INDEMNIFICATION AGREEMENT

Exhibit 10.4

INDEMNIFICATION AGREEMENT

This INDEMNIFICATION AGREEMENT (this “Agreement”) is made and entered into this 30^th day of January, 2013 (the “Effective Date”) by and between Starburst II, Inc., a Delaware corporation (the “Company”), SOFTBANK CORP., a Japanese kabushiki kaisha (“SoftBank”) (limited solely for purposes of Section 12 of this Agreement), and Masayoshi Son (the “Indemnitee”).

WHEREAS, the Company believes it is essential to retain and attract qualified directors and officers;

WHEREAS, the Indemnitee is expected to become a director and officer of the Company and will be identified as a prospective director in the Company’s Registration Statement on form S-4;

WHEREAS, both the Company and the Indemnitee recognize the increased risk of litigation and other claims being asserted against directors and officers of public companies;

WHEREAS, the Company’s Bylaws (the “Bylaws”) require the Company to indemnify and advance expenses to its directors and officers to the extent permitted by the DGCL (as hereinafter defined);

WHEREAS, the Indemnitee intends to serve as a director and officer of the Company in part in reliance on the indemnification provisions of the Bylaws; and

WHEREAS, in recognition of the Indemnitee’s need for (a) substantial protection against personal liability based on the Indemnitee’s reliance on the Bylaws and the rights afforded under this Agreement, and (b) an inducement to provide effective services to the Company as a director and officer thereof, the Company wishes to provide for the indemnification of the Indemnitee and to advance expenses to the Indemnitee to the fullest extent permitted by law and as set forth in this Agreement, and, to the extent insurance is maintained by the Company, to provide for the coverage of the Indemnitee under the Company’s directors’ and officers’ liability insurance policies.

NOW, THEREFORE, in consideration of the premises contained herein and of the Indemnitee serving the Company directly or, at its request, with another enterprise, and intending to be legally bound hereby, the parties hereto agree as follows:

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1. Certain Definitions.

(a) “Contemplated Merger” shall mean the merger contemplated by that certain Agreement and Plan of Merger, as amended from time to time, entered into as of October 15, 2012, by and among the Company, SoftBank, Starburst I, Inc., a Delaware corporation and a direct wholly owned subsidiary of SoftBank, Starburst III, Inc., a Kansas corporation and a direct wholly owned subsidiary of the Company, and Sprint Nextel Corporation, a Kansas corporation.

(b) “DGCL” shall mean the General Corporation Law of the State of Delaware, as the same exists or may hereafter be amended or interpreted; provided, however, that in the case of any such amendment or interpretation, only to the extent that such amendment or interpretation permits the Company to provide broader rights to indemnification and advancement of expenses than were permitted prior thereto.

(c) “Expense” shall mean attorneys’ fees and all other costs, expenses and obligations paid or incurred in connection with investigating, defending, being a witness in or participating in (including on appeal), or preparing for any of the foregoing, any Proceeding relating to or arising out of any Indemnifiable Event.

(d) “Indemnifiable Event” shall mean any event or occurrence that takes place either prior to, on or after the execution of this Agreement, related to or arising out of the fact that the Indemnitee is or was a director or officer of the Company or its subsidiaries, or while a director or officer is or was serving at the request of the Company as a director, officer, employee, or agent of another corporation or of a partnership, joint venture, trust or other enterprise, including service with respect to employee benefit plans, or related to or arising out of anything done or not done by the Indemnitee in any such capacity.

(e) “Proceeding” shall mean any threatened, pending or completed action, suit, investigation or proceeding, and any appeal thereof, whether civil, criminal, administrative, arbitrative, investigative or otherwise and/or any inquiry or investigation, whether formal or informal, conducted by the Company or any other party, that the Indemnitee in good faith believes might lead to the institution of any such action.

2. Indemnification. In the event the Indemnitee was or is a party to, or is threatened to be made a party to, or is involved (as a party, witness, or otherwise) in any Proceeding by reason of (or arising in part out of) an Indemnifiable Event, whether the basis of the Proceeding is the Indemnitee’s alleged action in an official capacity as a director or officer of the Company or any of its subsidiaries or in any other capacity while serving as a director or officer of the Company or any of its subsidiaries, the Company shall indemnify the Indemnitee to the fullest extent permitted by the DGCL against any and all Expenses, liability, and loss (including judgments, fines, ERISA excise taxes or penalties, and amounts paid or to be paid in settlement, and any interest, assessments, or other charges imposed thereon, and any federal, state, local, or foreign taxes imposed on any director or officer as a result of the actual or deemed receipt of any payments under this Agreement) (collectively, “Liabilities”) reasonably incurred or suffered by such person in connection with such Proceeding. The Company shall provide indemnification pursuant to this Section 2 as soon as practicable, but in no event later than 20 calendar days after it receives written demand from the Indemnitee.

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3. Advancement of Expenses. The Company shall advance Expenses to the Indemnitee within 20 calendar days of such request (an “Expense Advance”); provided, however, that if required by applicable corporate laws such Expenses shall be advanced only upon delivery to the Company of an undertaking by or on behalf of the Indemnitee to repay such amount if it is ultimately determined that the Indemnitee is not entitled to be indemnified by the Company; and provided further, that the Company shall make such advances only to the extent permitted by law. Expenses incurred by the Indemnitee while not acting in his/her capacity as a director or officer of the Company or any subsidiary thereof, including service with respect to employee benefit plans, may be advanced upon such terms and conditions as the Board, in its sole discretion, deems appropriate.

4. Partial Indemnity. If the Indemnitee is entitled under any provision of this Agreement to indemnification by the Company for some or a portion of the Expenses and Liabilities, but not, however, for all of the total amount thereof, the Company shall nevertheless indemnify the Indemnitee for the portion thereof to which the Indemnitee is entitled. Moreover, notwithstanding any other provision of this Agreement, to the extent that the Indemnitee has been successful on the merits or otherwise in defense of any or all Proceedings relating in whole or in part to an Indemnifiable Event or in defense of any issue or matter therein, including dismissal without prejudice, the Indemnitee shall be indemnified against all Expenses incurred in connection therewith.

5. Non-exclusivity. The rights of the Indemnitee hereunder shall be in addition to any other rights the Indemnitee may have under any statute, provision of the Company’s Certificate of Incorporation or Bylaws, vote of stockholders or disinterested directors or otherwise, both as to action in an official capacity and as to action in another capacity while holding such office. To the extent that a change in the DGCL permits greater indemnification by agreement than would be afforded currently under the Company’s Certificate of Incorporation and Bylaws and this Agreement, it is the intent of the parties hereto that the Indemnitee shall enjoy by this Agreement the greater benefits so afforded by such change.

6. Liability Insurance. To the extent the Company maintains an insurance policy or policies providing directors’ and officers’ liability insurance, the Indemnitee shall be covered by such policy or policies, in accordance with its or their terms, to the maximum extent of the coverage available for any director or officer of the Company or any of its subsidiaries, depending on the Indemnitee’s position therewith, and the Company shall use commercially reasonable efforts to maintain such coverage in effect in accordance with its terms. In all policies providing such insurance, the Indemnitee shall be named as an insured in such a manner as to provide the Indemnitee the same rights and benefits as are accorded to the most favorably insured of the Company’s officers and directors. The Company shall give prompt notice of the commencement of any Proceeding to the insurers in accordance with the procedures set forth in the respective policies and shall thereafter take all necessary actions to cause such insurers to pay, on behalf of the Indemnitee, all amounts payable as a result of such Proceeding in accordance with the terms of such policies.

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7. Settlement of Claims. The Company shall not be liable to indemnify the Indemnitee under this Agreement (a) for any amounts paid in settlement of any action or claim effected without the Company’s written consent, which consent shall not be unreasonably withheld; or (b) for any judicial award if the Company was not given a reasonable and timely opportunity, at its expense, to participate in the defense of such action.

8. Presumptions. Upon submitting a written request for indemnification, the Indemnitee shall be presumed to be entitled to indemnification hereunder and the Company shall have the burden of proof in making any determination contrary to such presumption. For purposes of this Agreement, to the fullest extent permitted by law, the termination of any Proceeding, action, suit or claim, by judgment, order, settlement (whether with or without court approval) or conviction, or upon a plea of nolo contendere, or its equivalent, shall not (a) create a presumption that the Indemnitee did not meet any particular standard of conduct or have any particular belief or that a court has determined that indemnification is not permitted by applicable law or (b) otherwise adversely affect the rights of the Indemnitee to indemnification except as may be provided herein.

9. Period of Limitations. No legal action shall be brought and no cause of action shall be asserted with respect to any dispute arising out of this Agreement by or on behalf of the Company or any affiliate of the Company against the Indemnitee, the Indemnitee’s spouse, heirs, executors or personal or legal representatives after the expiration of two years from the date of accrual of such cause of action, or such longer period as may be required by state law under the circumstances, and any claim or cause of action of the Company or its affiliate shall be extinguished and deemed released unless asserted by the timely filing of a legal action within such period; provided, however, that if any shorter period of limitations is otherwise applicable to any such cause of action, such shorter period shall govern.

10. Amendment of this Agreement. No supplement, modification or amendment of this Agreement shall be binding unless executed in writing by each of the parties hereto. No waiver of any of the provisions of this Agreement shall be deemed or shall constitute a waiver of any other provisions hereof (whether or not similar), nor shall such waiver constitute a continuing waiver. Except as specifically provided herein, no failure to exercise or any delay in exercising any right or remedy hereunder shall constitute a waiver thereof.

11. Primacy of Indemnification. Notwithstanding that the Indemnitee may have certain rights to indemnification, advancement of expenses and/or insurance provided by other persons (collectively, the “Other Indemnitors”), the Company: (a) shall be the indemnitor of first resort (i.e., its obligations to the Indemnitee are primary and any obligation of the Other Indemnitors to advance expenses or to provide indemnification for the same expenses or liabilities incurred by the Indemnitee are secondary); and (b) shall be required to advance the full amount of expenses incurred by the Indemnitee and shall be liable for the full amount of all Expenses, without regard to any rights the Indemnitee may have against any of the Other Indemnitors. No advancement or payment by the Other Indemnitors on behalf of the Indemnitee with respect to any claim for which the Indemnitee has sought indemnification from the Company shall affect the immediately preceding sentence, and the Other Indemnitors shall have a right of contribution and/or be subrogated to the extent of such advancement or payment to all of the rights of recovery of the Indemnitee against the Company. The Company and the Indemnitee agree that the Other Indemnitors are express third party beneficiaries of the terms of this Section 11.

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12. Obligations of SoftBank. Until the closing of the Contemplated Merger, SoftBank will, to the fullest extent permitted under applicable law: (i) cause the Company to take all such actions as are required pursuant to the terms of this Agreement; and (ii) advance to the Company for the Company to pay or to advance, and otherwise cause the Company to pay or advance, all amounts that the Company is obligated (or has agreed) to pay or advance to, or for the benefit of, the Indemnitee, pursuant to the terms of this Agreement.

13. Subrogation; Attorneys’ Fees. In the event of payment under this Agreement, the Company shall be subrogated to the extent of such payment to all of the rights of recovery of the Indemnitee (other than against the Other Indemnitors), who shall execute all papers required and shall do everything that may be necessary to secure such rights, including the execution of such documents necessary to enable the Company effectively to bring suit to enforce such rights. If any proceeding is commenced related to or arising out of this Agreement, any prevailing party shall be entitled to have their Expenses in connection with such proceeding paid by the non-prevailing party.

14. No Duplication of Payments. The Company shall not be liable under this Agreement to make any payment in connection with any claim made against the Indemnitee to the extent the Indemnitee has otherwise actually received payment (under any insurance policy, governing or organizational document, vote, agreement or otherwise) of the amounts otherwise indemnifiable hereunder.

15. Binding Effect. This Agreement shall be binding upon and inure to the benefit of and be enforceable by the parties hereto and their respective successors, assigns, including any direct or indirect successor by purchase, merger, consolidation or otherwise to all or substantially all of the business and/or assets of the Company, spouses, heirs, and personal and legal representatives. The Company shall require and cause any successor (whether direct or indirect by purchase, merger, consolidation or otherwise) to all, substantially all, or a substantial part, of the business and/or assets of the Company, by written agreement in form and substance satisfactory to the Indemnitee, expressly to assume and agree to perform this Agreement in the same manner and to the same extent that the Company would be required to perform if no such succession had taken place. This Agreement shall continue in effect regardless of whether the Indemnitee continues to serve as a director or officer of the Company or of any other enterprise at the Company’s request.

16. Severability. The provisions of this Agreement shall be severable in the event that any of the provisions hereof (including any provision within a single section, paragraph or sentence) is held by a court of competent jurisdiction to be invalid, void or otherwise unenforceable, and the remaining provisions shall remain enforceable to the fullest extent permitted by law. Furthermore, to the fullest extent possible, the provisions of this Agreement (including, without limitation, each portion of this Agreement containing any provision held to be invalid, void or otherwise unenforceable, that is not itself invalid, void or unenforceable) shall be construed so as to give effect to the intent manifested by the provision held invalid, illegal or unenforceable.

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17. Governing Law. This Agreement shall be governed by and construed and enforced in accordance with the laws of the State of Delaware applicable to contracts made and to be performed in such State without giving effect to the principles of conflicts of laws.

18. Counterparts. This Agreement may be executed in one or more counterparts, each of which shall be deemed an original, but all of which together shall constitute one and the same instrument.

19. Headings. The headings of the sections of this Agreement are inserted for convenience only and shall not be deemed to constitute part of this Agreement or to affect the construction thereof.

20. Notices. All notices, demands, and other communications required or permitted hereunder shall be made in writing and shall be deemed to have been duly given if delivered by hand, against receipt, or mailed, postage prepaid, certified or registered mail, return receipt requested, and addressed to the Company at:

Notice of change of address shall be effective only when done in accordance with this Section. All notices complying with this Section shall be deemed to have been received on the date of delivery or on the third business day after mailing.

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IN WITNESS WHEREOF, the parties hereto have duly executed and delivered this Agreement as of the date first set forth above.

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