SUMMARY OF THE PROXY STATEMENT-PROSPECTUS

This summary highlights information contained elsewhere in this proxy statement-prospectus and may not contain all the information that is important to you with respect to the SoftBank Merger and the other matters being considered at the special stockholders’ meeting. We urge you to read the remainder of this proxy statement-prospectus carefully, including the attached Annexes, and the other documents incorporated by reference herein. See also the section entitled “Where You Can Find More Information.” We have included page references in this summary to direct you to more complete descriptions of the topics presented below.

The Companies (see pages 74 and 75)

Sprint

Sprint (together with its consolidated subsidiaries) is a communications company offering a comprehensive range of wireless and wireline communications products and services that are designed to meet the needs of individual consumers, businesses, government subscribers and resellers. Sprint’s operations are organized to meet the needs of its targeted subscriber groups through focused communications solutions that incorporate the capabilities of its wireless and wireline services. Sprint is the third largest wireless communications company in the United States based on wireless revenue, one of the largest providers of wireline long distance services, and one of the largest carriers of Internet traffic in the nation. Sprint’s services are provided through its ownership of extensive wireless networks, an all-digital global long distance network and a Tier 1 Internet backbone.

Sprint’s principal offices are located at 6200 Sprint Parkway, Overland Park, Kansas 66251 and its telephone number is (855) 848-3280. Sprint common stock is listed on the NYSE, trading under the symbol “S.”

For further information see “The Parties to the SoftBank Merger” beginning on page 74.

Parent, Merger Sub and HoldCo

Parent and Merger Sub are wholly owned subsidiaries of SoftBank, formed by SoftBank specifically for the transactions contemplated by the Merger Agreement and the Bond Purchase Agreement. To date, neither of these entities has conducted any activities other than those incident to their formation, the matters contemplated by the Merger Agreement and the Bond Purchase Agreement (including the purchase by Parent of the $3.1 billion convertible bond issued by Sprint (the “Bond”)) and the preparation of this proxy statement-prospectus. Pursuant to the Merger Agreement, Merger Sub will merge with and into Sprint, with Sprint surviving the SoftBank Merger as a wholly owned subsidiary of Parent. Parent is a “business combination related shell company” under applicable provisions of the Securities Act that was formed by SoftBank for the sole purpose of completing the transactions contemplated by the Merger Agreement and the Bond Purchase Agreement. As of the consummation of the SoftBank Merger, New Sprint’s assets will consist of 100% of the outstanding common stock of Sprint and cash, $4.9 billion of which is to be contributed to New Sprint at or before the effective time of the SoftBank Merger by SoftBank. For further information, see “—The Structure of the SoftBank Merger” beginning on page 5 and “The Merger Agreement—Structure and Effect of the SoftBank Merger” beginning on page 136.

At the effective time of the SoftBank Merger, New Sprint will be renamed “Sprint Corporation,” and Sprint as the operating subsidiary after the SoftBank Merger will be renamed “Sprint Communications, Inc.”

After the SoftBank Merger is completed, New Sprint will be a “controlled company” under the rules of the NYSE and will qualify for certain exemptions relating to corporate governance under the NYSE listing standards. See “Control and Management of New Sprint after the SoftBank Merger” beginning on page 177.

HoldCo is a wholly owned subsidiary of SoftBank, formed by SoftBank specifically to hold securities of Parent in connection with the transactions contemplated by the Merger Agreement.

The principal executive offices of Parent and Merger Sub are located at 11501 Outlook Street 4th Floor, Overland Park, Kansas 66211 and the principal executive offices of HoldCo are located at 1 Circle Star Way, San Carlos, California 94070, and their telephone number is (617) 928-9300.

For further information see “The Parties to the SoftBank Merger” beginning on page 74.

SoftBank

SoftBank was established in 1981. It is currently engaged in various businesses in the information industry, including mobile communications (through its subsidiary, SoftBank Mobile Corp.), broadband services (through its subsidiary, SoftBank BB Corp.), fixed-line telecommunications (through its subsidiary, SoftBank Telecom Corp.) and portal services (through its consolidated subsidiary, Yahoo Japan Corporation). As of the end of its fiscal year ended March 31, 2012, SoftBank had 133 consolidated subsidiaries in total and had investments in 74 companies that it accounted for on an equity-method basis. By generating synergies among SoftBank’s portfolio of companies, as well as working with companies around the world that share its vision, SoftBank’s goal is to become the world leader in mobile Internet while creating new value for customers and using the Information Revolution to contribute to the wellbeing of people and society.

As of March 31, 2013, SoftBank was Japan’s second largest mobile communications company in terms of mobile subscribers, with over 41.9 million subscribers representing a 29.7% total market share in Japan, including 32.5 million subscribers from SoftBank Mobile Corp., 4.3 million subscribers from eAccess Ltd. (“eAccess”) and 5.1 million PHS subscribers from WILLCOM, Inc. (“Willcom”). eAccess is Japan’s fourth largest wireless company, and SoftBank holds all of eAccess’ Class A shares and 33.29% of eAccess’ Class B shares. The rights of the holders of each class are the same, except that holders of eAccess’ Class A shares have no voting rights. Accordingly, SoftBank has 33.29% voting control of eAccess and treated eAccess as an equity method affiliate under accounting principles generally accepted in Japan. However, from the fiscal quarter ending June 30, 2013, SoftBank will report its financial results under International Financial Reporting Standards (“IFRS”). Under IFRS, SoftBank will treat eAccess as a consolidated subsidiary. On March 12, 2010, SoftBank entered into a framework agreement to assist with the reorganization of Willcom under the Japanese Corporate Reorganization Act. SoftBank subsequently became Willcom’s sponsor in connection with Willcom’s reorganization, pursuant to a sponsor agreement entered into on August 2, 2010. Under the reorganization plan, SoftBank owns 100% of Willcom’s shares but does not have effective control over Willcom since Willcom remains under court administration. Accordingly, SoftBank does not treat Willcom as a subsidiary or consider it an equity method affiliate.

SoftBank’s consolidated net sales increased 6.6% year-on-year to ¥3.2 trillion, or approximately $34.0 billion, operating income increased 7.3% to ¥675.2 billion, or approximately $7.2 billion, and net income rose 65.4% to ¥313.7 billion, or approximately $3.3 billion during its fiscal year ended March 31, 2012. U.S. dollar equivalents expressed in this paragraph are based on the exchange rate of 94.2 JPY per U.S. dollar as reported by the U.S. Federal Reserve as of March 31, 2013 solely for informational purposes.

SoftBank’s ordinary shares are traded on the Tokyo Stock Exchange under the code “9984.” SoftBank (together with its consolidated subsidiaries) had over 22,000 employees as of the end of its fiscal year ended March 31, 2012.

Sprint stockholders and other Sprint equityholders will not be receiving any interest in SoftBank or SoftBank’s ordinary shares in connection with the SoftBank Merger or the other transactions described herein.

SoftBank’s principal executive offices are located at 1-9-1 Higashi-Shimbashi, Minato-ku, Tokyo 105-7303, Japan, and its telephone number is +81.3.6889.2000.

For further information see “The Parties to the SoftBank Merger” beginning on page 74.

Financing

SoftBank has entered into a credit agreement dated December 18, 2012 (the “Credit Agreement”) with Mizuho Corporate Bank, Ltd., Sumitomo Mitsui Banking Corporation, The Bank of Tokyo-Mitsubishi UFJ, Ltd. and Deutsche Bank AG, Tokyo Branch pursuant to which such banks have agreed to provide to SoftBank secured short-term debt financing under two facilities for the purpose of consummating the SoftBank Merger and the other transactions contemplated by the Merger Agreement, subject to the satisfaction of certain conditions precedent. On December 21, 2012, these lenders provided SoftBank with a loan of ¥250 billion (approximately $2.65 billion) under the first of SoftBank’s short-term debt facilities. Under the second of SoftBank’s short-term debt facilities, these lenders are now committed to provide SoftBank, subject to the satisfaction of certain conditions precedent, a loan of up to ¥1.0349 trillion (approximately $11.0 billion). SoftBank reduced this commitment from ¥1.4 trillion in March 2013 (approximately $14.9 billion) upon its receipt of cash proceeds from a pair of bond issuances that SoftBank intends to apply towards the consideration payable at the closing of the SoftBank Merger. In order to protect against the devaluation of the Japanese yen to the U.S. dollar, SoftBank has hedged $20.1 billion of the consideration for the SoftBank Merger at an average exchange rate of JPY 82.2 per U.S. dollar. In addition, SoftBank raised $2.485 billion and €625 million (approximately $801 million) in gross proceeds from the issuance of senior U.S. dollar and euro notes, respectively, on April 23, 2013. U.S. dollar equivalents expressed in this paragraph are based on the exchange rate of 1.2816 euros per U.S. dollar or 94.2 JPY per U.S. dollar, as reported by the U.S. Federal Reserve on March 31, 2013, solely for informational purposes.

For further information, please see “The SoftBank Merger—Financing” beginning on page 119.

The Special Stockholders’ Meeting

The special stockholders’ meeting will be held on June 12, 2013, starting at 10:00 a.m., local time, at Ritz Charles, 9000 W. 137^th Street, Overland Park, Kansas 66221.

Sprint stockholders will be asked to vote on the following proposals:

Recommendation of the Sprint Board of Directors

After careful consideration, the Sprint board of directors has determined that the SoftBank Merger is in the best interests of Sprint and its stockholders and recommends that holders of Sprint common stock vote “FOR” the Merger Proposal, “FOR” the Merger-Related Compensation Proposal and “FOR” the Adjournment Proposal.

For a more complete description of Sprint’s reasons for the SoftBank Merger and the recommendation of the Sprint board of directors, see “The SoftBank Merger—Recommendation of the Sprint Board of Directors; Sprint’s Reasons for the SoftBank Merger” beginning on page 93. For a description of the merger-related Sprint executive compensation arrangements, see “The SoftBank Merger—Advisory Vote Regarding Merger-Related Executive Compensation (Say-on-Golden-Parachute)” beginning on page 130.

Opinions of Sprint’s Financial Advisors (see page 97)

In connection with the SoftBank Merger, the Sprint board of directors received a written opinion from each of Citigroup Global Markets, Inc. (“Citigroup”), Rothschild Inc. (“Rothschild”) and UBS Securities LLC (“UBS”), each dated October 15, 2012, to the effect that, as of such date, and based upon and subject to the assumptions made, procedures followed, matters and factors considered and limitations on the review undertaken set forth in their respective written opinions, the Aggregate Merger Consideration was fair, from a financial point of view, to the holders of Sprint common stock (other than Parent, Merger Sub and any other wholly owned subsidiary of Parent). On October 13, 2012 each of Citigroup, Rothschild and UBS had delivered to the Sprint board of directors its oral opinion to the same effect, which preceded the delivery of such written opinions of each financial advisor.

The full text of the written opinions of each of Citigroup, Rothschild and UBS, which set forth the assumptions made, procedures followed, matters and factors considered and limitations and qualifications on the review undertaken in connection with each such opinion, are attached as Annexes C, D and E, respectively, and are incorporated into this proxy statement-prospectus by reference. Holders of Sprint common stock are encouraged to read these opinions carefully in their entirety. These opinions were provided for the information of Sprint’s board of directors (in its capacity as such) in connection with its evaluation of the SoftBank Merger and did not address any aspects or implications of the SoftBank Merger or the other transactions contemplated by the Merger Agreement, as it existed on October 15, 2012, other than the fairness of the Aggregate Merger Consideration from a financial point of view, to the holders of Sprint common stock (other than New Sprint, Merger Sub and any other wholly owned subsidiary of New Sprint). Citigroup, Rothschild and UBS were not requested to consider, and their opinions did not address, the underlying business decision of Sprint to effect the Transactions (as defined below in “Summary of the Proxy Statement-Prospectus—Summary of the Warrant” on page 14), the relative merits of the Transactions as compared to any alternative business strategies that might exist for Sprint or the effect of any other transaction in which Sprint might engage. The respective opinions of Citigroup, Rothschild and UBS are not intended to be and do not constitute a recommendation to any stockholder as to how such stockholder should vote or act on any matters relating to the SoftBank Merger or otherwise, including whether any stockholder should elect to receive either the Cash Consideration or the Stock Consideration or make no election. With respect to the election of the Cash Consideration or the Stock Consideration, Citigroup, Rothschild and UBS expressed no opinions as to the related proration mechanisms, procedures and limitations in the Merger Agreement. The respective opinions of each of Citigroup, Rothschild and UBS were based solely upon the information available to these financial advisors as of October 15, 2012, the date on which their respective written opinions were rendered.

The opinions of each of Citigroup, Rothschild and UBS, and the financial scenario analyses, forecasts or projections upon which they may have been based, do not take into account or reflect, and the financial advisors were not asked to take into account or reflect, any changes or developments occurring subsequent to October 15, 2012. Since such date, certain material changes have occurred in Sprint’s current and anticipated business and financial condition, which changes include the proposed Clearwire Acquisition, various financings effected by Sprint including Sprint’s issuance of the Bond on October 15, 2012, the sale of $2.3 billion of other debt in the fourth quarter of 2012, and Sprint’s entry into a $3.0 billion five-year credit facility. Since October 15, 2012, Sprint has reported financial results for the quarter ended September 30, 2012 and the quarter and year ended December 31, 2012. Prior to the special stockholders’ meeting, Sprint will disclose certain additional results, including for the quarter ended March 31, 2013. Furthermore, in the course of its business planning, Sprint has adopted a capital budget for 2013 and developed various additional forward-looking financial models and business plans. Sprint has not, nor does it intend to, publicly disclosed such models or plans. In addition, on April 15, 2013, DISH publicly announced the DISH Proposal. All of the information described in this paragraph may have had the effect of superseding the information used by Citigroup, Rothschild and UBS in their analyses.

Additionally, Sprint has engaged each of Citigroup, Rothschild and UBS as a financial advisor in connection with Sprint’s evaluation of the DISH Proposal, any modification of the Transactions and any competing proposal from any third party.

For a more complete description of the opinions of Citigroup, Rothschild and UBS, see “The SoftBank Merger—Opinions of Sprint’s Financial Advisors—Citigroup, Rothschild and UBS” beginning on page 97. See also Annexes C, D and E to this proxy statement-prospectus.

The Structure of the SoftBank Merger

To accomplish the SoftBank Merger and the other transactions contemplated by the Merger Agreement, SoftBank formed HoldCo, Parent and Merger Sub (the “SoftBank Entities”), all of which are parties to the Merger Agreement. On October 22, 2012, Parent acquired the Bond from Sprint, and now beneficially owns approximately 16.4% of the outstanding shares of Sprint common stock (based on the number of shares of Sprint common stock into which the Bond may, under certain circumstances, be converted). The Bond is not convertible unless and until certain conditions are met. See “The Bond Purchase Agreement—Conversion of the Bond” beginning on page 136. At the time the SoftBank Merger is completed, Merger Sub will merge with and into Sprint, and Sprint will be the surviving corporation.

At the effective time of the SoftBank Merger, Sprint will become a wholly owned subsidiary of Parent. Parent, which is currently named “Starburst II, Inc.,” will be renamed “Sprint Corporation.”

Diagrams illustrating the SoftBank Merger and procedures are as follows:

Step 1—Initial Ownership Structure

Step 2—Merger

Step 3—Post-Merger Ownership Structure

Summary of the Material Terms of the SoftBank Merger (see page 136)

Closing and Effective Time of the SoftBank Merger. The Merger Agreement provides that the closing of the SoftBank Merger will take place on the latest of (a) three business days after the satisfaction or waiver (if permitted) of the conditions to the SoftBank Merger contained in the Merger Agreement, (b) on such later date (not later than seven business days after such date) as Parent may designate in order to obtain the Debt Financing, or (c) July 1, 2013, or on such other date or at such other time as Parent and Sprint may mutually designate. The effective time of the SoftBank Merger will be the time when the certificate of merger for the SoftBank Merger is filed with the Kansas Secretary of State, or at such later time as may be specified in such certificate of merger, in accordance with the relevant provisions of Kansas law.

Merger Consideration. In the SoftBank Merger, each Sprint stockholder is entitled to elect to receive, with respect to each share of Sprint common stock owned by it, subject to the proration and allocation rules described below, either $7.30 in cash or one share of New Sprint common stock. If a Sprint stockholder owns more than one share of Sprint common stock, that stockholder may elect to receive cash as to some of its shares of Sprint common stock and New Sprint common stock as to other shares of Sprint common stock, subject to such proration and allocation rules. Under the terms of the Merger Agreement, because the aggregate cash consideration that Sprint stockholders will be entitled to receive in the SoftBank Merger is fixed at $12.14 billion, at the effective time of the SoftBank Merger, an aggregate of approximately 1,663,013,699 of the outstanding shares of Sprint common stock (representing approximately 55.16% of the outstanding Sprint common stock calculated as of the meeting record date) will be entitled to be exchanged for $7.30 in cash per share of common stock (assuming there are no dissenting stockholders who perfect their appraisal rights). All remaining outstanding shares of Sprint common stock (representing approximately 44.84% of the outstanding Sprint common stock calculated as of the meeting record date) will be exchanged for New Sprint common stock on a one-for-one basis. Between the date of this proxy statement-prospectus and the effective time of the SoftBank Merger, the number of shares of Sprint common stock outstanding may vary, and accordingly the number of shares of Sprint common stock that will ultimately be exchanged for shares of New Sprint common stock in the SoftBank Merger will also vary. However, pursuant to the terms of the Merger Agreement, former Sprint stockholders and other former Sprint equityholders will not own in excess of 30% of the fully diluted equity of New Sprint as of the effective time of the SoftBank Merger. Please note that Sprint stockholders and other Sprint equityholders will not be receiving any interest in SoftBank or SoftBank’s ordinary shares in connection with the SoftBank Merger or the other transactions described herein.

Making the Cash/Stock Election. Each Sprint stockholder may make an election to receive cash, New Sprint common stock or, if electing for multiple shares, a combination of the two in exchange for the stockholder’s shares of Sprint common stock by delivering to Computershare, the exchange agent, a completed form of election together with the certificates representing their shares of Sprint common stock and any other required documentation specified in the form of election. Forms of election must be received by Computershare no later than the election deadline, which is expected to be 5:00 p.m., Eastern time, on the date that is five business days immediately preceding the effective time of the SoftBank Merger. Sprint will publicly announce the election deadline by press release at least five business days prior to the election deadline. SoftBank and Sprint anticipate that the SoftBank Merger will be completed in mid-2013, but no earlier than July 1, 2013.

Stockholders who hold their shares in “street name,” that is, with a broker, dealer, bank or other financial institution, and who wish to make an election will have to instruct their broker, dealer, bank or other financial institution that holds their shares to make an election on their behalf. Any share of Sprint common stock for which the record holder has not, prior to the election deadline, properly submitted a properly completed form of election to the exchange agent will be deemed to be a non-electing share. Accordingly, Sprint stockholders who fail to properly complete and return the form of election, together with any other required documentation specified in the form of election, prior to the election deadline will receive merger

consideration (consisting of cash, shares of New Sprint common stock or a combination of the two) that is identical to the merger consideration allocable to those stockholders that have elected to receive cash.

Once a holder of Sprint common stock has made a valid election with respect to shares, the stockholder will not be able to transfer such shares unless and until the stockholder has validly revoked such election. Any transferee of such shares must (if the election deadline has not occurred) make a new election with respect to such shares if such transferee does not wish the shares to be considered non-electing shares. If a Sprint stockholder makes a valid election (that has not been revoked prior to the election deadline) with respect to shares of Sprint common stock, after the election deadline the stockholder will not be able to revoke such election or transfer such shares prior to the effective time of the SoftBank Merger (except in certain circumstances when the expected effective time is delayed).

None of the SoftBank Entities, Sprint or the Sprint board of directors makes any recommendation about whether any Sprint stockholder should make an election to receive cash, New Sprint common stock or, if electing for multiple shares, a combination of the two, or no election. Each holder of shares of Sprint common stock must make his or her own decision about whether to make an election and, if so, what election to make.

For a more detailed description of the election procedures, see “Questions and Answers about the SoftBank Merger” beginning on page Q-1 and “The SoftBank Merger—Making the Cash/Stock Election” beginning on page 123.

Cash/Stock Proration and Allocation Rules. The proration rules applicable to the cash and stock elections to be made by Sprint stockholders have the potential to result in allocations of consideration that differ from the form of consideration elected (or deemed to have been elected). Depending on what type of consideration the other Sprint stockholders elect (or are deemed to have elected) to receive as consideration and the proration rules, a Sprint stockholder may not receive the preferred type of consideration with respect to all of the stockholder’s shares of Sprint common stock. The elections that a stockholder and other Sprint stockholders make (or are deemed to have made) regarding the receipt of cash or shares of New Sprint common stock in exchange for shares of Sprint common stock will determine the mix of consideration that a Sprint stockholder will receive in the SoftBank Merger.

If the cash proration rule applies (as a result of cash elections (collectively together with deemed cash elections) exceeding the available cash component of the merger consideration), a Sprint stockholder that elects (or is deemed to have elected) to receive cash for its shares of Sprint common stock will instead receive a combination of cash and shares of New Sprint common stock. If the stock proration rule applies (as a result of stock elections exceeding the available stock component of the merger consideration), a Sprint stockholder that elects to receive shares of New Sprint common stock for its shares of Sprint common stock will instead receive a combination of cash and shares of New Sprint common stock. As a result of the foregoing, you may not receive the form of consideration that you elect with respect to all of your shares of Sprint common stock.

For a more detailed description of these proration and allocation rules, including examples of how the proration rules would work under various scenarios, see “The SoftBank Merger—Cash/Stock Proration and Allocation Rules” beginning on page 126.

HoldCo Shares. In the SoftBank Merger, pursuant to the Merger Agreement and the organizational documents of New Sprint, all outstanding shares of New Sprint common stock held by HoldCo at the effective time of the SoftBank Merger will be automatically reclassified into a number of shares of New Sprint common stock representing 69.642% of the fully diluted equity of New Sprint (excluding shares of New Sprint common stock issuable upon exercise by HoldCo of a warrant to purchase up to 54,579,924 fully paid and nonassessable shares of New Sprint common stock (the “Warrant”), as discussed in “—Summary of the Warrant” beginning on

page 14) as of immediately following the effective time of the SoftBank Merger, and the former Sprint stockholders and other former equityholders of Sprint will hold, collectively, shares of New Sprint common stock and other equity securities of New Sprint collectively representing 30.358% of the fully diluted equity of New Sprint (excluding shares of New Sprint common stock issuable upon exercise by HoldCo of the Warrant) as of immediately following the effective time of the SoftBank Merger. In addition, the percentages described above assume that there will be no dissenting shares. The effect of dissenting shares, to the extent they would have otherwise received shares of New Sprint common stock in the SoftBank Merger had they not been dissenting shares, would be to increase the number of New Sprint’s outstanding shares held by both HoldCo and by other former Sprint stockholders who receive shares of New Sprint common stock in the SoftBank Merger such that the proportionate percentage of shares of New Sprint held by HoldCo and the former Sprint stockholders is the same.

Stock Options. At the effective time of the SoftBank Merger, each outstanding Sprint stock option will be converted into an option to purchase the number of shares of New Sprint common stock that is equal to (i) the number of shares of Sprint common stock that could have been purchased before the SoftBank Merger upon the exercise of such option multiplied by (ii) the “award exchange ratio” and rounded down to the nearest whole share. The award exchange ratio used to determine the number of shares of New Sprint common stock underlying stock options and RSUs is described under “The SoftBank Merger—Treatment of Stock Options, Restricted Stock Units, Performance Units, Employee Stock Purchase Plan and Deferred Compensation Plan Accounts” beginning on page 128. The exercise price per share of New Sprint common stock for the converted option will be equal to the exercise price per share of Sprint common stock subject to the option before the conversion divided by the award exchange ratio, with the result rounded up to the nearest whole cent. After the conversion, stock options shall nonetheless remain governed by the terms of the plans and agreements under which the options were granted, except that New Sprint’s board of directors or any committee of the board will succeed to the authority and responsibility of Sprint’s board of directors or a committee of the board with respect to each assumed option.

Restricted Stock Units. At the effective time of the SoftBank Merger, each outstanding Sprint RSU will be converted into a right to be issued the number of shares of New Sprint common stock that is equal to (i) the number of shares of Sprint common stock underlying such Sprint RSU before the SoftBank Merger multiplied by (ii) the award exchange ratio, with the result rounded down to the nearest whole share, in the aggregate on a per award basis. After the conversion, such RSUs shall nonetheless remain governed by the terms of the plans and agreements under which the RSUs were granted, except that (1) New Sprint’s board of directors or any committee thereof will succeed to the authority and responsibility of Sprint’s board of directors or a committee thereof with respect to each assumed RSU and (2) Sprint RSUs which vest subject to achievement of performance objectives that relate to performance periods that have not yet been completed as of the closing date will be treated as if target performance had been achieved as of the closing date but will continue to be subject to the existing vesting provisions during the applicable performance period and thereafter.

Performance Units. At the effective time of the SoftBank Merger, each outstanding Sprint performance unit will be assumed by New Sprint. Each assumed performance unit will be subject to, and vested on, generally the same terms and conditions applicable to such assumed performance unit as of immediately prior to the effective time of the SoftBank Merger except that (1) New Sprint’s board of directors or any committee of the board will succeed to the authority and responsibility of Sprint’s board of directors or a committee of the board with respect to each assumed performance unit and (2) performance units which vest subject to achievement of performance objectives that relate to performance periods that have not been completed as of the closing date will be treated as if target performance had been achieved as of the closing date but will continue to be subject to the existing vesting provisions during the applicable performance period and thereafter. If the holder of a performance unit experiences a termination of employment during the CIC severance protection period (as such term is defined under the applicable Sprint plan) and such holder receives severance benefits under Sprint’s Separation Plan,

Sprint’s Change in Control Severance Plan or an equivalent or greater severance benefit, then all outstanding performance units held by such individual will become vested and non-forfeitable, without pro-ration, and will be paid within thirty (30) days of such termination of employment, subject to applicable tax laws.

Employee Stock Purchase Plan. At the effective time of the SoftBank Merger, each outstanding option to purchase Sprint common stock under the Sprint Employee Stock Purchase Plan (“ESPP”) will be assumed by New Sprint and converted into an option to purchase the number of shares of New Sprint common stock that is equal to the number of shares of Sprint common stock that could have been purchased before the SoftBank Merger upon the exercise of such ESPP option. The exercise price per share of New Sprint common stock for the converted ESPP option will be equal to 95% of the fair market value per share of New Sprint common stock on the purchase date.

Assumption of Sprint Equity Plans. At the effective time of the SoftBank Merger, New Sprint may assume any or all of the Sprint equity plans. If New Sprint elects to do so, it will be entitled to grant stock awards using the share reserves of the applicable assumed Sprint equity plans immediately prior to the effective time of the SoftBank Merger (including any shares returned to such share reserves as a result of the termination of the converted options and converted RSUs).

Deferred Compensation Plans. At the effective time of the SoftBank Merger, all accounts under Sprint’s deferred compensation plans which provide for hypothetical investments in Sprint common stock will be converted into hypothetical investment accounts for New Sprint common stock equal to the number of shares of Sprint common stock credited to such account immediately prior to the effective time multiplied by the “award exchange ratio.” These accounts will generally continue to be governed by the terms of the applicable deferred compensation plans.

“No Solicitation” Provisions. The Merger Agreement contains provisions prohibiting Sprint from seeking an alternative acquisition transaction and requiring Sprint to notify SoftBank of any inquiries, requests, proposals or offers relating to or for any such alternative acquisition transactions. The Merger Agreement does not, however, prohibit Sprint from considering and potentially recommending to its stockholders, or terminating the Merger Agreement and entering into an agreement with respect to, an unsolicited, bona fide written superior offer from a third party under the circumstances described in, and subject to Sprint’s compliance with the terms of, the Merger Agreement. For further information see “The Merger Agreement—No Solicitation of Alternative Offers” beginning on page 144.

Conditions to the Completion of the SoftBank Merger. The obligations of the SoftBank Entities and Sprint to complete the SoftBank Merger and the other transactions contemplated by the Merger Agreement are subject to the satisfaction at or prior to the closing of the SoftBank Merger of the following conditions, which may be waived by Parent and Sprint (to the extent legally permissible):

In addition to the conditions applicable to both the SoftBank Entities and Sprint described above, the obligations of the SoftBank Entities to complete the SoftBank Merger and the other transactions contemplated by the Merger Agreement are subject to the satisfaction at or prior to the completion of the SoftBank Merger of the following additional conditions, which may be waived by Parent (to the extent legally permissible):

In addition to the conditions applicable to the SoftBank Entities and Sprint described above, the obligation of Sprint to complete the SoftBank Merger and the other transactions contemplated by the Merger Agreement is subject to the satisfaction at or prior to the completion of the SoftBank Merger of the following additional conditions, which may be waived by Sprint (to the extent legally permissible):

For further details, see “The Merger Agreement—Conditions to the Completion of the SoftBank Merger” beginning on page 150.

The SoftBank Merger is not conditioned on approval of the Clearwire Acquisition Agreement by Clearwire’s stockholders or the closing of the Clearwire Acquisition.

Termination of the Merger Agreement. The Merger Agreement contains detailed provisions regarding the ability of Parent and Sprint to terminate the Merger Agreement at any time prior to the closing of the SoftBank Merger. Such provisions include the right of either Parent or Sprint to terminate the Merger Agreement:

Furthermore, the SoftBank Entities may terminate the Merger Agreement if:

Furthermore, Sprint may terminate the Merger Agreement if:

For further details, see “The Merger Agreement—Termination of the Merger Agreement” beginning on page 152.

Termination Fee and Expenses. If the Merger Agreement is terminated under specified circumstances, Sprint may be required to pay a termination fee of $600 million or reimbursement of expenses of up to $75 million to Parent. If the Merger Agreement is terminated under other specified circumstances, Parent may be required to pay a “reverse termination fee” of $600 million to Sprint. For further details, see “The Merger Agreement—Termination Fee; Expenses” beginning on page 153 and “The Merger Agreement—Reverse Termination Fee” beginning on page 154.

Summary of the Bond Purchase Agreement (see page 156)

On October 15, 2012, Sprint and Parent entered into the Bond Purchase Agreement, and on October 22, 2012, pursuant to the terms of the Bond Purchase Agreement, Sprint issued and Parent purchased the Bond in the principal amount of $3.1 billion. The Bond, which matures on October 15, 2019, may not be voluntarily prepaid by Sprint in whole or in part before such date. The interest rate on the Bond is 1.0% per annum, which is payable semiannually in arrears on April 15 and October 15 of each year, commencing on April 15, 2013, and accrued and unpaid interest on any portion of the Bond that is converted will be paid in cash simultaneously with the delivery of shares of Sprint common stock upon settlement of such conversion.

At any time after the Merger Agreement has been terminated without the SoftBank Merger having occurred, Parent (or any permitted transferees holding all or portions of the Bond) may convert the Bond (or portions thereof) into Sprint common stock, subject to receipt of all required regulatory approvals, as provided in the Bond Purchase Agreement. Subject to election by Parent, the Bond will automatically convert into Sprint common stock immediately prior to a change of control with respect to Sprint. In addition, the Bond Purchase Agreement provides that the Bond will automatically convert immediately prior to the effective time of the SoftBank Merger. Parent also has the right to convert the Bond immediately prior to any repayment of the Bond. The conversion rate of the Bond is 190.476190322581 shares of Sprint common stock for each $1,000 of principal (equivalent to 590,476,190 shares of Sprint common stock in the aggregate), subject to certain

adjustments, with cash being paid in lieu of any fractional shares, except that in the case of automatic conversion immediately prior to the closing of the SoftBank Merger, the conversion rate will be equal to the number of shares obtained by dividing $1,000 by the last closing sale price of Sprint common stock immediately prior to the closing of the SoftBank Merger (but not below 190.476190322581 shares of Sprint common stock for each $1,000 of principal, subject to certain adjustments).

The Bond Purchase Agreement provides that if the Bond has been fully converted into common stock, and the Merger Agreement has terminated without the SoftBank Merger having occurred, then as long as Parent and its affiliates own (a) at least 10% of the total shares of Sprint common stock, Parent will have the right to designate two members to Sprint’s board of directors and (b) less than 10% but greater than or equal to 5% of the total number of shares of Sprint common stock, Parent will have the right to designate one member to Sprint’s board of directors. If Parent and its affiliates own less than 5% of the total number of shares of Sprint common stock, Parent will have no director designation rights. In addition, Parent’s rights to designate directors on Sprint’s board of directors will terminate if Parent sells or disposes of its economic interest in the shares of Sprint common stock issued upon conversion of the Bond. The Bond Purchase Agreement provides that Sprint will use its commercially reasonable best efforts to ensure that such designated directors are appointed to the Sprint board of directors, including ensuring that the designated directors are recommended by Sprint’s Nominating and Corporate Governance Committee and its board of directors. If the Bond is paid in full and no portion of the Bond is converted into Sprint common stock, the director designation rights of Parent under the Bond Purchase Agreement will expire.

The Bond Purchase Agreement contains various covenants, customary representations and warranties and events of default, and provides certain registration rights to Parent, its affiliates, and holders of 10% or more of Sprint common stock issued pursuant to the conversion of the Bond that has not been sold through a broker or dealer or underwritten in a public securities transaction.

The transactions contemplated by the Bond Purchase Agreement are referred to as the Bond Purchase Transaction.

Summary of the Warrant (see page 161)

At the effective time of the SoftBank Merger, pursuant to the terms of the Merger Agreement, New Sprint will issue to HoldCo the Warrant to purchase up to 54,579,924 fully paid and nonassessable shares of New Sprint common stock (subject to anti-dilution adjustments), at an exercise price of $5.25 per share (subject to anti-dilution adjustments). The Warrant will be exercisable at the option of HoldCo, in whole or in part, at any time after the issuance of the Warrant until the fifth anniversary of the issuance date. The aggregate purchase price of the Warrant may be paid by either cash or, at the option of HoldCo, through a customary cashless exercise process.

The transactions contemplated by the Warrant are referred to as the Warrant Transaction, and the SoftBank Merger, the Equity Contribution, the Bond Purchase Transaction and the Warrant Transaction are collectively referred to as the “Transactions.”

Regulatory Approvals (see page 121)

Hart-Scott Rodino. The transactions contemplated by the Merger Agreement require SoftBank and Sprint to submit antitrust notifications under the HSR Act, and the rules promulgated thereunder by the FTC. Each of SoftBank and Sprint has made the required notifications under the HSR Act, and the Antitrust Division and the FTC granted early termination of the waiting period under the HSR Act on December 6, 2012. SoftBank and Sprint believe that the SoftBank Merger can be effected in compliance with U.S. antitrust laws. However, we cannot assure you that a

challenge to the consummation of the SoftBank Merger on antitrust grounds will not be made or that, if such a challenge were made, SoftBank and Sprint would prevail or would not be required to accept certain conditions, possibly including certain divestitures of substantial assets of SoftBank and/or Sprint, in order to consummate the SoftBank Merger.

Federal Communications Commission Approval. Sprint is also subject to regulation by the FCC under the Communications Act of 1934, as amended (the “Communications Act”). Sprint holds a number of licenses issued by the FCC for the operation of its wireless and wireline assets and for the provision of telecommunications services. The FCC must approve the transfer of control of the licenses held by Sprint to SoftBank as a result of the SoftBank Merger. The FCC will not issue its approval until it receives the consent of certain executive branch government agencies that undertake a national security review of FCC-notified transactions involving potential foreign ownership of U.S. telecommunications assets. These agencies include the Department of Justice, Federal Bureau of Investigation, Department of Homeland Security, and Department of Defense. The FCC also must review the impact of the additional foreign ownership of Sprint that will result from this transaction. As a result of the acquisition of control of Sprint by SoftBank, non-U.S. interests in Sprint will exceed 25%, and under the Communications Act, foreign ownership of wireless common carriers in excess of 25% is permitted unless the FCC determines that the public interest will be served by refusing to permit such holdings. While we believe that FCC approval will ultimately be obtained, this approval is not assured.

CFIUS and DSS Approvals. The SoftBank Merger is also subject to review and clearance by CFIUS under the Defense Production Act of 1950, as amended, including by the Foreign Investment and National Security Act of 2007 (collectively, the “DPA”), which provides for national security reviews of foreign acquisitions of U.S. companies that may have an impact on national security. CFIUS notification is voluntary, but provides a means to assure that the President of the United States will not exercise his authority to block the transaction or require divestiture after closing. In addition, for certain foreign acquisitions of interests in businesses engaged in classified work for U.S. federal government agencies, DSS, acting pursuant to the National Industrial Security Program Operating Manual (“NISPOM”), typically requires that the parties take certain actions to mitigate foreign ownership, control or influence. Such measures are intended to protect against unauthorized disclosures of classified or other sensitive information and technologies as well as other risks to classified work. SoftBank and Sprint will also work with DSS to develop appropriate mitigation measures.

State and International. In addition to U.S. federal regulatory and antitrust approvals, regulatory approvals are also being sought and filings have been made in a number of states in the United States and in two foreign jurisdictions.

Timing of Regulatory Approvals. We currently anticipate that required regulatory approvals will be received by mid-2013, although the receipt of these approvals and their timing cannot be assured or predicted at this time.

Impact of Clearwire Acquisition. Sprint and Clearwire have made filings and taken other actions, and will continue to take actions, necessary to obtain governmental approvals in connection with the Clearwire Acquisition and related transactions. Several governmental agencies have elected to review the Clearwire Acquisition together with the SoftBank Merger, which could have the effect of delaying approval for, and closing of, the SoftBank Merger. While Sprint and New Sprint believe that required regulatory approvals for the SoftBank Merger and the Clearwire Acquisition will ultimately be obtained, these approvals are not assured.

Tax Consequences of the SoftBank Merger (see page 162)

Sprint will not be required to complete the SoftBank Merger unless it receives a legal opinion to the effect that the exchanges that occur pursuant to the SoftBank Merger, taken together, will constitute exchanges described in Section 351 of the Code, for U.S. federal income tax purposes. Assuming the exchanges so qualify, no gain or loss

will be recognized by Sprint as a result of the SoftBank Merger and the tax consequences to Sprint stockholders as a result of the SoftBank Merger generally will be as follows:

Tax matters relating to the SoftBank Merger are very complicated and the tax consequences of the SoftBank Merger to Sprint stockholders will depend on the facts of their own situations. Sprint stockholders are urged to consult their own tax advisors for a full understanding of the tax consequences of the SoftBank Merger.

Overview of the Comparison of Rights of Holders of Sprint Common Stock and New Sprint Common Stock (see page 168)

New Sprint’s authorized capital stock will consist of 9,000,000,000 shares of common stock, 1,000,000,000 shares of non-voting common stock and 20,000,000 shares of preferred stock. Sprint’s current authorized capital stock consists of 6,000,000,000 shares of Series 1 common stock, par value $2.00 per share, 500,000,000 shares of Series 2 common stock, par value $2.00 per share (together with the Series 1 common stock, the “Voting Common Stock”), 100,000,000 shares of non-voting common stock, par value $0.01 per share, and 20,000,000 shares of preferred stock, no par value. The material differences between the rights of holders of Sprint common stock and New Sprint common stock are summarized below:

Limitations, Restrictions and Conditions on SoftBank’s Conduct of Business and Exercise of Rights (see page 180)

Pursuant to the Merger Agreement, SoftBank has agreed to the adoption of certain provisions in New Sprint’s certificate of incorporation and bylaws, which will be in effect at the effective time of the SoftBank

Merger, that will have the effect of limiting, restricting or conditioning the conduct of business by SoftBank and its subsidiaries and HoldCo’s exercise of rights as the holder of a majority of the outstanding shares of New Sprint common stock.

Required Approvals for Certain Actions. The New Sprint bylaws as in effect at the effective time of the SoftBank Merger will provide that during the 24 months immediately following the effective time of the SoftBank Merger, the following matters will require, in addition to any approval required by law, the approval of both (i) the New Sprint board of directors and (ii) a majority of “Independent Directors” (as such term is defined in the NYSE listing rules) who have no interest in the matter being voted upon:

Conduct of Competing Businesses by SoftBank. The New Sprint certificate of incorporation as in effect at the effective time of the SoftBank Merger will provide that SoftBank will refrain from conducting or acquiring certain competing businesses unless and until the combined voting interest of SoftBank and its controlled affiliates in New Sprint remains below 10% for 90 consecutive days, subject to certain exceptions.

Allocation of Corporate Opportunities. The New Sprint certificate of incorporation as in effect at the effective time of the SoftBank Merger will not limit the right of SoftBank or its controlled affiliates to pursue or take advantage of corporate opportunities that may be available both to them or to New Sprint, except as to potential transactions or other matters that (i) relate solely to a competing business as defined in the New Sprint certificate of incorporation, and (ii) were offered to a director, officer or employee of SoftBank who is also a director or officer of New Sprint expressly in such person’s capacity as a director or officer of New Sprint.

Mandatory Offer to Purchase. The New Sprint certificate of incorporation as in effect at the effective time of the SoftBank Merger will provide that, in the event that the combined voting interest of SoftBank and its controlled affiliates in New Sprint exceeds 85% of the outstanding voting securities of New Sprint, then SoftBank or a controlled affiliate will make an offer to acquire all the remaining shares of New Sprint common stock at a price not less than the volume-weighted average closing price of New Sprint common stock for the 20 consecutive trading days immediately preceding such offer.

Security Ownership of Certain Beneficial Owners and Management of Sprint (see page 184)

As of the meeting record date, directors and executive officers of Sprint and their affiliates owned and were entitled to vote 6,229,475 shares of Sprint common stock, or less than 1% of the shares of Sprint common stock issued and outstanding on that date. In addition, the known beneficial owners of 5% or more of Sprint’s common stock, excluding SoftBank, owned and were entitled to vote 804,741,415 shares of Sprint common stock, or approximately 26.7% of the shares of Sprint common stock issued and outstanding as of the record date for the special stockholders’ meeting. Although SoftBank may be deemed to beneficially own 16.4% of Sprint’s common stock, as such holdings are based solely on SoftBank’s beneficial ownership of Sprint common stock underlying the Bond, such shares will not be issued and outstanding as of the meeting record date and therefore may not be voted at the special stockholders’ meeting.

Appraisal Rights (see page 132)

Under the Merger Agreement, Sprint stockholders of record who do not vote in favor of the Merger Proposal and who otherwise comply with the procedures for exercising appraisal rights under the KGCC will be entitled to appraisal rights in connection with the SoftBank Merger and, if the SoftBank Merger is completed, obtain payment in cash of the fair value of their shares of Sprint common stock as determined by the Kansas district court, instead of the merger consideration. Merely not voting in favor of the Merger Proposal will not preserve the right of Sprint stockholders to appraisal of their shares of Sprint common stock under the KGCC. Sprint stockholders who desire to exercise their appraisal rights must submit a written demand for an appraisal before the vote on the Merger Proposal at the special stockholders’ meeting. Following the effective time of the SoftBank Merger, such stockholders must also comply with other procedures as required by the KGCC. Due to the complexity of these procedures, Sprint stockholders who are considering exercising such rights are encouraged to seek the advice of legal counsel. These procedures are summarized under the heading, “The SoftBank Merger—Appraisal Rights” beginning on page 132.

All references in Section 17-6712 of the KGCC and this summary to a “stockholder” are to a record holder of the shares of Sprint common stock as to which appraisal rights are asserted. A person having a beneficial interest in “street name” in shares of Sprint common stock held of record in the name of another person, such as a broker or nominee, must act promptly to cause such record holder to follow properly the steps summarized below and in a timely manner to perfect appraisal rights.

Any share of Sprint common stock that, as of the effective time of the SoftBank Merger, is held by a holder who is entitled to and who has properly preserved appraisal rights will not be converted into or represent the right to receive the applicable merger consideration, and the holder of such share will be entitled only to such rights as may be granted to such holder pursuant to Section 17-6712 of the KGCC with respect to such share. However, if such appraisal rights have not been perfected or the holder of such share has otherwise lost such holder’s appraisal rights with respect to such share, then, as of the later of the effective time of the SoftBank Merger or the time of the failure to perfect such rights or the loss of such rights, such share will automatically be converted into and will represent only the right to receive (upon the surrender of the certificate representing such share) the merger consideration payable to holders of shares of Sprint common stock that have elected to receive cash in the SoftBank Merger, notwithstanding any election that a holder may have made with respect to such share.

Any holder of Sprint common stock who wishes to exercise appraisal rights, or who wishes to preserve such holder’s right to do so, should review the discussion under the caption “Appraisal Rights” and Annex F carefully because failure to timely and properly comply with the procedures specified therein will result in the loss of appraisal rights. Annex F to this proxy statement-prospectus contains the full text of Section 17-6712 of the KGCC, which describes the rights of appraisal and related requirements. Sprint

encourages you to read these provisions carefully and in their entirety. Failure to strictly comply with these provisions will result in loss of the right of appraisal.

Recent Developments (see page 46)

On April 15, 2013, Sprint announced that it had received an unsolicited proposal from DISH to acquire Sprint. Sprint announced that its board of directors will review the DISH Proposal carefully and consistent with its fiduciary and legal duties. The Sprint board of directors subsequently established the Sprint Special Committee to assess the DISH Proposal. The Sprint board of directors has not made any determination to change its unanimous recommendation of the SoftBank Merger. It is not possible at this time to predict when or if the Sprint Special Committee and the Sprint board of directors will make any determination with respect to the DISH Proposal. There is no obligation under the Merger Agreement for any such determination to be made within a specified time period.

Risks Associated with the SoftBank Merger, New Sprint and Sprint (see page 48)

The SoftBank Merger (including the possibility that the SoftBank Merger may not be completed) poses a number of risks to Sprint and its stockholders. In addition, New Sprint is subject to various additional risks, including risks related to SoftBank controlling New Sprint. You should carefully consider the following risks, including the risks discussed in the section entitled “Risk Factors,” before investing in our common stock:

Interests of Certain Sprint Directors and Executive Officers in the SoftBank Merger (see page 115)

Certain of Sprint’s executive officers and directors have financial interests in the SoftBank Merger that are different from, or in addition to, the interests of Sprint’s stockholders. The members of the Sprint board of directors were aware of and considered these interests, among other matters, in evaluating and negotiating the Merger Agreement and the SoftBank Merger and in recommending to Sprint stockholders that the Merger Agreement be adopted. These interests are described in more detail in “The SoftBank Merger—Interests of Certain Sprint Directors and Executive Officers in the SoftBank Merger” beginning on page 115.

Board of Directors and Management Following the SoftBank Merger (see page 177)

During the 24 months immediately following the effective time of the SoftBank Merger, the New Sprint board of directors will consist of ten members, determined as follows:

In addition, during the 12 months immediately following the period described above, the New Sprint board of directors will consist of ten members, determined as follows:

Each director of New Sprint will remain in office until his or her earlier resignation or successors are elected in accordance with the bylaws of New Sprint.

At all times following the period described above until such time as the combined voting interest of SoftBank and its controlled affiliates in New Sprint falls below 50% and remains below 50% for 90 consecutive days, the New Sprint board of directors will include not fewer than three (or such greater number as may be required by applicable law or listing rules) individuals who qualify as “Independent Directors” (as such term is defined in the NYSE listing rules). Thereafter, unless and until the combined voting interest of SoftBank and its controlled affiliates in New Sprint remains below 10% for 90 consecutive days, the New Sprint board of directors will include a number of individuals nominated by SoftBank or its controlled affiliate that is proportional to the combined voting interest of SoftBank and its controlled affiliates in New Sprint, rounded up to the nearest whole number.

As of the date of this proxy statement-prospectus, at the effective time of the SoftBank Merger, the following individuals are expected to serve on the New Sprint board of directors:

Other than the individuals noted above, SoftBank and Sprint have not determined who will serve on the New Sprint board of directors.

Upon the consummation of the SoftBank Merger, the executive officers of New Sprint will be determined by the New Sprint board of directors. Other than Mr. Hesse, who is expected to be appointed as the initial Chief Executive Officer of New Sprint, as of the date of this proxy statement-prospectus, SoftBank and Sprint have not determined who will serve as the officers of New Sprint at the effective time of the SoftBank Merger. In addition, it is expected that at the effective time of the SoftBank Merger, Mr. Son would be appointed as the initial Chairman of the New Sprint board of directors and Mr. Fisher would be appointed as the initial Vice-Chairman of the New Sprint board of directors.

SUMMARY HISTORICAL FINANCIAL DATA

The following selected historical consolidated financial data of Sprint have been derived from the audited historical consolidated financial statements and related notes of Sprint as of and for each of the five years in the period ended December 31, 2012. The selected historical consolidated financial data provide only a summary and should be read in conjunction with the audited consolidated financial statements and notes thereto, other financial information and “Management’s Discussion and Analysis of Financial Condition and Results of Operations” contained in Sprint’s filings with the SEC. See “Where You Can Find More Information” on page 187. Historical results are not necessarily indicative of any results to be expected in the future.

UNAUDITED PRO FORMA CONDENSED COMBINED FINANCIAL INFORMATION

These unaudited pro forma condensed combined financial statements give effect to transactions related to (a) the proposed merger (the “SoftBank Merger”) whereby Sprint Nextel Corporation (“Sprint”) would become a wholly owned subsidiary of Starburst II, Inc. (“Starburst II,” “New Sprint” or “Parent”) and (b) Sprint’s proposed acquisition of all of the remaining equity interests in Clearwire Corporation (“Clearwire”) not currently held by Sprint (the “Clearwire Acquisition”). The unaudited pro forma condensed combined balance sheet includes the historical audited consolidated balance sheets of Starburst II, Sprint and Clearwire, as of December 31, 2012, giving pro forma effect to (i) the SoftBank Merger and the Clearwire Acquisition as discussed above and (ii) the additional equity capitalization of Parent, as if these transactions had been consummated on December 31, 2012. The unaudited pro forma condensed combined statement of operations was prepared using the historical audited consolidated statement of operations of Starburst II for the period from October 5, 2012 (date of incorporation) through December 31, 2012, and the historical audited consolidated statements of operations of Sprint and Clearwire for the year ended December 31, 2012, giving pro forma effect to the acquisitions as if these transactions had been consummated on January 1, 2012. The unaudited pro forma condensed combined financial information has been adjusted to give pro forma effect to agreements and events that are (1) directly attributable to the SoftBank Merger and Clearwire Acquisition, (2) factually supportable, and (3) with respect to the statement of operations, expected to have a continuing impact on the combined results.

SoftBank Transaction

On October 5, 2012, Parent was established by SoftBank for the purpose of acquiring a controlling interest in Sprint and undertaking the transactions contemplated by the Merger Agreement and the Bond Purchase Agreement (collectively, the “SoftBank Transactions”). For more details about the SoftBank Transactions, see “The Merger Agreement” beginning on page 136 and “The Bond Purchase Agreement” beginning on page 156.

The completion of the SoftBank Transactions is expected to occur in stages. On October 22, 2012, Sprint issued a convertible bond (“Bond”) under the Bond Purchase Agreement to Parent with a face amount of $3.1 billion, stated interest rate of 1%, and maturity date of October 15, 2019. The Bond is convertible into approximately 590 million shares of Sprint common stock, subject to adjustment. The Bond will convert into shares of Sprint common stock immediately prior to consummation of the SoftBank Merger and may not otherwise be converted prior to the termination of the Merger Agreement.

Upon consummation of the SoftBank Merger, which is subject to various conditions, including Sprint stockholder and regulatory approval, SoftBank will fund Parent with additional capital of approximately $17.0 billion, of which approximately $12.1 billion will be distributed to Sprint stockholders as merger consideration with the remaining $4.9 billion held in the cash balance of New Sprint for general corporate purposes, including but not limited to the Clearwire Acquisition. Pursuant to the terms and subject to the conditions described in the Merger Agreement, upon consummation of the SoftBank Merger, outstanding shares of Sprint common stock, except as otherwise provided for in the Merger Agreement, will be converted, at the election of Sprint stockholders, into (i) cash in an amount equal to $7.30 for each share of Sprint common stock or (ii) one share of New Sprint common stock for each share of Sprint common stock, subject in each case to proration such that a stockholder may receive a combination of cash and New Sprint common stock. See “The SoftBank Merger—Cash/Stock Proration and Allocation Rules” beginning on page 126.

Upon consummation of the SoftBank Merger, HoldCo, New Sprint’s parent, will receive a five-year warrant to purchase approximately 55 million shares of New Sprint at $5.25 per share which would yield approximately $300 million in proceeds upon exercise. No pro forma adjustment for the warrant has been reflected in the unaudited pro forma condensed combined balance sheet due to its immateriality. See “The Warrant Agreement” beginning on page 161. Upon consummation of the SoftBank Merger, (i) Sprint will become a wholly-owned subsidiary of New Sprint, (ii) New Sprint will be a publicly traded company, (iii) SoftBank will indirectly own

approximately 70% of New Sprint on a fully diluted basis, and (iv) the former stockholders and other equityholders of Sprint will own approximately 30% of the fully diluted equity of New Sprint.

As more fully described in the notes to the unaudited pro forma condensed combined financial information, the estimate of total consideration paid by Parent in exchange for 100% of the outstanding shares of Sprint, excluding the 590 million common shares expected to be held by New Sprint, is determined based primarily upon the approximately $12.1 billion cash consideration plus the stock consideration equal to the estimated fair value of New Sprint shares of common stock to be distributed to Sprint stockholders existing immediately prior to the consummation of the SoftBank Merger.

Clearwire Transactions

On December 17, 2012, Sprint announced the Clearwire Acquisition pursuant to an agreement and plan of merger dated as of December 17, 2012. The completion of the Clearwire Acquisition is subject to various conditions including Clearwire stockholder and regulatory approval, and the consummation of the SoftBank Merger, among other things. Upon the closing of the Clearwire Acquisition, Sprint has agreed to pay to Clearwire stockholders cash in an amount equal to $2.97 per share equaling $2.2 billion in exchange for all shares of Clearwire common stock not currently held by Sprint.

On December 17, 2012, Clearwire and Sprint entered into agreements that provide up to $800 million of additional financing for Clearwire in the form of exchangeable notes, which will be convertible into Clearwire common stock at $1.50 per share, subject to certain conditions and subject to adjustment, pursuant to the terms of such financing agreements. Under the financing agreements, Clearwire has the right to sell to Sprint up to $80 million of exchangeable notes per month for up to ten months beginning in January 2013, subject to certain conditions including the consummation of the proposed Clearwire Acquisition. Refer to Note 10—Subsequent Events for additional information.

Unaudited Pro Forma Condensed Combined Financial Statement Considerations

The unaudited pro forma condensed combined financial information was prepared treating Parent as the acquiring entity for purposes of the SoftBank Merger and Sprint as the acquiring entity for purposes of the Clearwire Acquisition. Accordingly, consideration paid by Parent to acquire the ownership interest of Sprint will be allocated to the assets acquired and liabilities assumed from Sprint, and consideration paid by Sprint in the Clearwire Acquisition, as well as the estimated fair value of Sprint’s previously held interest in Clearwire, will be allocated to the assets acquired and liabilities assumed from Clearwire, based upon their estimated fair values as of the acquisition date of each respective transaction. The unaudited pro forma condensed combined financial information is based on various assumptions, including assumptions relating to the consideration paid and the allocation thereof to the assets acquired and the liabilities assumed from Sprint and Clearwire based on preliminary estimates of fair value.

Additionally, the allocations of the fair value of the consideration paid in excess of Sprint’s and Clearwire’s historical book value is dependent upon certain valuations and other studies that have not yet been finalized. A final estimate of the fair value of Sprint’s and Clearwire’s assets and liabilities will be based on the actual net tangible and intangible assets that exist at the acquisition date of each transaction, which will not be known prior to the consummation of each transaction. Accordingly, the pro forma consideration paid by the acquirers and the associated purchase price adjustments are preliminary, subject to future adjustments which may be material and have been made solely for the purpose of providing the unaudited pro forma condensed combined financial information presented below. The final purchase prices and the allocations thereof may differ materially from those reflected in the unaudited pro forma condensed combined financial information after final valuation procedures are performed and amounts are finalized following completion of the transactions.

This unaudited pro forma condensed combined financial information should be read in conjunction with the audited historical financial information and accompanying notes of Parent, beginning on page F-2, of Sprint, which are incorporated by reference in this proxy statement-prospectus, and of Clearwire, which are included in Sprint’s Annual Report on Form 10-K for the year ended December 31, 2012, which is incorporated by reference into this proxy statement-prospectus. The unaudited pro forma condensed combined financial information is not necessarily indicative of the operating results or financial position that would have occurred if the SoftBank Merger and Clearwire Acquisition had been consummated at the dates specified and is not indicative of operations going forward. The unaudited pro forma condensed combined statement of operations does not reflect any cost savings from operating efficiencies, synergies or other restructurings that could result from the proposed SoftBank Merger and Clearwire Acquisition.

Starburst II

Unaudited Pro Forma Condensed Combined Balance Sheet

As of December 31, 2012

(in millions)