[Form 4] WESTERN DIGITAL CORP Insider Trading Activity

Rhea-AI Filing Summary

Matthew E. Massengill, a director of Western Digital Corporation (WDC), was issued 26.0182 shares as dividend equivalent rights tied to previously awarded restricted stock units (RSUs). The filing reports the dividend equivalents accrued on RSUs and that they vest proportionately with the underlying RSUs; each dividend equivalent represents a contingent right to receive one share of common stock or its cash value. The Form 4 reports the transaction date as 09/18/2025 and is signed by an attorney-in-fact on 09/22/2025.

Positive

• 26.0182 shares issued as dividend equivalents, increasing the reporting person's beneficial ownership as disclosed
• Clear disclosure that dividend equivalents vest proportionately with underlying RSUs and may convert to either one share each or cash

Negative

• None.

Insights

Securities Analyst

TL;DR: Director received 26.0182 shares as dividend equivalents on RSUs; routine insider compensation-related transaction with limited market impact.

The Form 4 documents a non-derivative issuance of 26.0182 common shares as dividend equivalent rights that vest with previously granted RSUs. This transaction reflects standard equity compensation mechanics rather than an open-market purchase or sale. Because the shares are dividend equivalents tied to RSU vesting, they increase the reporting person’s beneficial ownership by the stated amount but do not indicate discretionary trading by the insider. Impact on shareholder dilution is likely immaterial given the small absolute share amount disclosed.

Corporate Governance Expert

TL;DR: Filing shows routine compensation administration; disclosure meets Section 16 reporting requirements.

The disclosure clarifies the nature of the award: dividend equivalent rights that convert to one share each (or cash) and vest pro rata with underlying RSUs. The Form 4 is properly executed by an attorney-in-fact and specifies the reporting person’s role as a director. This is a standard post-grant administrative reporting event and does not signal a change in board membership, compensation policy, or control structure.

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

MASSENGILL MATTHEW E

(Last) (First) (Middle)

C/O WESTERN DIGITAL CORPORATION

5601 GREAT OAKS PARKWAY

(Street)

SAN JOSE CA 95119

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
WESTERN DIGITAL CORP [ WDC ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
09/18/2025

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Dividend Equivalent Rights	(1)	09/18/2025		A		26.0182		(1)	(1)	Common Stock	26.0182	$0.0	72.1612	D

Explanation of Responses:

1. The dividend equivalent rights accrued on previously awarded restricted stock units (RSUs) which vest proportionately with the RSUs to which they relate. Each dividend equivalent right represents a contingent right to receive one share of the Issuer's common stock or the cash value thereof.

	By: /s/ Sandra Garcia Attorney-in-Fact For: Matthew E. Massengill	09/22/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What transaction did Matthew E. Massengill report on Form 4 for WDC?

He reported the accrual and issuance of 26.0182 dividend equivalent rights tied to previously awarded RSUs, dated 09/18/2025.

What are the dividend equivalent rights described in the WDC Form 4?

They are contingent rights that vest with the RSUs and represent the right to receive one share of common stock or the cash value per dividend equivalent.

When was the Form 4 for this transaction signed?

The Form 4 was executed by an attorney-in-fact and signed on 09/22/2025.

Does the Form 4 indicate a purchase or sale of WDC common stock?

No. The filing reports issuance of dividend equivalent rights related to RSUs, not an open-market purchase or sale.

What is the reporting person's relationship to WDC?

The reporting person, Matthew E. Massengill, is identified as a Director of Western Digital Corporation.