TABLE OF CONTENTS

T-Mobile is committed to good corporate governance

Our corporate governance practices and policies promote the long-term interests of our stockholders, strengthen the accountability of our Board and management and help build public trust.

Our Board has established a boardroom dynamic that encourages meaningful and robust discussions based on each director’s unique and

diverse background, resulting in informed decision-making that seeks to maximize stockholder value and promotes stockholder interests. Directors exercise thorough oversight of decisions regarding the Company’s strategy and outlook. The Board regularly reviews developments in corporate governance and updates its practices and governance materials as it deems necessary and appropriate.

Governance Framework and Code of Business Conduct

Our Board has adopted Corporate Governance Guidelines, which, together with our certificate of incorporation, our bylaws and the Stockholder’s Agreement with Deutsche Telekom, provide a framework for the effective governance of the Company.

The Board also adopted our Code of Business Conduct, which establishes the standards of ethical conduct applicable to our directors, officers and employees. In addition, we have a Code of Ethics for Senior Financial Officers. In the event of a waiver by the Board of any Code of Business Conduct or Code of Ethics for Senior Financial Officers provisions applicable to directors or executive officers, we will promptly disclose the Board’s actions on our website.

Our Board and Director Independence

Our Board consists of 12 directors, two of whom are currently employed by the Company. Pursuant to our certificate of incorporation and the Stockholder’s Agreement, Deutsche Telekom has certain rights to designate director nominees and to have such designees serve on the committees of the Board. See “Transactions With Related Persons and Approval — Transactions with Deutsche Telekom — Stockholder’s Agreement” for more information.

We Are a Controlled Company with Certain Exemptions

Since Deutsche Telekom beneficially owns a majority of our outstanding stock (approximately 63% as of March 31, 2018), we are deemed a “controlled company” under the NASDAQ Stock Market LLC (“NASDAQ”) rules. These rules exempt “controlled companies,” like us, from certain corporate governance requirements, including: (a) that a majority of our Board be independent, (b) that our Nominating and Corporate Governance Committee be composed entirely of independent directors and (c) that our Compensation Committee be composed entirely of independent directors. In addition, we rely on the exemption for controlled companies from NASDAQ rules adopted pursuant to the Dodd-Frank Wall Street Reform and Consumer Protection Act (the “Dodd-Frank Act”) that relate to compensation committee member independence and compensation committee consultants.

Director Independence

On an annual basis, our Board evaluates the independence of each director, including nominees for election to the Board, in accordance with NASDAQ rules and our Corporate Governance Guidelines. For certain types of relationships, NASDAQ rules require us to consider a director’s relationship with the Company, and also with any parent or subsidiary in a consolidated group with the Company, which includes Deutsche Telekom and its affiliates. Each of the following directors or director nominees is an “independent director” under NASDAQ rules and our Corporate Governance Guidelines:

Board Leadership

Our Chairman and Our Chief Executive Officer Roles Are Separated

We believe that separating the roles of Chief Executive Officer and Chairman of the Board is appropriate for the Company and in the best interests of the Company and its stockholders at this time. Timotheus Höttges, Deutsche Telekom’s Chief Executive Officer, is the Chairman of the Board. Key responsibilities of our Chairman include:

The separation of the offices allows Mr. Höttges to focus on management of Board matters and allows our Chief Executive Officer to focus on managing our business. Additionally, we believe the separation of the roles ensures the objectivity of the Board in its management oversight role, specifically with respect to reviewing and assessing our Chief Executive Officer’s performance. The Board believes that its role in risk oversight did not impact the leadership structure chosen by the Board.

We Have a Lead Independent Director

Our Board has also chosen to also appoint a lead independent director. Teresa A. Taylor is our current lead independent director. Key responsibilities of our lead independent director include:

Board Meetings and Director Attendance

Our Board meets regularly throughout the year. Committees typically meet the day prior to the Board meeting and depending on the schedule of the Board meeting, the Audit Committee holds additional meetings in connection with quarterly earnings. Directors are expected to attend all meetings of the Board and each committee on which they serve, as well as the Annual Meeting of Stockholders. At each regularly-scheduled Board meeting (or more frequently if necessary), time is set aside for executive sessions where outside (non-management) directors meet without management present. In addition, our Corporate Governance Guidelines require the independent directors to meet at least twice each year in executive session, with the lead independent director presiding at such executive session.

The Compensation Committee Has Engaged an Independent Compensation Consultant

The Compensation Committee has retained Mercer (a wholly-owned subsidiary of Marsh & McLennan Companies, Inc.), a well-recognized employee benefits and compensation consulting firm, as its independent compensation consultant. Mercer assists the Committee in its evaluation of the compensation and benefits provided to the Chief Executive Officer and the other executive officers. Mercer generally attends the Committee meetings at which executive officer compensation is discussed and provides information, research and analysis pertaining to executive compensation as requested by the Compensation Committee. Mercer also updates the Compensation Committee on market trends.

During 2017, Mercer provided executive compensation services to the Company. The aggregate fees for such services were approximately $215,000. In addition, Mercer provided services to the Company for investment and benefits consulting and retirement plan consulting. The aggregate fees for such services were approximately $140,000.

Compensation Committee Interlocks and Insider Participation

During 2017, Ms. Taylor and Messrs. Barnes, Dannenfeldt, Guffey and Kübler served as members of our Compensation Committee. No member of the Compensation Committee who served during 2017 was an officer or employee of the Company or any of its subsidiaries during the year, was formerly a Company officer or had any relationship otherwise requiring disclosure as a compensation committee interlock.

Management of the Company, including the Chief Executive Officer and other executive officers, is primarily responsible for managing the risks associated with the business, operations, and financial and disclosure controls. Management conducts a quarterly enterprise-wide risk assessment and considers financial, strategic, IT, technology, operational, compliance, legal/regulatory, and reputational risks to the Company. The results of these assessments are considered in connection with the operational, financial, and business activities of the Company.

Management Has Established an Enterprise Risk and Compliance Committee and an Information Security and Privacy Council

The Enterprise Risk and Compliance Committee oversees activities in the areas of risk management and compliance as a means of bringing risk issues to the attention of senior management. Responsibilities for risk management and compliance are distributed throughout various functional areas of the business, and the Enterprise Risk and Compliance Committee regularly reviews the Company’s activities in these areas.

The Information Security and Privacy Council, with support from the Senior Vice President, Digital Security, who serves as the Chief Information Security Officer, and the Vice President, Chief Privacy Officer, oversees the strategic governance and prioritization of the Company’s information security and privacy initiatives.

Selective Delegation of Risk Oversight to Committees

While the full Board has overall responsibility for risk oversight, the Board has delegated risk oversight responsibility for certain risks to committees of the Board. On a regular basis, reports of all committee meetings are presented to the Board and the Board periodically conducts deep dives on key enterprise risks.

Audit Committee

The Audit Committee has primary responsibility for overseeing the Company’s various risk assessment and risk management policies. The Audit Committee considers and discusses policies with respect to risk assessment and risk management, including the Company’s major financial risk exposures and the steps management has taken to monitor and control such exposures.

To assist the Audit Committee with its risk assessment function, the Senior Vice President, Internal Audit & Risk Management, who serves as the Chief Audit Executive, and the Vice President, Chief Compliance Officer have direct reporting channels to the Audit Committee, and have regular meetings with the Audit Committee and/or its members. They provide a quarterly enterprise-wide risk assessment and annual fraud and compliance risk assessments to the Audit Committee and update the Audit Committee on significant issues raised by the Enterprise Risk and Compliance Committee.

The Audit Committee reviews all risk assessments, provides feedback to executive management and shares the risk assessments with the Board. The Audit Committee also has other responsibilities with respect to the

Company’s internal audit and SOX Compliance program, as well as other compliance and ethics programs, as more fully set out in its charter.

Compensation Committee

The Compensation Committee has certain responsibilities with respect to the assessment of risk in connection with our compensation programs. The Compensation Committee periodically reviews with management an assessment of whether risks arising from the Company’s compensation policies and practices for all employees are reasonably likely to have a material adverse effect on the Company, as well as the means by which any potential risks may be mitigated, such as through governance and oversight policies. The Company designs the compensation programs to encourage appropriate risk taking while discouraging behavior that may result in unnecessary or excessive risk. In this regard, the following elements have been incorporated in our compensation programs for executive officers:

Executive Committee

The Executive Committee reviews and provides guidance to senior management regarding the Company’s strategy, operating plans and operating performance. The Executive Committee also plays a key role in helping the Board perform its risk oversight function by considering strategic operating goals, opportunities and risks.

Nominating and Corporate Governance Committee

The Nominating and Corporate Governance Committee oversees Board process and corporate governance-related risks.

Non-Employee Director Compensation Program

Our “non-employee directors”—directors who are not employees of the Company or officers or employees of Deutsche Telekom—are eligible to participate in the Company’s non-employee director compensation program, described below. The Compensation Committee periodically reviews the compensation of our non-employee directors. As part of the review, the Compensation Committee engages Mercer to assess our non-employee director compensation program in comparison to our peer group (see “—Executive Compensation—Factors Considered in Determining Executive Compensation—Executive Compensation Peer Group” for more information on our peer group). Based on such assessment, the non-

employee director compensation program is adjusted as appropriate to ensure alignment with market practices.

Key Features of Our Non-Employee Director Compensation Program

The annual award of restricted stock units (“RSUs”) is made immediately after each Annual Meeting of Stockholders. The RSUs vest on the one-year anniversary of the grant date or, for directors not standing for re-election, on the date of the next Annual Meeting of Stockholders, subject to continued service as a non-employee director through the vesting date. In the event of a director’s termination of service prior to vesting, all RSUs are automatically forfeited. The RSUs immediately vest on the date of a change in control of the Company. Annual cash retainers and the annual RSU award are prorated for any person who becomes a non-employee director and/or committee chair, or who otherwise becomes entitled to an additional annual cash retainer as described above, at any time of the year other than the date of the Company’s Annual Meeting of Stockholders. Non-employee directors also receive reimbursement of expenses incurred in connection with their Board service and are eligible to receive up to two handsets per year and up to ten lines of U.S. service pursuant to the Board of Directors Phone Perquisite Program.

Our Directors Are Required to Acquire and Maintain Ownership of Shares of T-Mobile

Under our stock ownership guidelines, each non-employee director is expected to acquire and maintain ownership of shares of common stock equal in value to five times his or her annual cash retainer for Board service measured as of the later of (i) the date we adopted the policy (May 1, 2013) and (ii) the date on which he or she becomes a non-employee director. Each non-employee director is expected to meet the ownership guidelines within the later of (a) five years from the date we adopted the policy and (b) the date on which he or she became a non-employee director, and is expected to retain at least 50% of the net shares of common stock acquired through equity awards until the ownership threshold is met.

Qualifications and Diversity

Subject to Deutsche Telekom’s board designation rights, the Nominating and Corporate Governance Committee is responsible for identifying and evaluating director nominees and recommending to the Board a slate of nominees for election at each Annual Meeting of Stockholders. The Board has adopted director selection guidelines, which the Nominating and Corporate Governance Committee considers in evaluating each director candidate.

Diversity is one of many factors under our director selection guidelines that the Nominating and Corporate Governance Committee considers when

evaluating potential director candidates. However, we do not have a formal policy with respect to diversity on the Board. Our director selection guidelines define diversity broadly to include not just factors such as gender and race, but also factors such as age, ethnic, geographic, cultural and professional diversity.

In connection with its general responsibility to monitor and advise the Board on the size, role, function and composition of the Board, the Nominating and Corporate Governance Committee will periodically consider whether the Board represents the overall mix of skills and characteristics described in the director selection guidelines, including diversity and the other factors described above. Subject to Deutsche Telekom’s board designation rights, the selection process for director candidates is intended to be flexible, and the Nominating and Corporate Governance Committee, in the exercise of its discretion, may deviate from the selection process when particular circumstances warrant a different approach.

Nomination Process

In addition to candidates designated by Deutsche Telekom, the Nominating and Corporate Governance Committee may consider possible director candidates from a number of sources, including those recommended by stockholders, directors, or officers. In addition, the Nominating and Corporate Governance Committee may engage the services of outside consultants and search firms to identify potential director candidates.

A stockholder who wishes to suggest a director candidate for consideration by the Nominating and Corporate Governance Committee should submit the suggestion to the Chair of the Nominating and Corporate Governance Committee, care of our Corporate Secretary, at 12920 SE 38th Street Bellevue, Washington 98006, and include the candidate’s name, biographical data, relationship to the stockholder and other relevant information. The Nominating and Corporate Governance Committee may request additional information about the suggested candidate and the proposing stockholder. Subject to Deutsche Telekom’s board designation rights, the full Board of Directors will approve all final nominations after considering the recommendations of the Nominating and Corporate Governance Committee.

David R. Carey

Mr. Carey serves as our Executive Vice President, Corporate Services and is responsible for leading the Enterprise Program Office, Corporate Communications, Corporate Real Estate, Corporate Responsibility, Corporate Security and a broad range of responsibilities in leading the Office of the CEO. Mr. Carey has also served in the same role with T-Mobile USA, Inc., the wholly-owned subsidiary of the Company (“T-Mobile USA”), since February 2013. Mr. Carey’s career spans 43 years in the telecom and energy services industry. Before joining T-Mobile USA, from October 2011 to February 2013, Mr. Carey served as Chief Executive Officer and Founder of Telescope Advisors, LLC, an advisory firm specializing in telecommunications. From September 1999 to October 2011, Mr. Carey served in various executive positions, including Executive Vice President, Chief Marketing Officer, Head of Global Sales, Strategy and Corporate Development and Chief Ethics Officer at Global Crossing Limited, a telecommunications company. In addition to Global Crossing, his experience includes executive leadership positions at AT&T, LG&E Energy and Frontier Communications. Mr. Carey holds a Master of Science in Management Science from the Massachusetts Institute of Technology, where he was appointed to a Sloan Fellowship, and received his Bachelor of Science degree at Clarkson University. He has also attended executive programs at the Harvard Business School and the Wharton School at the University of Pennsylvania.

J. Braxton Carter

Mr. Carter serves as our Executive Vice President and Chief Financial Officer, and is responsible for leading the financial functions of the Company. Mr. Carter served as MetroPCS Communications, Inc.’s Chief Financial Officer from March 2005 until the consummation of the Business Combination. Mr. Carter also served as MetroPCS Communications Inc.’s Vice Chairman from May 2011 until the consummation of the Business Combination. From February 2001 to March 2005 he was Vice President, Corporate Operations of MetroPCS Communications, Inc. Mr. Carter also has extensive senior management experience in the wireless and retail industry and spent ten years in public accounting. He is a certified public accountant. Mr. Carter received a Bachelor of Science degree from the University of Colorado with a major in accounting.

Peter A. Ewens

Mr. Ewens serves as our Executive Vice President, Corporate Strategy. He leads the Company’s corporate strategy, business development and M&A activities, which include spectrum strategy and acquisitions and co-brand partnerships. Mr. Ewens has also served as Executive Vice President and Chief Strategy Officer of T-Mobile USA since July 2010. From April 2008 until July 2010, Mr. Ewens was Senior Vice President, Corporate Strategy at T-Mobile USA. Before joining T-Mobile USA, Mr. Ewens was Vice President of OEM Business at Sun Microsystems, a computer software and information technology services company, from June 2006 through March 2008. Before that, Mr. Ewens was a partner at McKinsey & Company, a global management consulting firm. Mr. Ewens received a Master of Science in Management from the Sloan School at Massachusetts Institute of Technology, and Master’s and bachelor’s degrees in Electrical Engineering from the University of Toronto.

Thomas C. Keys

Mr. Keys serves as our President, MetroPCS, and is responsible for our MetroPCS business. Previously, Mr. Keys served as our Executive Vice President and Chief Operating Officer, MetroPCS Business, from April 2013 to February 2015. Mr. Keys served as MetroPCS Communications Inc.’s President from May 2011 until the consummation of the Business Combination, and as Chief Operating Officer since June 2007. Mr. Keys also served as MetroPCS Communications Inc.’s President from June 2007 to December 2007, Senior Vice President, Market Operations, West, from January 2007 until June 2007, and as Vice President and General Manager, Dallas, from April 2005 until January 2007. Mr. Keys received a Bachelor of Arts degree from the State University of New York at Oswego, and a Master of Arts from Syracuse University.

David A. Miller

Mr. Miller serves as our Executive Vice President, General Counsel and Secretary. Mr. Miller oversees all legal affairs and government affairs functions of the Company. Mr. Miller has also served as T-Mobile USA’s Chief Legal Officer, Executive Vice President, General Counsel and Secretary. Mr. Miller was appointed Senior Vice President and General

Counsel of T-Mobile USA in April 2002 and Executive Vice President in January 2011. Previously, Mr. Miller served as Director of Legal Affairs for Western Wireless (a predecessor to T-Mobile USA) from March 1995 to May 1999, and he became Vice President of Legal Affairs of VoiceStream in May 1999 following its spin-off from Western Wireless. VoiceStream was acquired by Deutsche Telekom in May 2001, when it became T-Mobile USA. Prior to joining Western Wireless, Mr. Miller was an attorney with the law firm of Lane Powell and began his law career as an attorney with the firm McCutchen, Doyle, Brown and Enersen. Mr. Miller serves on the Board of Directors of the Competitive Carriers Association and is a member of its Executive Committee. Mr. Miller received a bachelor’s degree in Economics from the University of Washington and a Juris Doctor from Harvard Law School.

Neville R. Ray

Mr. Ray serves as our Executive Vice President and Chief Technology Officer. Mr. Ray joined T-Mobile USA (then VoiceStream) in April 2000 and since December 2010 has served as its Chief Technology Officer, responsible for the national management and development of the T-Mobile USA wireless network and the company’s information technology services and operations. Prior to joining T-Mobile USA, Mr. Ray served as Network Vice President for Pacific Bell Mobile Services. He currently serves on the Board of Directors of Next Generation Mobile Networks Alliance, a mobile telecommunications association of mobile operators, vendors, manufacturers and research institutes, and as the Chairperson of the Board of Governors of 5G Americas, a mobile telecommunications

association of mobile operators, vendors, and manufacturers. Both associations have a focus on the advancement and development of 5G technologies and services. He has previously served as a member of the National Telecommunications and Information Administration’s Commerce Spectrum Management Advisory Committee and the Federal Communications Commission’s Communications Security, Reliability and Interoperability Council. Mr. Ray is an honors graduate of City, University of London and a member of the Institution of Electrical and Electronic Engineers and the Institution of Civil Engineers.

Elizabeth A. McAuliffe

Ms. McAuliffe serves as our Executive Vice President, Human Resources. Ms. McAuliffe is responsible for leading the human resources function that supports our employees across the country. From January 2014 to June 2016 she served as Senior Vice President of Total Rewards and Operations, encompassing leadership of all compensation, Rewards & Recognition, benefits, payroll, human resources systems and human resources operations. From June 2013 to January 2014, she served as Vice President, CHRO Regions, at Providence Health & Services, a nonprofit health system. From January 2011 to June 2013 she served as Senior Vice President, Human Resources at T-Mobile. Prior to joining T-Mobile, Ms. McAuliffe held various positions at Starbucks Coffee Company, a coffee retailer, in both the Law & Corporate Affairs department and the Human Resources department. Ms. McAuliffe received a bachelor’s degree from the University of Massachusetts, Amherst and a Juris Doctor from Northeastern University School of Law.

The Audit Committee has appointed PricewaterhouseCoopers LLP to serve as our independent registered public accounting firm for the fiscal year ending December 31, 2018. Although ratification of the appointment of PricewaterhouseCoopers LLP by our stockholders is not required, the Board is submitting the selection of PricewaterhouseCoopers LLP to our stockholders for ratification as a matter of good corporate governance. If the selection is not ratified, the Audit Committee will consider whether it is appropriate to select another independent registered public accounting firm.

We expect representatives of PricewaterhouseCoopers LLP to be present at the Annual Meeting. They will have an opportunity to make a statement if they so desire and are expected to be available to respond to appropriate questions by stockholders.

		Our Board of Directors recommends a vote FOR the ratification of PricewaterhouseCoopers LLP as the Company’s independent registered public accounting firm for fiscal year 2018

Required Vote

The affirmative vote of a majority of the votes cast is required to approve this proposal. If the stockholders do not ratify the appointment of PricewaterhouseCoopers LLP, the Audit Committee will reconsider the appointment but is under no obligation to appoint a different independent registered public accounting firm.

Pre-Approval Process

The Audit Committee is responsible for reviewing and, if appropriate, pre-approving all audit, audit-related and non-audit services to be performed by our independent registered public accounting firm. The Audit Committee charter authorizes the Audit Committee to establish a policy and related procedures regarding the pre-approval of audit, audit-related and non-audit services to be performed by our independent registered public accounting firm.

The Audit Committee has delegated its pre-approval authority to the Chair of the Audit Committee, who is authorized to pre-approve services to be performed by our independent registered public accounting firm and the compensation to be paid for such services if it is impracticable to delay the review and approval of such services and compensation until the next regularly-scheduled meeting of the Audit Committee, provided that in such case the Chair shall provide a report to the Audit Committee at its next regularly-scheduled meeting of any services and compensation approved by the Chair pursuant to the delegated authority.

Fees Paid to PricewaterhouseCoopers LLP

PricewaterhouseCoopers LLP was paid the following fees for services rendered during fiscal years 2017 and 2016, all of which were approved in conformity with the Audit Committee’s pre-approval process, as described above under “Pre-Approval Process”:

Audit Committee Report

In the performance of its oversight responsibilities, the Audit Committee (1) reviewed and discussed with management and the independent registered public accounting firm the Company’s audited financial statements for the fiscal year ended December 31, 2017; (2) discussed with the Company’s independent registered public accounting firm the matters required to be discussed by the Public Company Accounting Oversight Board (the “PCAOB”) Auditing Standard No. 1301, Communications with Audit Committees; (3) received the written disclosures and the letter from the Company’s independent registered public accounting firm required by the applicable requirements of the PCAOB regarding the independent accountant’s communications with the Audit Committee regarding independence; and (4) discussed with the Company’s independent registered public accounting firm any relationships that may impact its objectivity and independence and satisfied itself as to the firm’s independence.

Company management is responsible for the assessment and determination of risks associated with the Company’s business, financial reporting, operations and contractual obligations. The Audit Committee, together with the Board of Directors, is responsible for oversight of the Company’s management of risks. As part of its responsibilities for oversight of the Company’s management of risks, the Audit Committee has reviewed and discussed the Company’s enterprise-wide risk assessment, and the Company’s policies with respect to risk assessment and risk management, including discussions of individual risk areas as well as an annual summary of the overall process.

The Audit Committee has discussed with the Company’s Internal Audit Department and its independent registered public accounting firm the overall scope of and plans for their respective audits. The Committee regularly meets with the head of the Company’s Internal Audit Department and representatives of the independent registered public accounting firm, in regular and executive sessions, to discuss the results of their examinations, their evaluations of the Company’s internal controls, and the overall quality of the Company’s financial reporting and compliance programs.

Management is responsible for the Company’s financial reporting process, including establishing and maintaining adequate internal control over financial reporting and the preparation of the Company’s financial statements. The Company’s independent registered public accounting firm is responsible for performing an independent audit of the Company’s consolidated financial statements and expressing an opinion on the conformity of the Company’s audited financial statements with U.S. generally accepted accounting principles. The Company’s independent

registered public accounting firm also is responsible for performing an independent audit of the effectiveness of the Company’s internal control over financial reporting and issuing a report thereon. We rely, without independent verification, on the information provided to us and on the representations made by management and the Company’s independent registered public accounting firm. Based on the review and discussion and the representations made by management and the Company’s independent registered public accounting firm, the Audit Committee recommended to the Board of Directors that the audited consolidated financial statements for the fiscal year ended December 31, 2017 be included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017.

The Audit Committee:

Srikant M. Datar, Ph.D., Chairman

W. Michael Barnes, Ph.D.

Kelvin R. Westbrook

The material contained in this Audit Committee Report does not constitute soliciting material, is not deemed filed with the SEC, and is not incorporated by reference into any other Company filing under the Securities Act of 1933, as amended, or the Exchange Act, whether made on, before, or after the date of this Proxy Statement and irrespective of any general incorporation language in such filing, except to the extent that the Company specifically incorporates the Audit Committee Report by reference therein.

Factors Considered in Determining Executive Compensation

Compensation Consultant and Management

The Compensation Committee sets compensation levels based on the skills, experience and achievements of each executive officer, taking into account market analysis, input by its compensation consultant and the compensation recommendations of our Chief Executive Officer, except with respect to his own position. The Chief Executive Officer provides recommended target annual compensation adjustments for the Named Executive Officers to base salaries, target annual short-term incentive opportunity and target long-term incentive opportunity. The Compensation Committee believes that input from both its independent compensation consultant and our Chief Executive Officer provides useful information and points of view to assist the Compensation Committee in determining appropriate compensation.

Market Analysis

We use comparative executive officer compensation data publicly disclosed by a peer group of public companies in addition to compensation survey data to evaluate the competitiveness of our executive officer compensation and to guide the compensation for newly hired executive officers. We believe a competitive total compensation package is necessary to attract and retain an executive management team with the appropriate abilities and experience required to lead the Company and execute on our strategic business plan. In analyzing this information, we compare our executive compensation program as a whole to the programs of our peer group companies and compare the pay of our individual executives to that of the

executive officers of our peer group companies if we believe the positions are sufficiently similar to make meaningful comparisons. We do not target a specific percentile in the range of comparative data for each individual or for each component of compensation. In determining the amount of base salary, target incentive award and level of equity compensation for each Named Executive Officer, we review the comparative compensation data and consider each executive’s level of responsibility, prior experience, past job performance, contribution to the Company’s success and results achieved. The Compensation Committee exercises its business judgment and discretion and does not apply formulas or assign these factors specific mathematical weights.

Executive Compensation Peer Group

We select our peer group based on similarity to us in terms of relative size of revenue and market capitalization, industry and the ability to compete with us for talent at the executive officer level. The Compensation Committee reviews the Company’s peer group on an annual basis. Initially, our 2017 peer group was the same as our 2016 peer group. This peer group, which is described below, was used to set compensation for 2017. In November 2017, upon its acquisition by CenturyLink, Level 3 Communications was removed from our peer group. T-Mobile was ranked near the median of the peer group for 2017 both in terms of revenue and market capitalization.

The following chart shows T-Mobile’s 2017 peer group of 14 companies and each such company’s revenue as of fiscal year-end and market capitalization as of December 31, 2017 (other than with respect to Level3 Communications, which, as noted, was removed from our peer group in November 2017 due to its acquisition). Our peer group for 2018 has not changed.

Analysis of Executive Officer Compensation

The key components of our annual target total compensation package for executive officers are base salary, annual cash-based short-term incentive and long-term incentive awards, including performance-based restricted stock units (“PRSUs”) and time-based restricted stock units (“RSUs”).

Target Total Direct Compensation

The Compensation Committee reviews the compensation of the Named Executive Officers based on a market analysis prepared by management in partnership with the Compensation Committee’s independent

compensation consultant. Based on the Compensation Committee’s assessment of each Named Executive Officer in relation to peer and survey market data as well as the executive officer’s contribution to the Company’s ongoing strategy, the Compensation Committee increased the total target compensation of each of our Named Executive Officers for 2017, including increases to base salary, annual short-term incentive opportunity and target long-term incentive opportunity. Increases to target compensation supported the continued retention and engagement of our Named Executive Officers.

The following table shows the 2017 target total direct compensation established for each Named Executive Officer.

Annual Base Salaries

Base salary is designed to provide a competitive fixed component of income. Base salaries for our Named Executive Officers are set by the Compensation Committee, with assistance from the independent compensation consultant, after consideration of various factors including individual performance, executive experience and skill set and market data. In particular, the Compensation Committee focuses on how base salary levels may impact the market competitiveness of an executive’s total compensation opportunity. See further discussion under “— Factors Considered in Determining Executive Compensation-Market Analysis” above.

Annual Short-Term Incentives

Our executive officers are eligible for annual cash-based short-term incentives under the 2013 Omnibus Incentive Plan. The Compensation Committee sets the target value of each executive’s short-term incentive award opportunity as a percentage of the executive’s base salary. The final award is based on the eligible base earnings for the performance period. Award opportunities for each metric evaluated under the plan are established at threshold, target and maximum levels. The maximum level for each metric is capped at 200% of target. The 2017 short-term incentive plan (the “2017 STIP”) awards for executive officers, including the Named Executive Officers, were based entirely on Company performance, which was measured by: Total Service Revenue, Branded Net Additions (Total Branded Customer Additions), Adjusted EBITDA, and Operating Free Cash Flow. Adjusted EBITDA and Operating Free Cash Flow are non-GAAP measures and Operating Free Cash Flow is not provided in our earnings materials. Please see Appendix A for more information on how these measures are calculated.

Long-Term Incentives

We grant our executive officers long-term incentive compensation in the form of performance-based RSUs and time-based RSUs under the 2013 Omnibus Incentive Plan. Performance-based RSUs are measured based on our relative total shareholder return (“RTSR”) over a three-year performance period. We believe it is an appropriate performance measure because RTSR inherently reflects relevant financial and operational results as share price is a reflection of our current and expected future performance and directly links a significant portion of executive officer compensation to shareholder value creation.

Long-Term Incentive Awards Granted in 2017

On February 25, 2017, we granted long-term incentive awards to the Named Executive Officers. With the exception of Mr. Legere, the Named Executive Officers received half of the aggregate value of their 2017 long-term incentive awards in the form of performance-based RSUs and half of such value in the form of time-based RSUs. We believe this mix

emphasizes long-term Company performance as well as the retention and engagement of the Named Executive Officers. To further align Mr. Legere’s compensation with stockholder value creation, Mr. Legere’s 2017 long-term incentive award had a greater emphasis on performance-based RSUs, with approximately 3/4 of the award consisting of performance-based RSUs (including his True-Up PRSUs described below) and roughly 1/4 consisting of time-based RSUs. In addition to their annual awards, each of Messrs. Legere, Sievert and Carter were granted one-time special long-term incentive awards, as discussed below under “— Special Equity Awards in 2017.” Time-based RSU awards for 2017 generally vest annually in three equal tranches beginning February 2018, subject to the Named Executive Officer’s continued service through the applicable vesting date. The performance-based RSU awards for 2017 generally cliff vest at the conclusion of the three-year performance period ending February 25, 2020, subject to the Named Executive Officer’s continued service through the vesting date and based on the level of RTSR attained during the performance period.

The peer group for the 2017 performance-based RSU awards against which RTSR is measured originally consisted of the following 15 companies: AT&T, CenturyLink, Charter Communications, Cisco Systems, Comcast, Dish Network, Frontier Communications, Intel, Level 3 Communications, Liberty Global, Microsoft, Motorola Solutions, Qualcomm, Sprint, and Verizon Communications. Under the terms of the award, if one or more members of the peer group cease to be a publicly traded entity during the performance period, then that company will be removed from the peer group. In such an event, no additional companies will be added to the peer group for purposes of determining any earned performance-based RSU awards. Level 3

Communications was removed from the peer group upon acquisition by CenturyLink on November 1, 2017, and will not be taken into account in measuring RTSR with respect to the 2017 performance-based RSU awards.

The total 2017 target long-term incentive grant value and the number of performance-based and time-based RSUs awarded are shown below for each Named Executive Officer. The number of RSUs awarded was established as the total grant-date target value multiplied by the award mix and divided by the average closing price of our common stock for the 30 calendar-day period ending five business days prior to the grant date.

Special Equity Awards in 2017

In April 2017, the Company entered into an amended and restated employment agreement with Mr. Legere, pursuant to which Mr. Legere was granted a one-time award of performance-based RSUs with a target value equal to $3,000,000 (the “True-Up PRSUs”). The award was intended to bring Mr. Legere’s 2017 annual award to $15,000,000 pursuant to his amended and restated employment agreement. The True-Up PRSUs are subject to the same vesting schedule and other terms and conditions applicable to the annual award of performance-based RSUs granted to Mr. Legere on February 25, 2017 (see “— Long-Term Incentive Awards Granted in 2017” above for additional information).

In February 2017, to recognize Mr. Sievert’s role and incentivize continued strong performance, the Company entered into an amended and restated compensation term sheet with Mr. Sievert, pursuant to which he was granted a one-time award of performance-based RSUs with a target value equal to $3,562,500 and a one-time award of time-based RSUs with a target value equal to $3,562,500. Subject to Mr. Sievert’s continued employment through such date, the performance-based RSUs cliff vest at the conclusion of a two-year performance period ending February 25, 2019 (based on the level of RTSR attained during the performance period against our peer group) and the time-based RSUs vest in full on February 25, 2019.

In December 2017, to recognize Mr. Carter’s role and incentivize continued strong performance, the Company entered into an amended and restated employment agreement with Mr. Carter, pursuant to which he was granted a one-time award of time-based RSUs with a target value of $2,500,000. Subject to Mr. Carter’s continued employment through such date, the award vests in full on March 1, 2019.

The annual and special time-based and performance-based RSUs granted during 2017 are subject to accelerated vesting in certain circumstances as described below under “— Potential Payments upon Termination or in Connection with a Change in Control”.

Perquisites

We generally do not provide perquisites to any executive officer, including the Named Executive Officers, beyond what all other employees may be eligible to receive. In 2017, we provided personal security for Mr. Legere due to the range of security issues encountered by chief executive officers of large public companies, particularly with respect to high-profile chief executive officers such as Mr. Legere. For fiscal year 2017, we paid approximately $48,000 toward Mr. Legere’s personal security. We also

reimbursed Messrs. Legere, Sievert and Carter for legal fees and expenses (capped at $25,000 for each executive) incurred in connection with the negotiation and preparation of each such executive’s amended and restated employment agreement or term sheet, as applicable. In 2017, the Company also permitted the spouses of executive officers, including the Named Executive Officers, to attend one Board meeting and paid for certain incremental costs (excluding travel costs) associated with such attendance.

Comprehensive Benefits Package

We provide a competitive benefits package to all full-time employees, including the Named Executive Officers, that includes health and welfare benefits, such as medical, dental, vision care, disability insurance, life insurance benefits and a 401(k) savings plan (with an employer match up to 4%). We provide a non-qualified deferred compensation plan under which eligible participants may defer up to 75% of their base salary and 100% of their short-term incentive and annual RSUs. We do not provide any employer matching or discretionary allocations under the non-qualified deferred compensation plan.

Severance and Change-in-Control Benefits

We provide severance pay and other termination benefits to eligible executive officers, including the Named Executive Officers, whose employment is terminated, including due to corporate restructuring, and, in some cases, due to involuntary termination by us without cause, due to our non-renewal of the executive’s employment term or due to the voluntary termination by the executive for good reason. These arrangements provide security of transition income and benefit replacement that allow such executives to focus on our prospective business priorities that create value for stockholders. We believe the level of severance and termination benefits provided by these arrangements is consistent with the practices of our peer group and is necessary to attract and retain key employees. These benefits are provided pursuant to our Severance Guidelines, Executive Continuity Plan, 2013 Omnibus Incentive Plan, long-term incentive award agreements and, for each of Messrs. Legere, Sievert and Carter, pursuant to a written employment agreement or term sheet, as applicable. These arrangements do not include any gross up for excise taxes imposed as a result of severance or other payments that are deemed made in connection with a change in control. The potential payments and benefits available under these arrangements are discussed further under “ — Potential Payments upon Termination or in Connection with a Change in Control.”

Other Matters

Tax and Accounting Considerations

Section 162(m) of the Code. The Internal Revenue Code (the “Code”) Section 162(m) generally disallows an income tax deduction to public companies for annual compensation in excess of $1 million paid to the chief executive officer and other “covered employees.” For taxable years beginning on or before December 31, 2017, this deduction limit included an exception for “qualified performance-based compensation”. The recently-enacted Tax Act amended certain provisions of Code Section 162(m), including eliminating the exemption for “qualified performance-based compensation” for tax years beginning after December 31, 2017. The Tax Act includes a grandfather provision, pursuant to which compensation that is provided pursuant to a written binding contract in effect on November 2, 2017, and which has not been modified in any material respect on or after that date, will not be subject to the amendments made to Code Section 162(m) by the Tax Act. We believe that maintaining the discretion to evaluate the performance of our executive officers through the use of performance-based compensation is an important part of our responsibilities and benefits our stockholders, even if it may be non-deductible under Code Section 162(m). The Compensation Committee has historically considered the potential impact of Code Section 162(m) as well as other tax and accounting consequences when developing and implementing the Company’s executive compensation programs. However, the Compensation Committee retains the discretion and flexibility to design and administer compensation programs that are in the best interests of the Company and its stockholders, and, in light of the repeal of the performance-based compensation exception to Code Section 162(m), the Compensation Committee may in the future approve compensation that would not have qualified as performance-based compensation under Code Section 162(m) as in effect prior to the Tax Act.

Section 280G of the Code. Code Section 280G disallows a tax deduction with respect to excess parachute payments to certain executives of companies which undergo a change in control. In addition, Code Section 4999 imposes a 20% excise tax on the individual with respect to the excess parachute payment. Parachute payments are compensation linked to or triggered by a change in control and may include, but are not limited to, bonus payments, severance payments, certain fringe benefits, and payments and acceleration of vesting from long-term incentive plans including stock options and other equity-based compensation. Excess parachute payments are parachute payments that exceed a threshold determined under Code Section 280G based on the executive’s prior compensation. As discussed above, we do not provide tax gross-ups on income attributable to change in control and other executive arrangements.

Section 409A of the Code. Code Section 409A requires that “nonqualified deferred compensation” be deferred and paid under plans or arrangements that satisfy the requirements of the statute with respect to the timing of deferral elections, timing of payments and certain other matters. Failure to satisfy these requirements can expose employees and directors to accelerated income tax liabilities, substantial additional taxes and interest on their vested compensation under such plans. Accordingly, as a general matter, it is our intention to design and administer our compensation and benefit plans and arrangements for all of our employees and directors, including our Named Executive Officers, so that they are either exempt from, or satisfy the requirements of, Code Section 409A.

Accounting for Stock-Based Compensation. We follow Financial Accounting Standards Board Accounting Standards Codification Topic 718, or ASC Topic 718, for stock-based compensation awards. ASC Topic 718 requires companies to calculate the grant date “fair value” of their stock-based awards using a variety of assumptions. ASC Topic 718 also requires companies to recognize the compensation cost of their stock-based awards in their income statements over the period that an employee is required to render service in exchange for the award. Grants of performance-based RSUs, time-based RSUs and other equity-based awards under equity incentive award plans have been and will be accounted for under ASC Topic 718. We expect that we will regularly consider the accounting implications of significant compensation decisions, especially in connection with decisions that relate to our equity incentive award plans and programs. As accounting standards change, we may revise certain programs to appropriately align accounting expenses of our equity awards with our overall executive compensation philosophy and objectives. For further information on our accounting for our stock-based compensation awards, refer to our Annual Report on Form 10-K for the year ended December 31, 2017.

Securities Trading Policy

Our policy on securities trading prohibits our directors, officers and employees from trading in our securities during certain designated blackout periods and otherwise while they are aware of material non-public information, and from engaging in hedging transactions or short sales and trading in options with respect to our securities. The policy also prohibits holding our securities in a margin account or pledging our securities as collateral for a loan.

Clawback Provisions

In 2014, the Compensation Committee adopted a policy of recoupment of compensation in certain circumstances. The policy provides that in the event the Company issues a restatement of its financial statements due to its material noncompliance with financial reporting requirements under U.S. securities laws, the Company will, to the extent permitted by governing law, require reimbursement from current and former executive officers for excess incentive compensation received at any time during the three-year period preceding the date on which the Company is required to prepare the accounting restatement if a lower payment would have occurred based on the restated results, regardless of whether the executive officer engaged in misconduct or otherwise caused or contributed to the requirement for the restatement. The policy is administered by the Section 16 Subcommittee, which has the sole discretion to seek recovery from an executive officer and may consider whether seeking recovery would be in the best interests of the Company, including the costs and benefits of seeking recovery and whether doing so may prejudice the interests of the Company, including in any related proceeding or investigation. All awards granted under the 2013 Omnibus Incentive Plan are subject to the requirements of Section 954 of the Dodd-Frank Act regarding the recovery of erroneously awarded compensation as well as any implementing rules and regulations under the Dodd-Frank Act, any policies adopted by the Company to implement such requirement, and any other compensation recovery policies that may be adopted from time to time by the Company.

Stock Ownership Guidelines and Broad-Based Stock Ownership

Under our stock ownership guidelines, the Chief Executive Officer and all executive officers reporting to the Chief Executive Officer are expected to acquire and maintain ownership of shares of common stock equal in value to a specified multiple of the executive officer’s base salary measured as of the later of (i) the date we adopted the stock ownership guidelines (May 1, 2013) and (ii) the date on which he or she became an executive officer.

Each executive officer is expected to meet the ownership guidelines within the later of (i) five years from the date we adopted the guidelines and (ii) the date on which he or she became an executive officer, and is expected to retain at least 50% of the net shares of common stock acquired through equity awards until the ownership thresholds are met.

We believe that all employees should have a stake in the Company’s performance. Accordingly, we utilize a Company-wide annual equity award program. In addition, we implemented an Employee Stock Purchase Plan (“ESPP”) in 2015 to provide employees with a cost-effective vehicle to purchase stock.

Equity Granting Practices

The Compensation Committee has adopted an equity grant policy pursuant to which the Compensation Committee (or a subcommittee) may approve annual grants to executive officers and other members of the executive leadership team at a specified time each year. In addition to the annual grants, equity awards may be granted on a quarterly basis to new hires. We may also grant supplemental equity awards from time to time to retain high-performing leaders, reward exceptional performance or recognize expanded responsibility. The Compensation Committee has delegated authority to the Company’s Executive Vice President, Human Resources, subject to certain terms and limitations as established by the Compensation Committee, to grant awards to employees who are not Section 16 officers.

Results of Stockholder Advisory Approval of Named Executive Officer Compensation

At the 2017 Annual Meeting of Stockholders, stockholders were asked to approve, on an advisory basis, the Named Executive Officer compensation for 2016 as reported in the proxy statement. This say-on-pay proposal was approved by over 99% of the shares present and entitled to vote, and the Compensation Committee believes this affirms our stockholders’ strong support of our executive compensation program.

Accordingly, while the Compensation Committee considered the results of the 2017 advisory vote along with stockholder input and other factors discussed in this CD&A, it concluded that no changes to our compensation policies and practices were warranted in response to the stockholder advisory vote. The Board has previously determined to hold advisory say-on-pay votes every three years. Accordingly, the next advisory say-on-pay stockholder vote will occur in connection with the 2020 Annual Meeting of Stockholders.