[Form 4] WESTERN DIGITAL CORP Insider Trading Activity

Rhea-AI Filing Summary

Cynthia L. Tregillis, Chief Legal Officer and Corporate Secretary of Western Digital Corporation (WDC), reported a change in beneficial ownership. The Form 4 discloses a transaction dated 09/18/2025 reflecting the accrual and acquisition of 118.2565 dividend equivalent rights tied to previously awarded restricted stock units (RSUs); each right converts to one share or its cash value and vests proportionately with the related RSUs. Following the reported transaction, the filing shows 300.0616 shares beneficially owned. The Form 4 was executed by an attorney-in-fact on 09/22/2025 and includes the issuer address and reporting-person role.

Positive

• Transparent disclosure: The Form 4 reports the RSU dividend-equivalent accrual and conversion, supporting insider-reporting compliance.
• Equity compensation settled through dividend equivalents: 118.2565 share-equivalents added, showing compensation mechanics functioning as described.

Negative

• None.

Insights

Financial Analyst

TL;DR: A routine accrual-conversion of RSU dividend equivalents increased an insider's stake by ~118 shares; impact on valuation is negligible.

This filing documents the conversion of accrued dividend equivalent rights associated with existing RSUs into equity (or cash value), adding 118.2565 share-equivalents to Cynthia Tregillis's holdings, for a total reported beneficial ownership of 300.0616 shares. The disclosure is procedural and does not report options exercised, cash purchases, sales, or other derivative activity. For investors, this is primarily a compliance disclosure showing dilution-neutral compensation settlement tied to prior equity awards rather than an active market trade.

Corporate Governance Expert

TL;DR: The Form 4 is a standard insider reporting of RSU-related dividend equivalents; it confirms governance transparency and award vesting mechanics.

The Form 4 specifies that dividend equivalent rights accrued on previously awarded RSUs vest proportionately and convert into common stock or cash. The filing identifies the reporting person’s role as Chief Legal Officer & Corporate Secretary, indicating senior management participation in the company's equity compensation program. The document is signed by an attorney-in-fact, consistent with common administrative practice for timely reporting of equity settlements tied to compensation arrangements.

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

OMB APPROVAL

OMB Number:			3235-0287
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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^*

Tregillis Cynthia L

(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)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Legal Officer & Corp Sec

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		118.2565		(1)	(1)	Common Stock	118.2565	$0.0	300.0616	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: Cynthia Tregillis	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 did the Form 4 filed for WDC report?

The Form 4 reports the acquisition of 118.2565 dividend equivalent rights tied to previously awarded RSUs, resulting in 300.0616 shares beneficially owned.

Who is the reporting person on this Form 4 for WDC?

The reporting person is Cynthia L. Tregillis, identified as Chief Legal Officer & Corporate Secretary of Western Digital Corporation.

When was the transaction dated and when was the Form 4 signed?

The transaction date is 09/18/2025, and the Form 4 was signed by an attorney-in-fact on 09/22/2025.

What are dividend equivalent rights as described in the filing?

The filing states each dividend equivalent right represents a contingent right to receive one share of common stock or the cash value thereof and vests proportionately with the related RSUs.

Does the Form 4 report any sales or option exercises?

No. The filing reports only accrual/conversion of dividend equivalent rights tied to RSUs; it does not disclose sales or option exercises.