[Form 4] Western Digital Corp. Insider Trading Activity

Rhea-AI Filing Summary

Cynthia Tregillis, Chief Legal Officer and Corporate Secretary of Western Digital Corp (WDC), reported insider transactions on 08/21/2025 and 08/22/2025. On 08/21/2025 dividend equivalent rights were converted into common stock on a one-for-one basis and paid in shares, resulting in a reported beneficial ownership of 153,846 shares following that transaction. Also on 08/21/2025, 4,428 shares were withheld to satisfy tax obligations, reducing ownership to 149,418. On 08/22/2025 the reporting person sold 14,067 shares at an average price of $74.78 under a Rule 10b5-1 trading plan adopted May 23, 2025, leaving 135,351 shares beneficially owned. The Form 4 was signed on behalf of the reporting person by an attorney-in-fact on 08/25/2025.

Positive

• Transactions were disclosed promptly on a Form 4 with clear dates and amounts
• Sale executed under a Rule 10b5-1 plan, indicating pre-arranged compliance with insider trading rules
• Dividend equivalent rights converted to shares on a one-for-one basis, shown in the filing

Negative

• Net holdings decreased from 153,846 shares to 135,351 shares after tax withholding and sale
• Sale of 14,067 shares produced cash proceeds at $74.78 which reduced insider ownership

Insights

Corporate Governance Expert

TL;DR: Routine reporting of vested dividend equivalents, tax-withholding, and a pre-established 10b5-1 sale; no unexplained or unusual disclosures.

The Form 4 documents a standard sequence: dividend equivalent rights converted to shares upon RSU vesting, shares withheld to cover tax obligations, and a subsequent sale executed under a Rule 10b5-1 plan adopted May 23, 2025. These actions are typical for executive compensation monetization and tax settlement. The use of a 10b5-1 plan indicates the sale was pre-authorized which helps manage insider trading compliance risk. The remaining beneficial ownership after the transactions is explicitly stated as 135,351 shares.

Securities Analyst

TL;DR: Transactions are operationally driven by vesting and tax mechanics; sale quantity and prices are disclosed and modest relative to routine insider activity.

The report discloses a conversion of dividend equivalent rights to common stock (one-for-one), a tax-withholding event of 4,428 shares at an implied withholding price of $74.66, and a sale of 14,067 shares at $74.78. The explicit prices and share counts allow straightforward calculation of cash proceeds and net holdings changes. There is no indication of material change to ownership percentages or control from the disclosed transactions.

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
Estimated average burden
hours per response:			0.5

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

X

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)
08/21/2025

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
Common Stock	08/21/2025		M		18(1)	A	$0.0	153,846	D
Common Stock	08/21/2025		F		4,428(2)	D	$74.66	149,418	D
Common Stock	08/22/2025		S(3)		14,067	D	$74.78	135,351	D

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)	08/21/2025		M			18.9863	(1)	(1)	Common Stock	18.9863	$0.0	186.2484	D

Explanation of Responses:

1. The dividend equivalent rights were converted into, and paid in the form of, shares of the Issuer's common stock on a one-for-one basis in connection with the vesting of restricted stock units to which the dividend equivalent rights relate. A cash amount was also paid to the holder to settle a fractional dividend equivalent right.

2. Payment of tax obligation by withholding securities incident to the vesting of securities in accordance with Rule 16b-3(e).

3. The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on May 23, 2025.

	By: /s/ Sandra Garcia Attorney-in-Fact For: Cynthia Tregillis	08/25/2025
	** 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 insider transactions did Cynthia Tregillis report for WDC?

Answer: She reported conversion of dividend equivalent rights into shares on 08/21/2025, withholding of 4,428 shares for taxes, and a sale of 14,067 shares on 08/22/2025.

How many WDC shares does Cynthia Tregillis beneficially own after these transactions?

Answer: The Form 4 reports 135,351 shares beneficially owned following the transactions.

At what price were the WDC shares sold by the reporting person?

Answer: The sale on 08/22/2025 was reported at an average price of $74.78 per share.

Why were some shares withheld in the filing?

Answer: 4,428 shares were withheld to satisfy the reporting person’s tax obligation in connection with vesting, per the filing.

Was the sale pre-planned under insider trading rules?

Answer: Yes; the filing states the sales were effected pursuant to a Rule 10b5-1 trading plan adopted on May 23, 2025.