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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): October 21, 2015

SANDISK CORPORATION

(Exact name of registrant as specified in its charter)

951 SanDisk Drive, Milpitas, California 95035

(Address of principal executive offices) (Zip Code)

Registrant’s telephone number, including area code: (408) 801-1000

N/A

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

x                                  Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

x                                  Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o                                    Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o                                    Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

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Item 2.02 Results of Operations and Financial Condition

On October 21, 2015, SanDisk Corporation (“SanDisk” or the “Company”) issued a press release to report its financial results for its third quarter ended September 27, 2015.

The press release, related Prepared Remarks for Investors and investor presentation are attached hereto as Exhibits 99.1, 99.2 and 99.3, respectively, and are incorporated herein in their entirety by reference.  In addition to the preliminary condensed consolidated financial statements presented in accordance with generally accepted accounting principles (GAAP), the attached documents contains non-GAAP measures of operating results, net income and net income per share, which are adjusted from results based on GAAP to exclude certain expenses, gains and losses.  These non-GAAP financial measures are provided to enhance the user’s overall understanding of SanDisk’s current financial performance and its prospects for the future.  Specifically, SanDisk believes the non-GAAP results provide useful information to both management and investors as these non-GAAP results exclude certain expenses, gains and losses that it believes are not indicative of its core operating results and because they are consistent with the financial models and estimates published by many analysts who follow SanDisk.  For example, because the non-GAAP results exclude the expenses SanDisk recorded for share-based compensation, inventory step-up expense, amortization of acquisition-related intangible assets related to acquisitions of Pliant Technology, Inc. in May 2011, FlashSoft Corporation in February 2012, Schooner Information Technology, Inc. in June 2012, SMART Storage Systems in August 2013 and Fusion-io, Inc. in July 2014, impairment of acquisition-related in-process research and development intangible assets, non-cash economic interest expense associated with SanDisk’s convertible senior notes, non-cash change in fair value of the liability component of the convertible senior notes due to the conversion of a portion of the 1.5% Convertible Senior Notes due 2017 and related tax adjustments, SanDisk believes the inclusion of non-GAAP financial measures provides consistency in its financial reporting.  In addition, SanDisk’s non-GAAP diluted shares are adjusted for the impact of expensing share-based compensation and include the impact of SanDisk’s call options which, when exercised, will offset the issuance of dilutive shares from SanDisk’s convertible senior notes, while SanDisk’s GAAP diluted shares exclude the anti-dilutive impact of these call options.  These non-GAAP results are some of the primary indicators management uses for assessing SanDisk’s performance, allocating resources, and planning and forecasting future periods.  Further, management uses non-GAAP information that excludes certain non-cash charges, such as share-based compensation, inventory step-up expense, amortization of acquisition-related intangible assets, impairment of acquisition-related in-process research and development intangible assets, non-cash economic interest expense associated with the convertible senior notes, non-cash change in fair value of the liability component of the convertible senior notes due to the conversion of a portion of the 1.5% Convertible Senior Notes due 2017 and related tax adjustments, as these non-GAAP charges do not reflect the cash operating results of the business or the ongoing results.  These measures should be considered in addition to results prepared in accordance with GAAP, but should not be considered a substitute for, or superior to, GAAP results.  These non-GAAP measures may be different than the non-GAAP measures used by other companies.

The information contained herein and in the accompanying exhibits shall not be incorporated by reference into any filing of SanDisk, whether made before or after the date hereof, regardless of any general incorporation language in such filing, unless expressly incorporated by specific reference in such filing.

Forward Looking Statements

All statements included or incorporated by reference in this document, other than statements or characterizations of historical fact, are forward-looking statements within the meaning of the federal securities laws, including Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended.  These forward-looking statements are based on SanDisk’s current expectations, estimates and projections about its business and industry, management’s beliefs, and certain assumptions made by SanDisk and Western Digital Corporation (“Western Digital” or “Parent”), all of which are subject to change.  Forward-looking statements can often be identified by words such as “anticipates,” “expects,” “intends,” “plans,” “predicts,” “believes,” “seeks,” “estimates,” “may,” “will,” “should,” “would,” “could,” “potential,” “continue,” “ongoing,” similar expressions, and variations or negatives of these words.  Examples of such forward-looking statements include, but are not limited to, references to the anticipated benefits of the proposed merger contemplated by the merger agreement that has been entered into among SanDisk, Western Digital and Schrader Acquisition Corporation and the expected date of closing of the merger.  These forward-looking statements are not guarantees of future results and are subject to risks, uncertainties and assumptions that could cause actual results to differ materially and adversely from those expressed in any forward-looking statement.

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Important risk factors that may cause such a difference in connection with the proposed merger include, but are not limited to, the following factors: (1) the inability to complete the merger due to the failure to obtain stockholder approval for the merger or the failure to satisfy other conditions to completion of the merger, including the receipt of all regulatory approvals related to the merger; (2) uncertainties as to the timing of the consummation of the merger and the ability of each party to consummate the merger; (3) risks that the proposed merger disrupts the current plans and operations of Western Digital or SanDisk; (4) the ability of Western Digital and SanDisk to retain and hire key personnel; (5) competitive responses to the proposed merger; (6) unexpected costs, charges or expenses resulting from the merger; (7) the outcome of any legal proceedings that could be instituted against Western Digital, SanDisk or their respective directors related to the Merger Agreement; (8) potential adverse reactions or changes to business relationships resulting from the announcement or completion of the merger; (9) the inability to obtain, or delays in obtaining, cost savings and synergies from the merger; (10) delays, challenges and expenses associated with integrating the combined companies’ existing businesses and the indebtedness planned to be incurred in connection with the merger; and (11) legislative, regulatory and economic developments.  These risks, as well as other risks associated with the proposed merger, will be more fully discussed in the joint proxy statement/prospectus that will be included in the Registration Statement on Form S-4 that will be filed with the SEC in connection with the proposed merger.  The forward-looking statements in this document speak only as of this date. Neither SanDisk nor Western Digital undertake any obligation to revise or update publicly any forward-looking statement to reflect future events or circumstances.

In addition, actual results are subject to other risks and uncertainties that relate more broadly to SanDisk’s overall business, including those more fully described in SanDisk’s filings with the Securities and Exchange Commission (“SEC”) including its annual report on Form 10-K for the fiscal year ended December 28, 2014, and its quarterly reports filed on Form 10-Q for the current fiscal year, and Western Digital’s overall business and financial condition, including those more fully described in Western Digital’s filings with the SEC including its annual report on Form 10-K for the fiscal year ended July 3, 2015.  The forward-looking statements in this document speak only as of date of this document.  We undertake no obligation to revise or update publicly any forward-looking statement, except as required by law.

Additional Information And Where To Find It

This communication does not constitute an offer to sell or the solicitation of an offer to buy any securities or a solicitation of any vote or approval nor shall there be any sale of securities in any jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such jurisdiction. Western Digital will file with the SEC a Registration Statement on Form S-4 that will include a joint proxy statement/prospectus of SanDisk and Western Digital.  Each of SanDisk and Western Digital will provide the joint proxy statement/prospectus to their respective stockholders.  SanDisk and Western Digital also plan to file other documents with the SEC regarding the proposed merger.  This document is not a substitute for the joint proxy statement/prospectus or registration statement or any other document which SanDisk or Western Digital may file with the SEC in connection with the proposed merger.  INVESTORS AND SECURITY HOLDERS OF SANDISK AND WESTERN DIGITAL ARE URGED TO READ THE JOINT PROXY STATEMENT/PROSPECTUS AND ANY OTHER RELEVANT DOCUMENTS THAT WILL BE FILED WITH THE SEC CAREFULLY AND IN THEIR ENTIRETY WHEN THEY BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE PROPOSED MERGER.  You may obtain copies of all documents filed with the SEC regarding this merger, free of charge, at the SEC’s website (www.sec.gov).  In addition, copies of the documents filed with the SEC by SanDisk will be available free of charge on SanDisk’s website at http://www.sandisk.com.  Copies of the documents filed with the SEC by Western Digital will be available free of charge on Western Digital’s website at http://www.westerndigital.com.

Participants in the Solicitation

SanDisk, Western Digital, and certain of their respective directors, executive officers and other members of management and employees, under SEC rules may be deemed to be participants in the solicitation of proxies from SanDisk and Western Digital stockholders in connection with the proposed merger.  You can find more detailed information about SanDisk’s executive officers and directors in its definitive proxy statement filed with the SEC on April 27, 2015.  You can find more detailed information about Western Digital’s executive officers and directors in its definitive proxy statement filed with the SEC on September 23, 2015.  Information regarding the persons who may, under the rules of the SEC, be deemed participants in the solicitation of stockholders in connection with the proposed merger will be set forth in the joint proxy statement/prospectus when it is filed with the SEC.  Additional information about SanDisk’s executive officers and directors and Western Digital’s executive officers and directors can be found in the joint proxy statement/prospectus regarding the proposed merger when it is filed with the SEC.

Item 9.01 Financial Statements and Exhibits

(d) Exhibits

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SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

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EXHIBIT INDEX