Western Digital (WDC) CLO Tregillis records small 10b5-1 share sale

Rhea-AI Filing Summary

WESTERN DIGITAL CORP Chief Legal Officer Cynthia L. Tregillis reported multiple equity transactions involving the company’s common stock. She sold 363 shares in an open-market trade at $377.09 per share, under a pre-arranged Rule 10b5-1 trading plan.

On the prior day, 1,308 shares were withheld to cover tax obligations tied to vesting, and dividend equivalent rights were exercised and converted on a one-for-one basis into 12.4923 shares of common stock. After these transactions, she directly holds 120,023 shares, indicating that the sale represents a relatively small portion of her overall position.

Insights

Equity compensation & governance analyst

Routine compensation-related activity with a small, pre-planned stock sale.

Cynthia L. Tregillis, Chief Legal Officer of WESTERN DIGITAL CORP, reported several transactions. A key event is an open-market sale of 363 common shares at $377.09 per share, executed under a Rule 10b5-1 trading plan adopted on May 23, 2025.

Other movements are mechanistic: 1,308 shares were withheld to satisfy tax obligations linked to vesting, and dividend equivalent rights were exercised and converted into 12.4923 common shares. These are standard equity-compensation mechanics rather than discretionary trades.

Following the transactions, Tregillis directly holds 120,023 common shares. Given the small number of shares sold relative to this holding and the pre-planned nature of the sale, the filing looks like routine portfolio and tax management rather than a significant change in insider sentiment.

Insider Trade Summary 10b5-1

Net Seller: 363 shares ($136,884)

Net Sell 4 txns

Insider Tregillis Cynthia L

Role Chief Legal Officer & Corp Sec

Sold 363 shs ($137K)

Type	Security	Shares	Price	Value
Sale	Common Stock	363	$377.09	$137K
Exercise	Dividend Equivalent Rights	12.492	$0.00	--
Exercise	Common Stock	12	$0.00	--
Tax Withholding	Common Stock	1,308	$374.11	$489K

Holdings After Transaction: Common Stock — 120,023 shares (Direct, null); Dividend Equivalent Rights — 332.628 shares (Direct, null)

Footnotes (1)

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

Key Figures

Open-market sale: 363 shares at $377.09 Tax-withholding shares: 1,308 shares at $374.11 Post-transaction holdings: 120,023 shares +2 more

5 metrics

Open-market sale 363 shares at $377.09 Common Stock sale on April 21, 2026

Tax-withholding shares 1,308 shares at $374.11 Withheld for tax obligations on April 20, 2026

Post-transaction holdings 120,023 shares Common Stock directly held after April 21, 2026

Dividend equivalent conversion 12.4923 rights to 12.4923 shares Converted to common stock on April 20, 2026

Derivative transactions 1 derivative transaction Exercise/conversion classified in transaction summary

Key Terms

Dividend Equivalent Rights, Rule 10b5-1 trading plan, restricted stock units, Rule 16b-3(e), +1 more

5 terms

Dividend Equivalent Rights financial

"The dividend equivalent rights were converted into, and paid in the form of, shares of the Issuer's common stock"

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.

Rule 10b5-1 trading plan regulatory

"The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan"

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.

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

"transaction_action": "tax-withholding disposition""

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.

Form 4 Insider Transactions: What Each Field Means →

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)
04/20/2026

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	04/20/2026		M		12(1)	A	$0.0	121,694	D
Common Stock	04/20/2026		F		1,308(2)	D	$374.11	120,386	D
Common Stock	04/21/2026		S(3)		363	D	$377.09	120,023	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)	04/20/2026		M			12.4923	(1)	(1)	Common Stock	12.4923	$0.0	332.6277	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	04/22/2026
	** 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)

FAQ

What insider transactions did WDC’s Cynthia L. Tregillis report in this Form 4?

Cynthia L. Tregillis reported a small open-market sale and compensation-related share movements. She sold 363 Western Digital common shares, had 1,308 shares withheld for taxes, and exercised dividend equivalent rights converting into 12.4923 common shares, all while remaining a significant direct shareholder.

How many Western Digital (WDC) shares did Cynthia L. Tregillis sell and at what price?

She sold 363 Western Digital common shares at $377.09 per share. The transaction was classified as an open-market sale and was executed pursuant to a Rule 10b5-1 trading plan, indicating it was pre-arranged rather than a purely discretionary market-timing decision.

How many WDC shares does Cynthia L. Tregillis hold after these transactions?

After the reported transactions, Tregillis directly holds 120,023 Western Digital shares. This post-transaction balance shows that the 363 shares sold represent only a small fraction of her overall equity position in the company’s common stock.

What was the purpose of the 1,308 Western Digital shares classified as a tax-withholding disposition?

The 1,308 shares were withheld to satisfy tax obligations on vesting equity. The filing describes this as payment of tax obligations by withholding securities, carried out in accordance with Rule 16b-3(e), which typically governs insider transactions tied to compensation plans.

What are the dividend equivalent rights mentioned in the WDC Form 4 filing?

The dividend equivalent rights were converted into Western Digital common stock. They converted on a one-for-one basis into 12.4923 common shares in connection with the vesting of related restricted stock units, with a fractional dividend equivalent right settled in cash for the holder.