a joint venture that will acquire and combine GoNetspeed and Greenlight Networks, two of Oak Hill’s existing fiber portfolio companies. The transaction with Oak Hill is expected to close in the first half of 2027, subject to customary closing conditions and regulatory approvals, at which time we expect to invest approximately $2.0 billion to acquire a 50% equity interest in the joint venture and substantially all existing residential fiber customers. We expect to account for these joint ventures under the equity method of accounting and recognize service revenues for the acquired fiber customers and wholesale costs paid to the joint venture for network access within Postpaid revenues and Cost of services, respectively, on our Condensed Consolidated Statements of Comprehensive Income.

Our Network Restructuring Initiative is expected to be completed prior to the end of 2027, with a majority of costs incurred by the end of 2026. We currently expect to incur between $500 million and $800 million of total costs associated with the Network Restructuring Initiative. We are evaluating additional restructuring activities associated with the Network Restructuring Initiative, which are dependent on consultations and negotiations with certain counterparties and the expected impact on our business operations, which could affect the amount or timing of the restructuring costs and related payments.

In the fourth quarter of 2025, we began implementing a restructuring initiative to streamline operations by centralizing leaders and teams, reducing organizational layers,layers and eliminating duplicative roles (the “2025-2026 Workforce Transformation”). We intend to reinvest the expected cost savings from the 2025-2026 Workforce Transformation into the business, including into our digital initiatives.

During the threesix months ended MarchJune 31,30, 2026, we recorded a pre-tax charge of $141 million related to the 2025-2026 Workforce Transformation, which isare included in Cost of services and Selling, general and administrative expenses on our Condensed Consolidated Statements of Comprehensive Income. We have incurred substantially all of the costs associated with our 2025-2026 Workforce Transformation initiative and expect substantially all remaining associated employee separations and related cash outflows to occur inthroughout 2026.

The following discussion and analysis is for the three and six months ended MarchJune 31,30, 2026, compared to the same periodperiods in 2025, unless otherwise stated.

Total revenues increased $2.2$1.7 billion, or 11%.8%, for the three months ended and increased $3.9 billion, or 9%, for the six months ended June 30, 2026. The components of these changes are discussed below.

Postpaid revenues increased $2.0$1.8 billion, or 15%,13%, primarilyfor from:the three months ended and increased $3.8 billion, or 14%, for the six months ended June 30, 2026.

•LowerPrepaid revenues decreased $170 million, or 6%, for the three months ended and decreased $296 million, or 6%, for the six months ended June 30, 2026, primarily from lower average revenue per customer, primarily from dilution from promotional activity and rate plan mix; partially offset bymix.

Equipment revenues increased $292$85 million, or 8%,2%, primarilyfor from:the three months ended and increased $377 million, or 5%, for the six months ended June 30, 2026.

•An increase of $191 million in device sales revenue, primarily from higherHigher average revenue per device sold, net of promotions, primarily driven by an increase in the high-end phone mix; andpartially offset by

•An increase of $224 million in liquidationdevice sales revenue, primarily due to afrom higher numberaverage revenue per device sold, net of liquidatedpromotions, devicesprimarily anddriven by an increase in the high-end phone mix.mix; and

Total operating expenses increased $2.5$1.4 billion, or 16%.9%, for the three months ended and increased $3.9 billion, or 12%, for the six months ended June 30, 2026. The components of this change are discussed below.

Cost of services, exclusive of depreciation and amortization, increased $737$261 million, or 28%10%, primarilyfor from:the three months ended and increased $998 million, or 19%, for the six months ended June 30, 2026.

Cost of equipment sales, exclusive of depreciation and amortization, increased $690$396 million, or 14%,8%, primarilyfor from:the three months ended and increased $1.1 billion, or 11%, for the six months ended June 30, 2026.

•An increase of $559 million in device cost of equipment sales, primarily from higherHigher average cost per device sold, primarily driven by an increase in the high-end phone mix; andpartially offset by

•An increase of $917 million in liquidationdevice costs,cost of equipment sales, primarily due to afrom higher numberaverage ofcost liquidatedper devicesdevice andsold, primarily driven by an increase in the high-end phone mix.mix; and

Selling, general and administrative expenses increased $478$437 million, or 9%,8%, primarilyfor from:the three months ended and increased $915 million, or 8%, for the six months ended June 30, 2026.