Western Digital CLO sells shares under 10b5-1 plan

Western Digital’s Chief Legal Officer and Corporate Secretary, Cynthia L. Tregillis, reported recent equity transactions in the company’s common stock.

Rhea-AI Filing Summary

Western Digital’s Chief Legal Officer and Corporate Secretary, Cynthia L. Tregillis, reported recent equity transactions in the company’s common stock. She sold a total of 522 shares in open-market transactions at prices of $488.61 and $539.63 per share, under a pre-arranged Rule 10b5-1 trading plan adopted on May 23, 2025. She also had 771 shares withheld to cover tax obligations related to vesting equity awards. In connection with vesting, she exercised dividend equivalent rights into 7.3619 derivative rights and 7 common shares. After these transactions, she directly holds 117,157 shares of Western Digital common stock.

Insider Trade Summary 10b5-1

Exercise and sale activity reported; no spread calculated

Exercise and Sale 5 txns

Insider Tregillis Cynthia L

Role Chief Legal Officer & Corp Sec

Sold 522 shs ($266K)

Approx. gross sale proceeds $266K

Approx. exercise cost $0.00

Type	Security	Shares	Price	Value
Sale	Common Stock	214	$539.63	$115K
Exercise	Dividend Equivalent Rights	7.3619	$0.00	$0.00
Exercise	Common Stock	7	$0.00	$0.00
Exercise Price or Tax Liability	Common Stock	771	$484.28	$373K
Sale	Common Stock	308	$488.61	$150K

Holdings After Transaction: Dividend Equivalent Rights — 311.047 contracts (Direct); Common Stock — 117,157 shares (Direct)

Footnotes (3)

1. F1. 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.
2. F2. 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.
3. F3. Payment of tax obligation by withholding securities incident to the vesting of securities in accordance with Rule 16b-3(e).

Key Figures

Shares sold: 522 shares Sale price (first trade): $488.61 per share Sale price (second trade): $539.63 per share +4 more

7 metrics

Shares sold 522 shares Open-market sales of common stock

Sale price (first trade) $488.61 per share Common stock sale on May 22, 2026

Sale price (second trade) $539.63 per share Common stock sale on May 27, 2026

Shares withheld for taxes 771 shares Tax-withholding disposition on vesting

Dividend equivalent rights exercised 7.3619 rights Converted into common stock on vesting

Shares from derivative exercise 7 shares Non-derivative common stock from M-code exercise

Post-transaction holdings 117,157 shares Directly owned common stock after all transactions

Key Terms

Rule 10b5-1 trading plan, dividend equivalent rights, restricted stock units, Rule 16b-3(e), +1 more

5 terms

Rule 10b5-1 trading plan regulatory

"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."

A Rule 10b5-1 trading plan is a pre-arranged schedule that allows company insiders to buy or sell stock at specific times, even if they have inside information. It helps prevent accusations of unfair trading by making these transactions look planned and transparent, rather than sneaky or illegal.

dividend equivalent rights financial

"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..."

Dividend equivalent rights are promises that mirror the cash payments shareholders get from a company’s profits, but they are paid to holders of certain awards (like stock options or restricted stock units) rather than to actual shares. Think of them as a paycheck top‑up that matches dividends while the award is not yet a real stock, and they matter to investors because they add to employee compensation costs and potential share dilution, affecting company profitability and per‑share value.

restricted stock units financial

"…in connection with the vesting of restricted stock units to which the dividend equivalent rights relate."

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

Rule 16b-3(e) regulatory

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

tax-withholding disposition financial

"Payment of exercise price or tax liability by delivering securities"

A tax-withholding disposition is an event or transaction—such as selling or transferring securities, exercising options, or receiving compensation—that triggers a requirement to hold back part of the payment and remit it to tax authorities. It matters to investors because it reduces the cash they receive immediately and can change the timing and amount of taxable income, like a cashier taking a portion of your sale proceeds to pay taxes before you get the rest.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What insider transactions did Western Digital (WDC) report for Cynthia Tregillis?

Cynthia L. Tregillis reported selling 522 Western Digital common shares in open-market transactions, plus 771 shares withheld for taxes and small exercises of dividend equivalent rights tied to vested equity awards, leaving her with 117,157 directly held shares.

How many Western Digital shares does Cynthia Tregillis own after this Form 4?

After the reported trades and tax-withholding events, Cynthia L. Tregillis directly owns 117,157 shares of Western Digital common stock, according to the Form 4, reflecting her remaining equity stake following the modest sales and vesting-related share movements.

Were Cynthia Tregillis’s Western Digital share sales under a Rule 10b5-1 plan?

Yes. A footnote states the sales disclosed in this Form 4 were effected under a Rule 10b5-1 trading plan adopted by Cynthia L. Tregillis on May 23, 2025, indicating the dispositions were pre-arranged rather than timed discretionarily.

What were the sale prices for Cynthia Tregillis’s Western Digital (WDC) shares?

She sold Western Digital common stock at per-share prices of $488.61 and $539.63. These transactions totaled 522 shares and were reported as open-market or private sales, executed pursuant to her previously adopted Rule 10b5-1 trading plan.

Why were 771 Western Digital shares disposed of for Cynthia Tregillis?

The 771-share disposition is described as payment of tax obligations by withholding securities when equity awards vested. This tax-withholding event is coded as an F transaction and is not an open-market sale, but an automatic mechanism to satisfy tax liabilities.

What are dividend equivalent rights mentioned in the Western Digital Form 4?

Dividend equivalent rights credited to Cynthia Tregillis were converted into 7.3619 derivative rights and paid in common stock on a one-for-one basis as related restricted stock units vested, with a small cash amount used to settle a fractional right.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 05/27/2026 - 06:41 PM Learn about SEC filing dates

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 CALIFORNIA 95119

(City) (State) (Zip)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/22/2026

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

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

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

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	05/22/2026		S(1)		308	D	$488.61	118,135	D
Common Stock	05/25/2026		M		7(2)	A	$0.0	118,142	D
Common Stock	05/25/2026		F		771(3)	D	$484.28	117,371	D
Common Stock	05/27/2026		S(1)		214	D	$539.63	117,157	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	(2)	05/25/2026		M			7.3619	(2)	(2)	Common Stock	7.3619	$0.0	311.047	D

Explanation of Responses:

1. 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.

2. 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.

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

	By: /s/ Sandra Garcia Attorney-in-Fact For: Cynthia Tregillis	05/27/2026
	** 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.
* Form 4: SEC 1474 (03-26)