EX-10.1



 Exhibit 10.1 

SUPPORT AGREEMENT 
 This
SUPPORT AGREEMENT, dated as of April 29, 2018 (this “Agreement”), is made by and among Deutsche Telekom AG, an Aktiengesellschaft organized and existing under the Laws of the Federal Republic of Germany
(“DT”), Deutsche Telekom Holding B.V., a besloten vennootschap met beperkte aansprakelijkheid organized and existing under the laws of the Netherlands and an indirect wholly owned subsidiary of DT (the “DT
Stockholder”), Sprint Corporation, a Delaware corporation (“Sprint”), and SoftBank Group Corp., a Japanese kabushiki kaisha (“SoftBank”). 

W I T N E S E T H 

WHEREAS, on April 29, 2018, T-Mobile U.S., Inc.
(“T-Mobile”), Huron Merger Sub LLC, a Delaware limited liability company (“Merger Company”), Superior Merger Sub Corporation, a Delaware corporation (“Merger
Sub”), Sprint, and, for the limited purposes set forth therein, DT, DT Holding and SoftBank, entered into a Business Combination Agreement (the “Business Combination Agreement”), pursuant to which, among other things, the
parties agreed to effect a business combination through the SoftBank US Mergers (as defined in the Business Combination Agreement) and the merger of Merger Sub with and into Sprint, with Sprint continuing as the surviving corporation and as a wholly
owned Subsidiary of T-Mobile (the “Merger”), upon the terms and subject to the conditions set forth therein; 

WHEREAS, as of the date hereof, the DT Stockholder is the Beneficial Owner of, and has the right to vote and consent with respect to, that
number of shares of common stock, par value $0.00001 per share, of T-Mobile (the “T-Mobile Common Stock”) set forth in
Section 4.4 of this Agreement (such shares of T-Mobile Common Stock, together with all other shares of T-Mobile Common Stock with respect to
which the DT Stockholder or DT or any other Controlled Affiliate of DT acquires Beneficial Ownership after the date hereof and prior to the Expiration Time and together with all other securities issued to DT or the DT Stockholder in respect of such T-Mobile Common Stock or into which shares of such T-Mobile Common Stock may be converted or exchanged in connection with stock dividends or distributions, combinations or any
similar recapitalizations on or after the date hereof, collectively, the “Shares”); and 
 WHEREAS, Sprint and SoftBank
desire that DT and the DT Stockholder agree, and DT and the DT Stockholder are willing to agree, on the terms and subject to the conditions set forth herein, not to Transfer (as defined below) any of the Shares, and to vote or consent all of the
Shares in a manner so as to facilitate the consummation of the SoftBank US Mergers, the Merger and the other transactions contemplated by the Business Combination Agreement. 

NOW, THEREFORE, in consideration of the mutual covenants and agreements set forth herein, and for other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged, the parties hereto, intending to be legally bound, hereby agree as follows: 
 1.
    Definitions and Related Matters. 
 1.1    Definitions. This Agreement is the
“DT Support Agreement” as defined in the Business Combination Agreement. Capitalized terms used but not otherwise defined herein shall have the respective meanings ascribed to such terms in the Business Combination








 
Agreement. As used in this Agreement, the following terms shall have the meanings indicated below: 

“Affiliate” shall mean, with respect to any Person, a Person that, directly or indirectly through one or more intermediaries,
Controls, is Controlled by, or is under common Control with such Person; provided that, for purposes of this Agreement, none of T-Mobile, Sprint, SoftBank or their respective Subsidiaries shall be
deemed to be an Affiliate of DT or the DT Stockholder. 
 “Agreement” shall have the meaning set forth in the Preamble.

 “Beneficially Own” shall mean, with respect to any securities, (a) having “beneficial ownership” of such
securities for purposes of Rule 13d-3 or 13d-5 under the Exchange Act (or any successor statute or regulation), (b) having the right to become the Beneficial Owner of
such securities (whether such right is exercisable immediately or only after the passage of time or the occurrence of conditions) pursuant to any agreement, arrangement or understanding, or upon the exercise of conversion rights, exchange rights,
rights, warrants or options, or otherwise, or (c) having an exercise or conversion privilege or a settlement payment or mechanism with respect to any option, warrant, convertible security, stock appreciation right, swap agreement or other
security, contract right or derivative position, whether or not currently exercisable, at a price related to the value of the securities for which Beneficial Ownership is being determined or a value determined in whole or part with reference to, or
derived in whole or in part from, the value of the securities for which Beneficial Ownership is being determined that increases in value as the value of the securities for which Beneficial Ownership is being determined increases or that provides to
the holder an opportunity, directly or indirectly, to profit or share in any profit derived from any increase in the value of the securities for which Beneficial Ownership is being determined (excluding any interests, rights, options or other
securities set forth in Rule 16a-1(c)(1)-(5) or (7) promulgated pursuant to the Exchange Act). 

“Business Combination Agreement” shall have the meaning set forth in the Recitals. 

“Control” shall mean the possession, direct or indirect, of the power to direct, or cause the direction of, the management
and policies of a Person, whether through the ownership of voting securities, voting equity, limited liability company interests, general partner interests, or other voting interests, by contract or otherwise. 

“DT” shall have the meaning set forth in the Preamble. 

“DT Stockholder” shall have the meaning set forth in the Preamble. 

“Expiration Time” shall mean the earliest to occur of (a) the Effective Time and (b) the termination of the
Business Combination Agreement in accordance with its terms. 
 “Form S-4” shall
have the meaning set forth in Section 2. 
 “Merger” shall have the meaning set forth in the
Recitals. 

  
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 “Merger Sub” shall have the meaning set forth in the Recitals. 

“Organizational Documents” shall mean, with respect to any Person, such Person’s articles or certificate of association,
incorporation, formation or organization, bylaws, limited liability company agreement, partnership agreement or other constituent document or documents, each in its currently effective form as amended from time to time. 

“Person” shall mean any individual, corporation (including
not-for-profit), general or limited partnership, limited liability company, joint venture, estate, trust, association, organization, governmental entity or other entity
of any kind or nature. 
 “Shares” shall have the meaning set forth in the Recitals. 

“Subsidiary” shall mean, with respect to any Person, any entity, whether incorporated or unincorporated, of which
(i) voting power to elect a majority of the board of directors, management committee or others performing similar functions with respect to such other Person is held by the first mentioned Person and/or by any one or more of its Subsidiaries,
(ii) a general partnership interest is held by such first mentioned Person and/or by any one or more of its Subsidiaries (excluding partnerships where such first mentioned Person (A) does not Beneficially Own a majority of the general
partnership interests or voting interests and (B) does not otherwise Control such entity, directly or indirectly, by contract, arrangement or otherwise), or (iii) at least 50% of the equity interests of such other Person is, directly or
indirectly, owned or Controlled by such first mentioned Person and/or by any one or more of its Subsidiaries. 
 “SoftBank”
shall have the meaning set forth in the Preamble. 
 “Sprint” shall have the meaning set forth in the Preamble. 

“T-Mobile” shall have the meaning set forth in the Recitals. 

“T-Mobile Common Stock” shall have the meaning set forth in the Recitals. 

“Transfer” shall mean, with respect to any Share, any direct or indirect sale, transfer, assignment, pledge, hypothecation,
mortgage, license, gift, creation of a security interest in or lien on, placement in trust (voting or otherwise), encumbrance or other disposition of such Share to any Person, including those by way of any
spin-off (such as through a dividend), hedging or derivative transactions, sale, transfer or assignment of a majority of the equity interest in, or sale, transfer or assignment of Control of, any Person
holding such Share, or otherwise; provided, however, that (i) the Transfer of equity interests in the DT Stockholder to another Person Controlled by DT shall not be deemed to be a Transfer, and (ii) any direct or indirect
sale, transfer, assignment, pledge, hypothecation, mortgage, license, gift, creation of a security interest in or lien on, placement in trust (voting or otherwise), encumbrance or other disposition of any security issued by DT, including by tender
or exchange offer, merger, amalgamation, plan of arrangement or consolidation or any similar transaction, shall not be deemed to be a Transfer of any Shares by DT or the DT Stockholder. 

1.2    Other Definitional Provisions. Unless the express context otherwise requires: (i) the words
“hereof”, “herein”, and “hereunder” and words of similar import, when 

  
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used in this Agreement, shall refer to this Agreement as a whole and not to any particular provision of this Agreement; (ii) the words “date hereof”, when used in this Agreement,
shall refer to the date set forth in the Preamble; (iii) the terms defined in the singular have a comparable meaning when used in the plural, and vice versa; (iv) the terms defined in the present tense have a comparable meaning when used
in the past tense, and vice versa; (v) any references herein to a specific Section, Schedule, Annex or Exhibit shall refer, respectively, to Sections, Schedules, Annexes or Exhibits of this Agreement; (vi) wherever the word
“include”, “includes”, or “including” is used in this Agreement, it shall be deemed to be followed by the words “without limitation”; (vii) references herein to any gender includes each other gender; and
(viii) the word “or” shall not be exclusive. 
 2.     Agreement to Consent and Approve. The DT
Stockholder agrees that, from the date hereof until the Expiration Time, promptly (and in any event within two business days) following receipt by it of a registration statement on Form S-4 in connection with
the issuance of the shares of T-Mobile Common Stock in the Merger Transactions, in which a joint consent solicitation statement with respect to the solicitation of consents from the stockholders of Sprint and T-Mobile in connection with the Sprint Stockholder Approval and the T-Mobile Stockholder Approval, respectively, is included as a prospectus (the “Form S-4”), which Form S-4 has been declared effective under the Securities Act by the SEC, the DT Stockholder shall execute and deliver a written consent approving the
adoption of the Business Combination Agreement, substantially in the form attached hereto as Exhibit A, with respect to all of its Shares entitled to consent thereto. Any such written consent shall be given in accordance with such procedures
relating thereto so as to ensure that it is duly counted for purposes of recording the results of such consent. The DT Stockholder shall not enter into any tender, voting or other agreement or arrangement with any Person prior to the Expiration
Time, directly or indirectly, to vote, grant a proxy or power of attorney or give instructions with respect to the voting of the Shares in any manner that is inconsistent with this Agreement or otherwise take any other action with respect to the
Shares that would in any way restrict, limit or interfere with the performance by the DT Stockholder of its obligations hereunder or the transactions contemplated hereby, including the approval of each of the
T-Mobile Share Issuance and the T-Mobile Charter Amendment. The DT Stockholder agrees that, from the date hereof until the Expiration Time, it shall vote or cause to be
voted (including by written consent) all of its Shares against (a) any T-Mobile Alternative Transaction and (b) any other action, agreement or transaction involving
T-Mobile that is intended, or would reasonably be expected, to impede, interfere with, delay, postpone, adversely affect or prevent the consummation of the Merger or the other transactions contemplated by the
Business Combination Agreement. Any attempt by the DT Stockholder to vote, or express consent or dissent with respect to (or otherwise to utilize the voting power of), its Shares in contravention of this Section 2 shall be
null and void ab initio. 
 3.     Agreement Not to Transfer or Encumber. The DT Stockholder hereby agrees
that, from the date hereof until the Expiration Time, it shall not (a) Transfer any Shares or (b) deposit any Shares into a voting trust or enter into a voting agreement or arrangement with respect to any Shares or grant a proxy or power
of attorney with respect thereto (other than pursuant to this Agreement); provided that the DT Stockholder may Transfer any Shares to any Controlled Affiliate of DT subject to compliance with Section 9.11. Any
Transfer or attempted Transfer of any Shares in violation of this Section 3 shall be null and void ab initio. 

  
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 4.     Representations, Warranties and Covenants of DT and the DT
Stockholder. DT and the DT Stockholder hereby represent and warrant to Sprint and SoftBank as follows: 
 4.1    DT
is an Aktiengesellschaft organized and existing under the Laws of the Federal Republic of Germany. The Deer Stockholder is a besloten vennootschap met beperkte aansprakelijkheid organized and existing under the laws of the
Netherlands 
 4.2    Each of DT and the DT Stockholder has all requisite power and authority to execute and deliver
this Agreement and to perform its obligations hereunder. The execution and delivery by each of DT and the DT Stockholder of this Agreement and the performance of its obligations hereunder have been duly authorized by all necessary action of DT and
the DT Stockholder, as applicable. This Agreement has been duly executed and delivered by each of DT and the DT Stockholder and, assuming the due authorization, execution and delivery of this Agreement by Sprint and SoftBank, constitutes the legal,
valid and binding obligation of DT and the DT Stockholder, as applicable, enforceable against it in accordance with its terms, except as limited by the Enforceability Exceptions. 

4.3    The execution and delivery of this Agreement by each of DT and the DT Stockholder and the performance of its
obligations hereunder will not constitute or result in (a) a breach or violation of, or a default under, the Organizational Documents of DT or the DT Stockholder, (b) a breach or violation of, a termination (or right of termination) or
default under, the creation or acceleration of any obligations under, or the creation of a Lien on any of the assets of DT or the DT Stockholder (with or without notice, lapse of time or both) pursuant to, any agreement, lease, license, contract,
note, mortgage, indenture, arrangement or other obligation binding upon DT or the DT Stockholder, or (c) a conflict with, breach or violation of any Law applicable to DT or the DT Stockholder or by which its properties are bound or affected,
except, in the case of clause (b) or (c), for any breach, violation, termination, default, creation or acceleration that would not, individually or in the aggregate, reasonably be expected to impair the ability of DT or the DT Stockholder to
perform its obligations under this Agreement on a timely basis. 
 4.4    As of the date hereof, (a) the DT
Stockholder (i) Beneficially Owns 538,590,941 shares of T-Mobile Common Stock free and clear of any and all Liens, other than those created by this Agreement, and (ii) has sole voting power over and
right to consent with respect to all of such shares of T-Mobile Common Stock and (b) DT and its Controlled Affiliates do not Beneficially Own any shares of capital stock or other voting or equity
securities or interests of T-Mobile, or any rights to purchase or acquire any such shares or other securities or interests, except for such shares of T-Mobile Common
Stock. 
 4.5    Except as contemplated by this Agreement, neither DT nor the DT Stockholder has entered into any
tender, voting or other agreement or arrangement with respect to any Shares or entered into any other contract relating to the voting of any Shares. Any and all proxies in respect of the Shares are revocable, and such proxies either have been
revoked prior to the date hereof or are hereby revoked. 
 4.6    As of the date hereof, there is no Action pending or,
to the knowledge of DT, threatened against or affecting DT or the DT Stockholder that, individually or in the 

  
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aggregate, would reasonably be expected to impair the ability of DT or the DT Stockholder to perform their obligations under this Agreement or to consummate the transactions contemplated by this
Agreement on a timely basis. 
 4.7    Each of DT and the DT Stockholder hereby (i) authorizes T-Mobile and Sprint to publish and disclose in any announcement or disclosure in connection with the transactions contemplated by the Business Combination Agreement, including the Consent Solicitation Statement and
the Form S-4 and any other applicable filings under the Exchange Act or the Securities Act, their identity and ownership of the Shares and the nature of their obligations under this Agreement, and
(ii) agrees that it shall promptly (A) furnish to T-Mobile and Sprint any information that T-Mobile or Sprint may reasonably request for the preparation of any
such announcement or disclosure and (B) notify T-Mobile and Sprint of any required corrections with respect to any written information supplied by it specifically for use in any such announcement or
disclosure, if and to the extent that any such information contained any untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary in order to make the statements therein, in light of the
circumstances under which they were made, not misleading. The parties hereto agree that T-Mobile is a third party beneficiary, and entitled to enforce the terms, of this Section 4.7.

 5.     Termination. Other than this Section 5 and
Section 9, which shall survive any termination of this Agreement, this Agreement shall terminate and shall have no further force or effect immediately as of and following the Expiration Time. Notwithstanding the foregoing,
nothing herein shall relieve any party hereto from liability for any breach of this Agreement that occurred prior to such termination. 
 6.
    Duties. DT and the DT Stockholder are entering into this Agreement solely in their capacities as Beneficial Owners of the Shares and nothing in this Agreement shall apply to any Person serving in his or her capacity as
a director or officer of T-Mobile. 
 7.     No Ownership Interest.
Nothing contained in this Agreement shall be deemed to vest in Sprint or SoftBank any direct or indirect ownership or incidence of ownership of or with respect to the Shares. All rights, ownership and economic benefits of and relating to the Shares
shall remain vested in and belong to DT and the DT Stockholder, as applicable, and neither Sprint nor SoftBank shall have the authority to direct DT or the DT Stockholder in the voting or disposition of any Shares, except as otherwise expressly
provided herein. 
 8.     No Obligation to Exercise. No provision of this Agreement shall require DT or the DT
Stockholder to exercise any option, warrant, convertible security or other security or contract right convertible into shares of T-Mobile Common Stock; provided, for the avoidance of doubt, that upon
any such exercise, the shares of T-Mobile Common Stock acquired by DT or the DT Stockholder pursuant thereto shall be Shares for all purposes hereunder. 

9.     Miscellaneous. 

9.1    Injunctive Relief. The parties acknowledge and agree that irreparable damage would occur in the event that
any of the provisions of this Agreement were not performed in accordance with their specific terms or were otherwise breached, and that monetary 

  
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damages, even if available, would not be an adequate remedy therefor. It is accordingly agreed that the parties shall be entitled to an injunction or injunctions to prevent breaches of this
Agreement and to enforce specifically the performance of terms and provisions of this Agreement in any court referred to in Section 9.5, without proof of actual damages (and each party hereby waives any requirement for the
securing or posting of any bond in connection with any such remedy), this being in addition to any other remedy to which they are entitled at law or in equity. The parties further agree not to assert that a remedy of specific enforcement is
unenforceable, invalid, contrary to law or inequitable for any reason, or to assert that a remedy of monetary damages would provide an adequate remedy for any such breach. 

9.2    Assignment. This Agreement shall be binding upon and inure to the benefit of the parties hereto and their
respective successors, heirs, legal representatives and permitted assigns. No party may directly or indirectly assign any of its rights or delegate any of its obligations under this Agreement, without the prior written consent of the other party;
provided that, without the written consent of the other parties, DT may assign any of its rights or obligations hereunder, in whole or in part, to any Person that will be a successor to or that will acquire Control of DT, whether by merger,
consolidation or sale of all or substantially all of its assets. Any purported direct or indirect assignment in violation of this Section 9.2 shall be null and void ab initio. 

9.3    Amendments and Waivers. No amendment, modification or discharge of this Agreement, and no waiver hereunder,
and no extension of time for the performance of any of the obligations hereunder, shall be valid or binding unless set forth in writing and duly executed by the parties. Any such waiver shall constitute a waiver only with respect to the specific
matter described in such writing and shall in no way impair the rights of any party granting any waiver in any other respect or at any other time. The waiver by any party of a breach of, or a default under, any of the provisions hereof, or to
exercise any right or privilege hereunder, shall not be construed as a waiver of any other breach or default of a similar nature, or as a waiver of any of such provisions, rights or privileges hereunder. Except as expressly provided in this
Agreement, the rights and remedies herein provided are cumulative and none is exclusive of any other, or of any rights or remedies that any party may otherwise have at law or in equity. 

9.4    Notices. All notices, requests, claims, demands and other communications under this Agreement shall be in
writing and shall be deemed given if delivered personally or delivered by electronic mail (which is confirmed) or sent by overnight courier (providing proof of delivery) to the parties at the following addresses (or at such other address for a party
as shall be specified by like notice): 
  

							
		 	(i)	  	if to SoftBank, to:
			
		 		  	SoftBank Group Corp.
		 		  	Tokyo Shiodome Bldg.
		 		  	1-9-1 Higashi-shimbashi
		 		  	Minato-ku, Tokyo 105-7303, Japan
		 		  	Attention:	  	    Corporate Officer, Head of Legal Unit
		 		  	Email:	  	    sbgrp-legalnotice@g.softbank.co.jp


  
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		 		  	with a copy (which shall not constitute notice) to:
			
		 		  	Morrison & Foerster LLP 425 Market Street
		 		  	San Francisco, CA 94015
		 		  	Attention:	  	    Robert S. Townsend
		 		  		  	    Brandon C. Parris
		 		  	Email:	  	    RTownsend@mofo.com
		 		  		  	    BParris@mofo.com
			
		 	(ii)	  	if to DT or the DT Stockholder, to:
			
		 		  	 Deutsche Telekom AG

Friedrich-Ebert-Allee 140
 53113 Bonn, Germany

		 		  	Attention:	  	    General Counsel
		 		  	Email:	  	    axel.luetzner@telekom.de
			
		 		  	with a copy (which shall not constitute notice) to:
			
		 		  	Wachtell, Lipton, Rosen & Katz 51 West 52nd Street
		 		  	New York, New York 10019
		 		  	Attention:	  	    Adam O. Emmerich
		 		  		  	    David K. Lam
		 		  	Email:	  	    AOEmmerich@wlrk.com
		 		  		  	    DKLam@wlrk.com
			
		 	(iii)	  	if to Sprint, to:
			
		 		  	Sprint Corporation
		 		  	6200 Sprint Parkway
		 		  	Overland Park, KS 66251
		 		  	Attention:	  	    Chief Legal Officer
		 		  	Email:	  	    office.chief.legal.officer@sprint.com
			
		 		  	with a copy (which shall not constitute notice) to:
			
		 		  	Morrison & Foerster LLP 425 Market Street
		 		  	San Francisco, CA 94015
		 		  	Attention:	  	    Robert S. Townsend
		 		  		  	    Brandon C. Parris


  
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		 		  	Email:	  	    RTownsend@mofo.com
		 		  		  	    BParris@mofo.com

 9.5    Governing Law; Jurisdiction; Forum; Waiver of Trial by Jury. THIS AGREEMENT
SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF DELAWARE, REGARDLESS OF THE LAWS THAT MIGHT OTHERWISE GOVERN UNDER ANY APPLICABLE PRINCIPLES OF CONFLICTS OF LAWS THEREOF. EACH PARTY ACKNOWLEDGES AND AGREES THAT ANY
CONTROVERSY WHICH MAY ARISE UNDER THIS AGREEMENT IS LIKELY TO INVOLVE COMPLICATED AND DIFFICULT ISSUES, AND THEREFORE IT HEREBY IRREVOCABLY AND UNCONDITIONALLY WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY RIGHT IT MAY HAVE TO A
TRIAL BY JURY IN RESPECT OF ANY LITIGATION DIRECTLY OR INDIRECTLY ARISING OUT OF OR RELATING TO THIS AGREEMENT AND ANY OF THE AGREEMENTS DELIVERED IN CONNECTION HEREWITH OR THE TRANSACTIONS CONTEMPLATED HEREBY OR THEREBY. EACH PARTY CERTIFIES AND
ACKNOWLEDGES THAT (A) NO REPRESENTATIVE, AGENT OR ATTORNEY OF ANY OTHER PARTY HAS REPRESENTED, EXPRESSLY OR OTHERWISE, THAT SUCH OTHER PARTY WOULD NOT, IN THE EVENT OF LITIGATION, SEEK TO ENFORCE THE FOREGOING WAIVER, (B) IT UNDERSTANDS
AND HAS CONSIDERED THE IMPLICATIONS OF SUCH WAIVER, (C) IT MAKES SUCH WAIVER VOLUNTARILY AND (D) IT HAS BEEN INDUCED TO ENTER INTO THIS AGREEMENT BY, AMONG OTHER THINGS, THE MUTUAL WAIVER AND CERTIFICATIONS IN THIS SECTION 9.5. In any
action between the parties arising out of or relating to this Agreement, each of the parties (a) irrevocably and unconditionally consents and submits to the exclusive jurisdiction and venue of the Court of Chancery of the State of Delaware in
and for New Castle County, Delaware, (b) agrees that it will not attempt to deny or defeat such jurisdiction by motion or other request for leave from such court, and (c) agrees that it will not bring any such action in any court other
than the Court of Chancery for the State of Delaware in and for New Castle County, Delaware, or, if (and only if) such court finds it lacks subject matter jurisdiction, the federal court of the United States of America sitting in the State of
Delaware, and appellate courts thereof, or, if (and only if) each of such Court of Chancery for the State of Delaware and such federal court finds it lacks subject matter jurisdiction, any state court within the State of Delaware. Service of
process, summons, notice or document to any party’s address and in the manner set forth in Section 9.4 shall be effective service of process for any such action. Each party hereto irrevocably designates C.T.
Corporation as its agent and attorney-in-fact for the acceptance of service of process and making an appearance on its behalf in any such claim or proceeding and for the
taking of all such acts as may be necessary or appropriate in order to confer jurisdiction over it before the aforementioned courts and each party hereto stipulates that such consent and appointment is irrevocable and coupled with an interest. 

9.6    Interpretation. The headings herein are for reference purposes only and shall not affect in any way the
meaning or interpretation of this Agreement. The parties hereto have participated jointly in the negotiation and drafting of this Agreement and, in the event that an ambiguity or question of intent or interpretation arises, this Agreement shall be
construed as jointly drafted by the parties hereto and no presumption or burden of proof shall arise favoring or disfavoring any party by virtue of the authorship of any provision of this Agreement. 

  
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 9.7    Entire Agreement; No Other Representations. This Agreement, the
DT Support Agreement and the Business Combination Agreement constitute the entire agreement, and supersede all other prior and contemporaneous agreements, understandings, undertakings, arrangements, representations and warranties, both written and
oral, among the parties with respect to the subject matter hereof. 
 9.8    No Third-Party Beneficiaries. Except
as provided in Section 4.7, this Agreement is not intended to confer upon any Person other than the parties hereto any rights or remedies hereunder. 

9.9    Severability. If any term or other provision of this Agreement is invalid, illegal or incapable of being
enforced by any rule of law or public policy, all other conditions and provisions of this Agreement shall nevertheless remain in full force and effect. Upon a determination that any term or other provision is invalid, illegal or incapable of being
enforced, the parties hereto shall negotiate in good faith to modify this Agreement so as to effect the original intent of the parties as closely as possible to the fullest extent permitted by applicable Law in an acceptable manner to the end that
the transactions contemplated hereby are fulfilled to the extent possible. 
 9.10    Counterparts. This
Agreement may be executed in two or more counterparts, all of which shall be considered one and the same agreement and shall become effective when one or more counterparts have been signed by each of the parties hereto and delivered to the other
parties. 
 9.11    Affiliated Entities. To the extent that any Controlled Affiliate of DT is a DT Stockholder,
DT shall cause such Controlled Affiliate to comply with all obligations under this Agreement applicable to the DT Stockholder, and in furtherance of the foregoing, if any Controlled Affiliate of DT becomes a Beneficial Owner of Shares on or after
the date hereof, (i) DT shall give each of Sprint and SoftBank written notice thereof in advance of such Controlled Affiliate becoming a Beneficial Owner and (ii) such Controlled Affiliate shall, and DT shall cause such Controlled
Affiliate to, promptly (and in advance of such Controlled Affiliate becoming a Beneficial Owner, if reasonably practicable) execute a joinder to this Agreement substantially in the form of Annex I, and to execute any and all documents or
instruments and take such other actions required, or otherwise reasonably requested by Sprint or SoftBank, to ensure that such Controlled Affiliate is subject to the obligations under this Agreement applicable to the DT Stockholder and that such
Shares are subject to this Agreement (provided, that any failure to execute such documents or instruments or take such other actions shall not affect such obligations hereunder). 

[Signature page follows] 

  
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 IN WITNESS WHEREOF, the parties have caused this Agreement to be duly executed as of the date
first above written. 
  

			
	DEUTSCHE TELEKOM HOLDING B.V.
		
	By:	 	 /s/ Raphael Kübler

	Name:	 	Raphael Kübler
	Title:	 	Managing Director
		
	By:	 	 /s/ Roman Zitz

	Name:	 	Roman Zitz
	Title:	 	Managing Director
	
	DEUTSCHE TELEKOM AG
		
	By:	 	 /s/ Timotheus Höttges

	Name:	 	Timotheus Höttges
	Title:	 	Member of the Management Board, CEO
		
	By:	 	 /s/ Thomas Dannenfelt

	Name:	 	Thomas Dannenfelt
	Title:	 	Member of the Management Board


 [Signature Page to Support Agreement] 







 
			
	SOFTBANK GROUP CORP.
		
	By:	 	 /s/ Yoshimitsu Goto

	Name:	 	Yoshimitsu Goto
	Title:	 	Senior Executive Corporate Officer, CFO
	
	SPRINT CORPORATION
		
	By:	 	 /s/ Marcelo Claure

	Name:	 	Marcelo Claure
	Title:	 	Chief Executive Officer


 [Signature Page to Support Agreement] 







 Exhibit A 

FORM OF WRITTEN CONSENT OF STOCKHOLDER 

IN LIEU OF A MEETING 

[●], 201[●] 
 The
undersigned, being the stockholder of T-Mobile US, Inc., a Delaware corporation (the “Company”), holding a majority of the outstanding shares of common stock, par value $0.00001 per share, of
the Company (the “Stockholder”), acting by written consent in lieu of a special meeting, pursuant to the provisions of Section 228 of the General Corporation Law of the State of Delaware (“DGCL”) and Article
VII(B) of the fourth amended and restated certificate of incorporation of the Company (the “Original Charter”), hereby consents in writing to the adoption without a meeting of the following resolutions and to the taking of each of
the actions contemplated thereby as of the date first written above: 
 WHEREAS, the Board of Directors of the Company (the
“Board”) and a committee of the Board consisting solely of independent directors of the Company have determined that it is advisable and fair to, and in the best interests of, the Company and all of its stockholders for the Company
to enter into, and have authorized the execution and delivery of, a Business Combination Agreement (the “Business Combination Agreement”), dated April 29, 2018, by and among the Company, Huron Merger Sub LLC, a Delaware limited
liability company and a wholly owned subsidiary of the Company (“Merger Company”), Superior Merger Sub Corporation, a Delaware corporation and a wholly owned subsidiary of Merger Company (“Merger Sub”), Sprint
Corporation, a Delaware corporation (“Sprint”), Starburst I, Inc., a Delaware corporation (“Starburst”), Galaxy Investment Holdings, Inc. (“Galaxy”), a Delaware corporation, and for the limited
purposes of the covenants and representations and warranties set forth therein that are expressly obligations of such persons, Deutsche Telekom AG, an Aktiengesellschaft organized and existing under the laws of the Federal Republic of Germany
(“DT”), Deutsche Telekom Holding B.V., a besloten vennootschap met beperkte aansprakelijkheid organized and existing under the laws of the Netherlands and SoftBank Group Corp., a Japanese kabushiki kaisha
(“SoftBank”); 
 WHEREAS, the Business Combination Agreement provides for, among other things, the merger of Merger Sub
with and into Sprint (the “Merger”), with Sprint continuing as the surviving corporation and a wholly owned subsidiary of Merger Company, with each share of common stock, par value $0.01 per share, of Sprint (“Sprint Common
Stock”) (other than certain treasury and other similar internally held shares) converting into the right to receive 0.10256 validly issued, fully paid and nonassessable shares of common stock, par value $0.00001 per share, of the Company
(“Company Common Stock”), (ii) the issuance of shares of Company Common Stock to the holders of shares of shares of Sprint Common Stock as of immediately prior to the Effective Time (as defined in the Business Combination Agreement)
in accordance with the terms of the Business Combination Agreement and, if the SoftBank US Mergers (as defined in the Business Combination Agreement) are consummated, shares of common stock, par value $0.01 per share, of Starburst and shares of
common stock, par value $0.01 per share, of 







 
Galaxy as of immediately prior to the SoftBank US Mergers Effective Time (as defined in the Business Combination Agreement) in accordance with the terms of the Business Combination Agreement (the
“Company Share Issuance”) and (iii) the amendment and restatement of the Original Charter in its entirety in the form attached as Annex I hereto at the Effective Time (as defined in the Business Combination Agreement)
(the “Company Charter Amendment”); and 
 WHEREAS, in accordance with the resolutions of the Board approving the Business
Combination Agreement, the Company Share Issuance and the Company Charter Amendment, the Company has executed and delivered the Business Combination Agreement and submitted the Company Share Issuance and the Company Charter Amendment to the
stockholders of the Company for their adoption and approval. 
 Approval of Business Combination Agreement 

NOW, THEREFORE, BE IT RESOLVED, that the Company Share Issuance and the Company Charter Amendment be, and they hereby are, adopted, ratified,
approved and authorized in all respects by the Stockholder, and that the Company be, and hereby is, authorized, directed and empowered to (i) perform its obligations under the Business Combination Agreement and (ii) enter into and perform
its obligations under each other agreement, instrument or certificate required or permitted to be entered into by the Company under the terms of the Business Combination Agreement; 

FURTHER RESOLVED, that any of the officers of the Company be, and each hereby is, authorized, directed and empowered, acting on behalf of the
Company, to execute and deliver any certificates, documents, agreements and instruments that any officer or officers executing such documents may, in the exercise of such officer’s or officers’ discretion, deem appropriate, advisable and
in the best interests of the Company pursuant to the foregoing resolution, together with such amendments and modifications thereof as shall be made therein with the approval of such officer or officers, the execution of which shall be conclusive
evidence of such approval; 
 FURTHER RESOLVED, that the officers of the Company be, and each of them hereby is, authorized and directed, on
behalf and in the name of the Company, to cause to be prepared, executed and filed with the appropriate foreign, federal, state or local governmental authorities or instrumentalities such registrations, declarations or other filings as any such
officer may deem necessary or desirable or as may be required by such governmental authorities or instrumentalities in connection with the transactions contemplated by the Business Combination Agreement; 

FURTHER RESOLVED, that the officers of the Company be, and each of them hereby is, authorized and directed, on behalf and in the name of the
Company, to do or cause to be done any and all such further acts and things and to execute and deliver any and all such additional agreements, certificates, documents and instruments as any such officer may deem necessary or appropriate in
connection with the transactions contemplated by the Business Combination Agreement; 

  
 A-2 








 FURTHER RESOLVED, that the Board be, and hereby is, authorized and empowered to amend the
Business Combination Agreement and take any other action with respect to the Business Combination Agreement permitted under Section 251(d) of the DGCL, as the Board may, in the exercise of its discretion, deem advisable, appropriate and in the
best interests of the Company and its stockholders; and 
 FURTHER RESOLVED, that any and all acts heretofore done, and any and all
documents, instruments and certificates heretofore executed and delivered, in the name and on behalf of the Company, in connection with the transactions contemplated by the Business Combination Agreement are hereby ratified and approved in all
respects. 
 The undersigned hereby waives compliance with any and all notice requirements imposed by the DGCL or other applicable law. This
consent may be executed in counterparts and all so executed shall constitute one consent, notwithstanding that all such signatories are not signatories to the original or the same counterparty. 

When executed by the Stockholder, this Consent shall be delivered to the Company in accordance with Section 2 of the Support Agreement,
dated as of April 29, 2018, by and among DT, the DT Stockholder, Sprint and SoftBank. 
 [Signature Page Follows]


  
 A-3 








 IN WITNESS WHEREOF, the Stockholder has executed this written consent as of the
date first written above. 
  

			
	DEUTSCHE TELEKOM HOLDING B.V. 
		
	By:	 	          

	Name:	 	
	Title:	 	









 Annex I 

Form of Joinder 
 The
undersigned is executing and delivering this joinder agreement (this “Joinder”) pursuant to that certain Support Agreement, dated as of April 29, 2018 (as amended, restated, supplemented or otherwise modified in accordance with
the terms thereof, the “DT Support Agreement”) by and among Deutsche Telekom AG, an Aktiengesellschaft organized and existing under the Laws of the Federal Republic of Germany (“DT”), Deutsche Telekom Holding
B.V., a besloten vennootschap met beperkte aansprakelijkheid organized and existing under the laws of the Netherlands and an indirect wholly owned subsidiary of DT (the “DT Stockholder”), Sprint Corporation, a Delaware
corporation (“Sprint”), and SoftBank Group Corp., a Japanese kabushiki kaisha (“SoftBank”). Capitalized terms used but not defined in this Joinder shall have the respective meanings ascribed to such terms in
the DT Support Agreement. 
 By executing and delivering this Joinder to the DT Support Agreement, the undersigned hereby adopts and
approves the DT Support Agreement and agrees, effective commencing on the date hereof and as a condition to the undersigned becoming a Beneficial Owner of Shares, to become a party to, and to be bound by and comply with the provisions of, the DT
Support Agreement applicable to the DT Stockholder in the same manner as if the undersigned were an original signatory to the DT Support Agreement. 

The undersigned hereby represents and warrants that it is a Controlled Affiliate of DT. 

Section 9 of the DT Support Agreement is hereby incorporated herein by reference, mutatis mutandis. 

[Remainder of page intentionally left blank] 







 Accordingly, the undersigned has executed and delivered this Joinder as of the
     day of             ,         . 
  


			
	[TRANSFEREE]
		
	By:	 	          

	Name:	 	
	Title:	 	


 
			
	
	Notice Information
		
	Address:	 	
	Telephone:	 	
	Email: