T-MOBILE US 1 GROUP STRATEGY Germany Systems Solutions Technology & Innovation T-Mobile US Europe Group Development Finance

LEGAL DISCLAIMER Important Additional Information In connection with the proposed transaction, T-Mobile US, Inc. (“T-Mobile”) will file a registration statement on Form S-4, which will contain a joint consent solicitation statement of T-Mobile and Sprint Corporation (“Sprint”), that also constitutes a prospectus of T-Mobile (the “joint consent solicitation statement/prospectus”), and each party will file other documents regarding the proposed transaction with the U.S. Securities and Exchange Commission (the “SEC”). INVESTORS AND SECURITY HOLDERS ARE URGED TO READ THE JOINT CONSENT SOLICITATION STATEMENT/PROSPECTUS AND OTHER RELEVANT DOCUMENTS FILED WITH THE SEC WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION. When final, a definitive copy of the joint consent solicitation statement/prospectus will be sent to T-Mobile and Sprint stockholders. Investors and security holders will be able to obtain the registration statement and the joint consent solicitation statement/prospectus free of charge from the SEC’s website or from T-Mobile or Sprint. The documents filed by T-Mobile with the SEC may be obtained free of charge at T-Mobile’s website, at www.t-mobile.com, or at the SEC’s website, at www.sec.gov. These documents may also be obtained free of charge from T-Mobile by requesting them by mail at T-Mobile US, Inc., Investor Relations, 1 Park Avenue, 14th Floor, New York, NY 10016, or by telephone at 212-358-3210. The documents filed by Sprint with the SEC may be obtained free of charge at Sprint’s website, at www.sprint.com, or at the SEC’s website, at www.sec.gov. These documents may also be obtained free of charge from Sprint by requesting them by mail at Sprint Corporation, Shareholder Relations, 6200 Sprint Parkway, Mailstop KSOPHF0302-3B679, Overland Park, Kansas 66251, or by telephone at 913-794-1091. Participants in the Solicitation T-Mobile and Sprint and their respective directors and executive officers and other members of management and employees may be deemed to be participants in the solicitation of consents in respect of the proposed transaction. Information about T-Mobile’s directors and executive officers is available in T-Mobile’s proxy statement dated April 26, 2018, for its 2018 Annual Meeting of Stockholders. Information about Sprint’s directors and executive officers is available in Sprint’s proxy statement dated June 19, 2017, for its 2017 Annual Meeting of Stockholders, and in Sprint’s subsequent reports on Form 8-K filed with the SEC on January 4, 2018 and January 17, 2018. Other information regarding the participants in the consent solicitation and a description of their direct and indirect interests, by security holdings or otherwise, will be contained in the joint consent solicitation statement/prospectus and other relevant materials to be filed with the SEC regarding the acquisition when they become available. Investors should read the joint consent solicitation statement/prospectus carefully when it becomes available before making any voting or investment decisions. You may obtain free copies of these documents from T-Mobile or Sprint as indicated above. No Offer or Solicitation This communication shall not constitute an offer to sell or the solicitation of an offer to buy any securities, nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. No offering of securities shall be made except by means of a prospectus meeting th e requirements of Section 10 of the U.S. Securities Act of 1933, as amended. Cautionary Statement Regarding Forward-Looking Statements This communication contains certain forward-looking statements concerning T-Mobile, Sprint and the proposed transaction between T-Mobile and Sprint. All statements other than statements of fact, including information concerning future results, are forward-looking statements. These forward-looking statements are generally identified by the words “anticipate,” “believe,” “estimate,” “expect,” “intend,” “may,” “could” or similar expressions. Such forward-looking statements include, but are not limited to, statements about the benefits of the proposed transaction, including anticipated future financial and operating results, synergies, accretion and growth rates, T-Mobile’s, Sprint’s and the combined company’s plans, objectives, expectations and intentions, and the expected timing of completion of the proposed transaction. There are several factors which could cause actual plans and results to differ materially from those expressed or implied in forward-looking statements. Such factors include, but are not limited to, the failure to obtain, or delays in obtaining, required regulatory approvals, and the risk that such approvals may result in the imposition of conditions that could adversely affect the combined company or the expected benefits of the proposed transaction, or the failure to satisfy any of the other conditions to the proposed transaction on a timely basis or at all; the occurrence of events that may give rise to a right of one or both of the parties to terminate the business combination agreement; adverse effects on the market price of T-Mobile’s or Sprint’s common stock and on T-Mobile’s or Sprint’s operating results because of a failure to complete the proposed transaction in the anticipated timeframe or at all; inability to obtain the financing contemplated to be obtained in connection with the proposed transaction on the expected terms or timing or at all; the ability of T-Mobile, Sprint and the combined company to make payments on debt or to repay existing or future indebtedness when due or to comply with the covenants contained therein; adverse changes in the ratings of T-Mobile’s or Sprint’s debt securities or adverse conditions in the credit markets; negative effects of the announcement, pendency or consummation of the transaction on the market price of T-Mobile’s or Sprint’s common stock and on T-Mobile’s or Sprint’s operating results, including as a result of changes in key customer, supplier, employee or other business relationships; significant transaction costs, including financing costs, and unknown liabilities; failure to realize the expected benefits and synergies of the proposed transaction in the expected timeframes or at all; costs or difficulties related to the integration of Sprint’s network and operations into T-Mobile; the risk of litigation or regulatory actions; the inability of T-Mobile, Sprint or the combined company to retain and hire key personnel; the risk that certain contractual restrictions contained in the business combination agreement during the pendency of the proposed transaction could adversely affect T-Mobile’s or Sprint’s ability to pursue business opportunities or strategic transactions; effects of changes in the regulatory environment in which T-Mobile and Sprint operate; changes in global, political, economic, business, competitive and market conditions; changes in tax and other laws and regulations; and other risks and uncertainties detailed in T-Mobile’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017 and in its subsequent reports on Form 10-Q, including in the sections thereof captioned “Risk Factors” and “Cautionary Statement Regarding Forward-Looking Statements,” as well as in its subsequent reports on Form 8-K, all of which are filed with the SEC and available at www.sec.gov and www.t-mobile.com. Forward-looking statements are based on current expectations and assumptions, which are subject to risks and uncertainties that may cause actual results to differ materially from those expressed in or implied by such forward-looking statements. Given these risks and uncertainties, persons reading this communication are cautioned not to place undue reliance on such for ward-looking statements. T-Mobile assumes no obligation to update or revise the information contained in this communication (whether as a result of new information, future events or otherwise), except as required by applicable law. Non-GAAP In addition to financial information prepared in accordance with U.S. GAAP, this presentation also contains adjusted financial measures that we believe provide investors and management with supplemental information relating to operating performance and trends that facilitate comparisons between periods and with respect to projected information. These adjusted financial measures are non-GAAP and should be considered in addition to, but not as a substitute for, the information prepared in accordance with U.S. GAAP. Further information relevant to the interpretation of adjusted financial measures, and reconciliations of these adjusted financial measures to the most comparable GAAP measures, may be found on T-Mobile's website at http://investor.t-mobile.com in the "Quarterly Results" section

SUPERCHARGING THE UN-CARRIER 17 GROUP STRATEGY GERMANY SYSTEMS SOLUTIONS TECHNOLOGY &INNOVATION T·MOBILE US EUROPE GROUP DEVELOPMENT FINANCE

CREATING IN THE 5G ERA ROBUST COMPETITION UNLOCKING ECONOMIC VALUE UNPRECEDENTED CAPACITY, SPEED AND LATENCY TO DRIVE REVOLUTIONARY CONSUMER EXPERIENCE UNLOCKING SIGNIFICANT ECONOMIC VALUE NETWORK CAPABILITIES AND CAPACITY WILL LEAD TO BETTER SERVICE AND LOWER PRICES CREATING NEW JOBS DAY ONE WITH INVESTMENT TO EXPAND CUSTOMER SERVICE, RETAIL FOOTPRINT AND 5G BUILDOUT CONTINUATION OF PROVEN PRO-CONSUMER STRATEGY THAT IS FUNDAMENTALLY BUILT AROUND MORE VALUE AND HIGHER CONSUMER SATISFACTION ACCELERATE U.S. POSITION IN 5G AS THE ONLY COMPANY ABLE TO QUICKLY DEPLOY A BROAD AND DEEP NATIONWIDE 5G NETWORK DRIVING RAPID INVESTMENT NATIONWIDE IN 5G, ENSURING AMERICAN LEADERSHIP IN 5G ECO-SYSTEM PROACTIVELY CREATE NEW COMPETITION AND DISRUPTION IN ADJACENT MARKETS FORCING CONVERGED INDUSTRY LEADERS TO INVEST MORE AND FASTER USE EARLY LEADERSHIP IN 5G TO CAPTURE WAVE OF INNOVATION AND DISRUPTION, BENEFITING CUSTOMERS AND THE NATION’S ECONOMY BRING REAL MOBILE BROADBAND COMPETITION TO RURAL AMERICANS FOR THE FIRST TIME AND NEW COMPETITION FOR BUSINESSES OF ALL SIZES ACCELERATING THE GROWTH OF MILLIONS1 OF U.S. JOBS AND SUBSTANTIAL ECONOMIC VALUE 1 Based on CTIA estimates from “The Global Race to 5G” April 2018. 18 GROUP STRATEGY Germany Systems Solutions Technology & Innovation T-Mobile US Europe Group Development Finance JOB CREATOR FROM DAY ONE SUPERCHARGE UN-CARRIER STRATEGY AT PIVOTAL TIME UNPRECEDENTED NATIONWIDE 5G NETWORK

NEW T-MOBILE WILL DELIVER SIGNIFICANT SYNERGIES RUN-RATE COST TO ACHIEVE ($BN)1 NPV OF SYNERGIES ($BN) (Net of Costs to Achieve) INTEGRATION YEARS SYNERGIES ($BN, PRE-TAX) SITE DECOMMISSIONING, COST TO DECOMMISSION, NETWORK INTEGRATION STORE CONSOLIDATION, INCREASED LEASE & LABOR EXPENSE, STORE REFRESH IT & BILLING & FIXED G&A TOTAL Note: All numbers are approximations and reflect management estimates as of date of presentation. 1 NPV of Synergies net of Costs to Achieve, calculated assuming a discount rate of 8.0% on unlevered free cash flow. Numbers may not add due to rounding. 2 Net of avoided Capital Expenditures. 19 GROUP STRATEGY Germany Systems Solutions Technology & Innovation T-Mobile US Europe Group Development Finance ~ $43+ ~ $15 ~ $6+ BACK OFFICE 3-4 ~ $6 ~ $1+ ~ $4 SALES, SERVICE & MARKETING COST, ADVERTISING, CUSTOMER CARE, EQUIPMENT REVENUE & LOGISTICS 3-4 ~ $11 ~ $1+ ~ $1 NETWORK COSTS & CAPEX SAVINGS 3 ~ $26 ~ $4+ ~ $10 2

POISED FOR SIGNIFICANT MARGIN EXPANSION 3-4 Year Targets Longer-term Targets 2018 Pro Forma Margins 2018 Pro Forma 2-4% CAGR $81-86bn 3-5% CAGR $95-100bn Total Revenue $75-76bn Wireless Service Revenue 2-4% CAGR $59-61bn 2-4% CAGR $67-70bn $53-57bn Adjusted EBITDA1,2 $22-23bn 40-42% 45-47% margin 54-57% margin Capital Expenditures3 $10-11bn 18-19% 15-20% of svc rev 13-15% of svc rev Adjusted EBITDA less Capital Expenditures1,4 $11-12bn 20%-21% 26-30% margin 42-45% margin Note: Service Revenue and Adjusted EBITDA figures do not include the impacts of new revenue standard. numbers are approximations and reflect management estimates of the date of presentation All 2Adjusted EBITDA margins calculated based on Service Revenue. 3Capital Expenditures margins calculated based on Service Revenue. 4 Adjusted EBITDA less Capital Expenditures calculated based on Service Revenue. 1Adjusted EBITDA based on T-Mobile’s as-reported definition which is unburdened for stock-based compensation. 20 GROUP STRATEGY Germany Systems Solutions Technology & Innovation T-Mobile US Europe Group Development Finance

TTHOECRFEIRATSETTBHRE OFIARDSTANNADTIODNEWEIPDEN5AGTNIOETNWWOIRDKE 5G NETWORK Available spectrum for 5G New T-Mobile is the ONLY company capable of delivering NATIONWIDE 5G in critical early stage of innovation Mid-band assets to create a broad AND deep what either company could do alone to COMPANY CAPABLE OF DELIVERINNGeBwRTO-AMDoAbNilDe DEEP IN CRITICAL EARLY STAGE OF INNOVATION Proven leadership and plan to rapidly deployed nationwide LTE twice as fast AT&T Nationwide 21 GROUP STRATEGY Germany Systems Solutions Technology & Innovation T-Mobile US Europe Group Development Finance Unmatched combination of spectrum network Enhanced financial position above mmW Low-band invest iNn tEhWe roTl-lMouOt oBf I5LGE IS THE ONLY NATIONWIDE 5G rollout advancements – T-Mobile as Verizon and three times as fast as mmWDense Urban Mid-bandMetro Low-band NTeEHwWETT--MNoOEbBWiIlLeE:TT-hMe OFirBstILBrEoaHdAanSdTDHeeEp BNaRtiEonAwDidTeH5G&NDetEwoPrTk H

)(ACITY SPEED & 22 450 CAPACITY INCREASE {EXABYTES) SPEED INCREASE (MBPS) 3 32.1 23.8 ··Mobile·+Sprint). 1Q18 OFFERED CAPACITY (IN EXABYTES PER MONTH) ··Mobile· ··Mobile·Sprint). 1Q18 DOWNLOADSPEED ··Mobile· NEW NEW PROJECTED-2024 OFFERED CAPACITY (IN EXABYTES PER MONTH) PROJECTED-2024 DOWNLOAD SPEED 22 GROUP STRATEGY GERMANY SYSTEMS SOLUTIONS TECHNOLOGY & INNOVATION T-MOBILE US EUROPE GROUP DEVELOPMENT FINANCE

POTENTIAL 23 T-MOBILE US GROUP STRATEGY GERMANY SYSTEMS SOLUTIONS TECHNOLOGY & INNOVATION EUROPE GROUP DEVELOPMENT FINANCE

PROVEN OPERATIONAL PLAN FOR SUCCESS Anchor on T-Mobile Network Migrate customers Fast and low risk delivery of synergies customer experience while protecting Migrate Sprint customers to T-Mobile network within 3 years without degrading experience on Sprint’s network On Day One, 20 million Sprint customers already have compatible handsets with T-Mobile’s network Aggressively migrate CDMA voice to VoLTE Billing and back office system migrations to occur over time minimizing disruption to distribution, care, and operations Use T-Mobile as the anchor network and increase network density and coverage with selected Sprint “keep” sites Deploy 2.5 GHz spectrum on T-Mobile sites and full T-Mobile spectrum portfolio on Sprint “keep” sites New T-Mobile network of ~85k macro sites and 50k small cells 24 GROUP STRATEGY Germany Systems Solutions Technology & Innovation T-Mobile US Europe Group Development Finance

NEW T-MOBILE WILL DELIVER UNPRECEDENTED NETWORK QUALITY AND CUSTOMER VALUE Rapid industry convergence and fast emerging 5G economy creates ideal timing for unique combination Creates only company with capacity to build the first broad and deep nationwide 5G network Competition will extend U.S. global internet leadership in the 5G era Supercharges pro-consumer Un-carrier strategy Expected to create jobs and unlock economic growth Compelling benefits support rationale for regulatory approval in the era of 5G 25 GROUP STRATEGY Technology Leadership Germany T-Systems Europe/NL TMUS Finance

Exceeded or met aggressive goals set at Capital Markets Day 2012 & 2015 Industry leading momentum set to continue with strong organic plan Incredible LTE Network transitioning to 5G using 600 MHz Sprint transaction enables unprecedented network quality & customer value New T-Mobile will create value for consumers investors & 26 GROUP STRATEGY Technology Leadership Germany T-Systems Europe/NL TMUS Finance T-Mobile US, Inc. CMD 2018 Summary