Insider Cynthia Tregillis sells 9,324 shares

Cynthia Lock Tregillis reported open‑market dispositions of Common Stock under Rule 144.

Rhea-AI Filing Summary

Cynthia Lock Tregillis reported open‑market dispositions of Common Stock under Rule 144. The filing lists multiple sales in 2026, including 9,324 shares on 03/04/2026 for $2,501,381.80, and smaller transactions such as 308 shares on 05/21/2026 for $150,491.88. The shares are described as Restricted Stock.

Key Figures

Sale — 03/04/2026: 9,324 shares Proceeds — 03/04/2026: $2,501,381.80 Sale — 05/21/2026: 308 shares +4 more

7 metrics

Sale — 03/04/2026 9,324 shares Sale dated <date>03/04/2026</date>

Proceeds — 03/04/2026 $2,501,381.80 Gross proceeds for 9,324 shares on <date>03/04/2026</date>

Sale — 05/21/2026 308 shares Sale dated <date>05/21/2026</date>

Proceeds — 05/21/2026 $150,491.88 Gross proceeds for 308 shares on <date>05/21/2026</date>

Sale — 04/21/2026 363 shares Sale dated <date>04/21/2026</date>

Proceeds — 04/21/2026 $136,883.67 Gross proceeds for 363 shares on <date>04/21/2026</date>

Sale — 02/24/2026 308 shares Sale dated <date>02/24/2026</date>

Key Terms

Form 144, Restricted Stock, Gross proceeds

3 terms

Form 144 regulatory

"The title and context indicate a Rule 144 notice of proposed sale of restricted securities"

Form 144 is a document that investors must file with the government when they plan to sell a large number of shares of a company's stock. It helps ensure transparency so everyone knows how many shares are being sold and when, which can impact the stock's price.

Restricted Stock financial

"Securities To Be Sold: Common | 05/21/2026 | Restricted Stock"

Shares granted to an individual that carry limits on transfer or sale until certain conditions are met, such as staying with the company for a set time or hitting performance targets. Think of them as a locked gift that gradually opens; for investors they matter because they affect how many shares may enter the market later, signal management incentives and potential dilution, and reveal confidence in future company performance.

Gross proceeds financial

"Entries list share counts followed by dollar amounts (e.g., 9,324 | 2501381.80)"

The total amount of cash a company receives from a financing event or sale before any fees, expenses, taxes or deductions are taken out. Investors watch gross proceeds because it shows the raw scale of new capital being raised—think of it as the paycheck amount before withholdings—which helps assess how much funding is available for operations, growth, debt payoff or how much shareholder dilution might occur once costs are removed.

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

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Accepted by SEC EDGAR 05/22/2026 - 04:26 PM EDT Learn about SEC filing dates

Form 144 Filer Information	UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Form 144 NOTICE OF PROPOSED SALE OF SECURITIES PURSUANT TO RULE 144 UNDER THE SECURITIES ACT OF 1933
FORM 144

144: Filer Information

Filer CIK	0002057088
Filer CCC	XXXXXXXX
Is this a LIVE or TEST Filing?	LIVE TEST
Submission Contact Information
Name
Phone
E-Mail Address

144: Issuer Information

Name of Issuer	WESTERN DIGITAL CORPORATION
SEC File Number	001-08703
Address of Issuer	5601 Great Oaks Parkway San Jose CALIFORNIA 95119
Phone	(408) 717-6000
Name of Person for Whose Account the Securities are To Be Sold	CYNTHIA LOCK TREGILLIS
See the definition of "person" in paragraph (a) of Rule 144. Information is to be given not only as to the person for whose account the securities are to be sold but also as to all other persons included in that definition. In addition, information shall be given as to sales by all persons whose sales are required by paragraph (e) of Rule 144 to be aggregated with sales for the account of the person filing this notice.
Relationship to Issuer	Officer

144: Securities Information

Title of the Class of Securities To Be Sold	Name and Address of the Broker	Number of Shares or Other Units To Be Sold	Aggregate Market Value	Number of Shares or Other Units Outstanding	Approximate Date of Sale	Name the Securities Exchange
Common	Morgan Stanley Smith Barney LLC Executive Financial Services 1 New York Plaza 8th Floor New York NY 10004	308	150491.88	344682131	05/22/2026	NASDAQ

Furnish the following information with respect to the acquisition of the securities to be sold and with respect to the payment of all or any part of the purchase price or other consideration therefor:

144: Securities To Be Sold

Title of the Class	Date you Acquired	Nature of Acquisition Transaction	Name of Person from Whom Acquired	Is this a Gift?	Date Donor Acquired	Amount of Securities Acquired	Date of Payment	Nature of Payment *
Common	05/21/2026	Restricted Stock	ISSUER			308	05/21/2026	Not Applicable

* If the securities were purchased and full payment therefor was not made in cash at the time of purchase, explain in the table or in a note thereto the nature of the consideration given. If the consideration consisted of any note or other obligation, or if payment was made in installments describe the arrangement and state when the note or other obligation was discharged in full or the last installment paid.

Furnish the following information as to all securities of the issuer sold during the past 3 months by the person for whose account the securities are to be sold.

144: Securities Sold During The Past 3 Months

Name and Address of Seller	Title of Securities Sold	Date of Sale	Amount of Securities Sold	Gross Proceeds
CYNTHIA LOCK TREGILLIS 5601 Great Oaks Parkway San Jose CA 95119	Common	05/21/2026	106	48640.22
CYNTHIA LOCK TREGILLIS 5601 Great Oaks Parkway San Jose CA 95119	Common	04/21/2026	363	136883.67
CYNTHIA LOCK TREGILLIS 5601 Great Oaks Parkway San Jose CA 95119	Common	03/04/2026	9324	2501381.80
CYNTHIA LOCK TREGILLIS 5601 Great Oaks Parkway San Jose CA 95119	Common	02/26/2026	214	61227.54
CYNTHIA LOCK TREGILLIS 5601 Great Oaks Parkway San Jose CA 95119	Common	02/24/2026	308	86763.60
CYNTHIA LOCK TREGILLIS 5601 Great Oaks Parkway San Jose CA 95119	Common	02/23/2026	130	36897.90

144: Remarks and Signature

Remarks
Date of Notice	05/22/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	05/23/2025
ATTENTION:
The person for whose account the securities to which this notice relates are to be sold hereby represents by signing this notice that he does not know any material adverse information in regard to the current and prospective operations of the Issuer of the securities to be sold which has not been publicly disclosed. If such person has adopted a written trading plan or given trading instructions to satisfy Rule 10b5-1 under the Exchange Act, by signing the form and indicating the date that the plan was adopted or the instruction given, that person makes such representation as of the plan adoption or instruction date.
Signature	/s/ Cynthia Lock Tregillis
ATTENTION: Intentional misstatements or omission of facts constitute Federal Criminal Violations (See 18 U.S.C. 1001)