WESTERN DIGITAL CORP

Summary Description of the Plan

The principal terms of the ESPP are summarized below. The following summary is qualified in its entirety by the full text of the Amended and Restated ESPP, which has been included as Appendix B to the version of this Proxy Statement filed with the SEC. As used below, references to the ESPP also refer to the Amended and Restated ESPP.

Purpose

The purpose of the ESPP is to provide an incentive for present and future eligible employees of our company and our participating subsidiaries to acquire a proprietary interest (or increase an existing proprietary interest) in our company through the purchase of common stock. The ESPP is designed to align the interests of employees with those of our stockholders by fostering a sense of ownership and encouraging long-term commitment to our success. Our Board of Directors believes that continued implementation of the ESPP supports our long-term growth strategy by directly linking employee incentives to stockholder value creation.

Operation of the ESPP

The ESPP operates in a series of periods referred to as “Offering Periods.” We will establish the duration of each Offering Period in advance of that Offering Period. However, an Offering Period may not be longer than 24 months. We may provide for a new Offering Period to start before an Offering Period in progress has ended, but no one participant may participate in more than one Offering Period at the same time.

On the first day of each Offering Period (referred to as the “Enrollment Date”), each eligible employee who has timely filed a valid election to participate in the ESPP for that Offering Period is granted an option to purchase shares of our common stock. Participants may designate in their election the percentage of their compensation to be withheld from their pay during that Offering Period for the purchase of stock under the ESPP. Participants’ contributions under the ESPP are credited to a bookkeeping account in their name. Participants generally may elect to terminate their contributions to the ESPP at any time during an Offering Period. Participants also generally may elect to increase or decrease the rate of their contributions to the ESPP up to four times in a calendar year. Amounts contributed to the ESPP constitute general corporate assets of our company and may be used for any corporate purpose.

An Offering Period may consist of one or more periods referred to as “Exercise Periods.” The last day of each Exercise Period is referred to as an “Exercise Date.” Each option granted under the ESPP for an Offering Period is automatically exercised on each Exercise Date that occurs within that Offering Period. The number of shares acquired by participants upon exercise of their option is determined by dividing the participant’s account balance under the ESPP as of the Exercise Date by the Exercise Price for that Offering Period. We establish the methodology for setting the Exercise Price in an Offering Period in advance of that Offering Period. The administrator of the ESPP may set the Exercise Price at any price, except that in no event may the Exercise Price be lower than the lesser of (i) 85% of the fair market value of a share of our common stock on the applicable Enrollment Date, or (ii) 85% of the fair market value of a share of our common stock on the applicable Exercise Date. Participant accounts are reduced upon exercise of their options by the amount used to pay the Exercise Price of the shares acquired by the participant. No interest is paid to any participant or credited to any account under the ESPP.

Eligibility

Only certain employees are eligible to participate in the ESPP. To be eligible to participate in an Offering Period, on the Enrollment Date of that period an individual must:

lbe employed by our company or one of our subsidiaries that has been designated as a participating subsidiary; and

lbe customarily employed for more than twenty hours per week and more than five months in a calendar year.

An employee who is a citizen or resident of a foreign jurisdiction to whom the grant of an option under the ESPP would be prohibited under the laws of such foreign jurisdiction, or compliance with the laws of such foreign jurisdiction would cause the ESPP to violate the requirements of Section 423 of the Internal Revenue Code, would not be eligible to participate in the ESPP. As of June 27, 2025 approximately 39,967 employees of our company and our subsidiaries, including all of the named executive officers who then remained employed by our company, were eligible to participate in the ESPP.

Limits on Authorized Shares; Limits on Contributions

Currently, a maximum of 44,296,610 shares of our common stock are available for delivery under the plan. As of June 27, 2025, a total of 3,961,426 shares of our common stock remained available for issuance under the ESPP. If stockholders approve this Proposal 3, the number of shares available for issuance under the Amended and Restated ESPP will be increased by an additional 8 million shares, from 44,296,610 shares to 52,296,610 shares.

Participation in the ESPP is also subject to the following limits:

l Participants cannot contribute more than 10% of their compensation to the purchase of stock under the ESPP in any one payroll period.

l Participants cannot be granted an option under the ESPP for an offering period with respect to a number of shares of our common stock that exceeds five times the number of shares determined by dividing (i) $40,000 by (ii) the fair market value of a share of our common stock on the Enrollment Date multiplied by 85% (or the applicable percentage used to calculate the Exercise Price for that Offering Period).

l Participants cannot purchase more than $25,000 of stock (valued at the start of the applicable Offering Period and without giving effect to any discount reflected in the purchase price for the stock) under the ESPP for each calendar year in which such option is outstanding.

l Participants will not be granted an option under the ESPP if it would cause the participant to own stock and/or hold outstanding options to purchase stock representing 5% or more of the total combined voting power or value of all classes of stock of our company or one of our subsidiaries or to the extent it would exceed certain other limits under the Internal Revenue Code.

Our company has the flexibility to change the 10% contribution limit referred to above and the maximum limit on the number of shares that may be acquired by any individual during an Offering Period or Exercise Period under the ESPP referred to above from time to time without stockholder approval. However, we cannot increase the aggregate number of shares available for delivery under the ESPP without stockholder approval, other than to reflect stock splits and similar adjustments as described below. The $25,000 and the 5% ownership limitations referred to above are required under the Internal Revenue Code.

Adjustments

The number and kind of shares available under the ESPP, as well as purchase prices and share limits under the ESPP, are subject to adjustment in the case of certain corporate events. These events include reclassifications, recapitalizations, stock splits (including a stock split in the form of a stock dividend) or reverse stock split, mergers, combinations, consolidations, other reorganization, spin-off, split-up, similar extraordinary dividend distribution in respect of our common stock, exchange of common stock or other securities of our company, or other similar, unusual or extraordinary corporate events in respect of our common stock.

Termination of Participation

A participant’s election to participate in the ESPP will generally continue in effect for all Offering Periods until the participant files a new election that takes effect or the participant ceases to participate in the ESPP. A participant’s participation in the ESPP generally will terminate if, prior to the applicable Exercise Date, the participant ceases to be employed by our company or one of our participating subsidiaries or the participant is no longer scheduled to work more than twenty hours per week or more than five months in a calendar year.

If a participant’s participation in the ESPP terminates during an Offering Period for any of the reasons discussed in the preceding paragraph, he or she will no longer be permitted to make contributions to the ESPP for that Offering Period and, subject to limited exceptions, his or her option for that Offering Period will automatically terminate and his or her account balance will be paid to him or her in cash without interest. However, a participant’s termination from participation will not have any effect upon his or her ability to participate in any succeeding Offering Period, provided that the applicable eligibility and participation requirements are again then met.

Transfer Restrictions

Participants rights with respect to options or the purchase of shares under the ESPP, as well as contributions credited to their accounts, may not be transferred, assigned, pledged or otherwise disposed of in any way except by will or the laws of descent and distribution.

Administration

The ESPP is administered by our Board or by a committee appointed by our Board. Our Board has appointed the Compensation and Talent Committee as the current administrator of the ESPP. The administrator has full power and discretion to adopt, amend or rescind any rules and regulations for carrying out the ESPP, to determine which (if any) of our company’s subsidiaries may be participating subsidiaries whose employees may participate in the ESPP, and to construe and interpret the ESPP. The administrator also may adopt rules, procedures or sub-plans applicable to particular subsidiaries or locations (for example and without limitation, as to participants employed in a particular jurisdiction outside of the U.S. who are subject to other applicable laws and regulations), which sub-plans may be designed to be outside of the scope of Section 423 of the Internal Revenue Code and need not comply with the otherwise applicable provisions of the ESPP. Decisions of the administrator with respect to the ESPP are final and binding on all persons.

No Limit on Other Plans

The ESPP does not limit the ability of our Board or any committee of our Board of Directors to grant awards or authorize any other compensation, with or without reference to our common stock, under any other plan or authority.

Amendments

Our Board of Directors generally may amend or suspend the ESPP at any time and in any manner. No amendment, suspension or termination of the ESPP may have a material adverse effect on the then-existing rights of any participant during an Exercise Period without the participant’s written consent, but our Board may amend, suspend or terminate the ESPP as to any outstanding options granted under the ESPP for an Offering Period, effective as of any Exercise Date within that Offering Period, without the consent of the participants to whom such options were granted. Stockholder approval for an amendment to the ESPP will only be required to the extent required by law or applicable stock exchange rules, or as necessary to meet the requirements of Section 423 of the Internal Revenue Code in order to preserve the intended tax consequences of the ESPP.

Termination

Our Board of Directors may terminate the ESPP at any time. The ESPP will also terminate earlier if all of the shares authorized under the ESPP have been purchased.

Material U.S. Federal Income Tax Consequences of Awards Under the Plan

The material U.S. federal income tax consequences of the Amended and Restated ESPP under current federal law, which is subject to change, are summarized in the following discussion of the general tax principles applicable to the ESPP. This summary is not intended to be exhaustive and, among other considerations, does not describe the deferred compensation provisions of Section 409A of the Internal Revenue Code to the extent an award is subject to and does not satisfy those rules, nor does it describe state, local or international tax consequences. As used below, references to the ESPP also refer to the Amended and Restated ESPP.

The ESPP is intended to qualify as an “employee stock purchase plan” under Section 423 of the Internal Revenue Code. Participant contributions to the ESPP are made on an after-tax basis. That is, a participant’s ESPP contributions are deducted from compensation that is taxable to the participant and for which we are generally entitled to a tax deduction.

Generally, no taxable income is recognized by a participant with respect to either the grant or exercise of his or her option under the ESPP. We will have no tax deduction with respect to either of those events. A participant will generally recognize income (or loss) only upon a sale or disposition of any shares that the participant acquires under the ESPP. The particular tax consequences of a sale of shares acquired under the ESPP depend on whether the participant has held the shares for a “Required Holding Period” before selling or disposing of the shares. The Required Holding Period starts on the date that the participant acquires the shares under the ESPP and ends on the later of: (i) two years after the Enrollment Date of the Offering Period in which the participant acquired the shares; or (ii) one year after the Exercise Date on which the participant acquired the shares.

If the participant holds the shares for the Required Holding Period and then sells the shares at a price in excess of the purchase price paid for the shares, the gain on the sale of the shares will be taxed as ordinary income to the participant to the extent of the lesser of: (i) the amount by which the fair market value of the shares on the Enrollment Date of the Offering Period in which the participant acquired the shares exceeded the purchase price of the shares; or (ii) the gain on the sale of the shares. Any portion of the participant’s gain on the sale of the shares not taxed as ordinary income will be taxed as long-term capital gain. If the participant holds the shares for the Required Holding Period and then sells the shares at a price less than the purchase price paid for the shares, the loss on the sale will be treated as a long-term capital loss to the participant. We will not be entitled to a tax deduction with respect to any shares held by the participant for the Required Holding Period, regardless of whether the shares are eventually sold at a gain or a loss.

The participant has a “Disqualifying Disposition” if the participant disposes of the shares before the participant has held the shares for the Required Holding Period. If the participant sells the shares in a Disqualifying Disposition, the participant will realize ordinary income in an amount equal to the difference between the fair market value of the shares on the Exercise Date on which the participant acquired the shares and the purchase price paid for the shares, and we will generally be entitled to a corresponding tax deduction. In addition, if the participant makes a Disqualifying Disposition of the shares at a price in excess of the fair market value of the shares on the Exercise Date, the participant will realize capital gain in an amount equal to the difference between the selling price of the shares and the fair market value of the shares on the Exercise Date. Alternatively, if the participant makes a Disqualifying Disposition of the shares at a price less than the fair market value of the shares on the Exercise Date, the participant will realize a capital loss in an amount equal to the difference between the fair market value of the shares on the Exercise Date and the selling price of the shares. We will not be entitled to a tax deduction with respect to any capital gain realized by the participant.

Specific Benefits Under the Amended and Restated ESPP

The benefits that will be received by or allocated to eligible employees under the Amended and Restated ESPP cannot be determined at this time because whether an eligible employee will participate, and the amount of contributions set aside to purchase shares of our common stock under the ESPP (subject to the limitations discussed above) as to an eligible employee who elects to participate in the ESPP, is entirely within the discretion of each individual participant.

If the share increase reflected in this Proposal 3 had been in effect in fiscal 2025, we do not expect that the number of shares purchased by participants in the plan during fiscal 2025 would have been materially different than the number of shares that were actually purchased.

For Exercise Periods ending in fiscal 2025, 2024 and 2023, the number of shares of our common stock purchased under the ESPP were 1,966,159 shares, 2,374,439 shares and 2,663,083 shares, respectively. However, because the number of shares purchased under the ESPP in any particular period may change based on any number of variables, including, without limitation, changes in the fair market value of our common stock, the number of eligible employees who elect to participate in the ESPP and the amount of payroll deductions elected by the eligible employees who participate, it is not possible to determine the benefits that will be received by employees if the proposed ESPP amendment is approved by stockholders or how long the additional 8 million shares proposed to be authorized under the ESPP will last, but we expect the additional 8 million shares proposed to be authorized under the Amended and Restated ESPP will last 4 to 6 years based on current practices and other factors.

Aggregate Past Purchases Under the Amended and Restated ESPP

As of September 8, 2025, 40,335,184 shares of our common stock had been purchased under the ESPP. The closing price of our common stock on the Nasdaq Stock Market on September 8, 2025 was $93.29 per share. The following number of shares had been purchased under the ESPP as of that date by the persons and groups identified below:

Registration with the SEC

We intend to file with the SEC a registration on Form S-8 covering the additional shares reserved for issuance under the ESPP in November 2025.

Board Recommendation and Vote Required for Approval

Board Recommendation

Our Board of Directors recommends a vote FOR this Proposal 3 to approve the Amended and Restated ESPP.

The affirmative vote of a majority of the voting power of shares of our Voting Stock (as described in the section entitled “Additional Information—General Information About the Annual Meeting—Who Can Vote”) represented in person or by proxy at the Annual Meeting and entitled to vote on this Proposal 3 is required for approval of the Amended and Restated ESPP. You may vote FOR, AGAINST or ABSTAIN on this proposal. Proxies received by our Board of Directors will be voted FOR this Proposal 3 unless specified otherwise.

Our Board of Directors believes that the Amended and Restated ESPP will promote our interests and our stockholders’ interests and will help us continue to be able to attract, retain and reward persons important to our success.

All of our executive officers would be eligible for awards under the Amended and Restated ESPP and thus have a personal interest in the approval of the Amended and Restated ESPP.