Western Digital officer plans $481,708 stock sale

WESTERN DIGITAL CORPORATION (WDC) is the issuer for which officer Cynthia Lock Tregillis has filed a Form 144 notice of proposed sale of restricted common stock.

Rhea-AI Filing Summary

WESTERN DIGITAL CORPORATION (WDC) is the issuer for which officer Cynthia Lock Tregillis has filed a Form 144 notice of proposed sale of restricted common stock. The notice indicates an intended sale of 1,007 shares of Western Digital common stock through Morgan Stanley Smith Barney LLC Executive Financial Services, with an aggregate market value of $481,708.52 and a proposed sale date around August 27, 2026 on NASDAQ. The securities are described as restricted stock acquired from the issuer. Over the prior three months, Tregillis reported multiple sales of Western Digital common shares, including 432 shares for $235,699.20 on June 5, 2026; 808 shares for $427,941.04 on July 21, 2026; and several August 2026 transactions of 235, 684, and 476 shares with reported proceeds of $112,158.45, $305,180.28, and $214,571.28, respectively.

Key Figures

Shares proposed to be sold: 1,007 shares of common stock Aggregate market value of proposed sale: $481,708.52 Sale on 06/05/2026: 432 shares for $235,699.20 +4 more

7 metrics

Shares proposed to be sold 1,007 shares of common stock Proposed sale under Rule 144 with securities information tied to 08/27/2026

Aggregate market value of proposed sale $481,708.52 Value associated with 1,007 Western Digital common shares in the Form 144 securities information

Sale on 06/05/2026 432 shares for $235,699.20 Common stock sold during the past 3 months by Cynthia Lock Tregillis

Sale on 07/21/2026 808 shares for $427,941.04 Common stock sale listed in the past 3 months section

Sale on 08/21/2026 235 shares for $112,158.45 One of several August 2026 common stock sales reported

Sale on 08/24/2026 684 shares for $305,180.28 Common stock sale reported in the past 3 months section

Sale on 08/26/2026 476 shares for $214,571.28 Most recent common stock sale reported prior to the proposed new sale

Key Terms

Rule 144, restricted stock, Form 144, aggregate market value, +1 more

5 terms

Rule 144 regulatory

"See the definition of "person" in paragraph (a) of Rule 144."

Rule 144 is a U.S. securities regulation that sets conditions under which restricted or insider-held shares can be legally resold to the public, such as required holding periods, availability of public information, limits on how much can be sold at once, and certain filing requirements. For investors it matters because it determines when previously locked-up shares can enter the market — like a release valve that can increase supply, affect share price, and signal insider intent.

restricted stock financial

"Common | 08/26/2026 | Restricted Stock | ISSUER"

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.

Form 144 regulatory

"144: Filer Information"

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.

aggregate market value financial

"Common | ... | 1007 | 481708.52 | 360540944 | 08/27/2026"

Aggregate market value is the combined price you would pay to buy all outstanding shares of a company or all companies in a group at current market prices — essentially the sum of each stock’s market capitalization. It matters to investors because it shows the overall size and weight of an investment or sector (like the total cost to buy every piece of a puzzle), helps compare scale across companies or markets, and influences index composition and risk exposure.

issuer regulatory

"Restricted Stock | ISSUER"

FAQ

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

What does Western Digital (WDC) disclose in this Form 144 filing?

The filing reports that Cynthia Lock Tregillis, an officer of Western Digital, has notified of a proposed sale of 1,007 shares of Western Digital common stock under Rule 144, with an indicated aggregate market value of $481,708.52 and a proposed sale date of August 27, 2026.

How many Western Digital (WDC) shares are proposed to be sold under this Form 144?

The notice covers a proposed sale of 1,007 shares of Western Digital common stock. These shares are described as restricted stock acquired from the issuer and are expected to be sold through Morgan Stanley Smith Barney LLC Executive Financial Services on NASDAQ.

What is the reported value of the Western Digital (WDC) shares in this Form 144?

The proposed sale of 1,007 shares of Western Digital common stock has a reported aggregate market value of $481,708.52. This valuation appears in the securities information section associated with the planned NASDAQ sale dated August 27, 2026.

What type of Western Digital (WDC) securities is Cynthia Lock Tregillis planning to sell?

The Form 144 indicates that the securities are Western Digital common stock classified as restricted stock, acquired from the issuer. The filing lists a proposed sale of 1,007 restricted shares through Morgan Stanley Smith Barney LLC Executive Financial Services.

What Western Digital (WDC) share sales has Cynthia Lock Tregillis reported in the past three months?

Over the past three months, Tregillis reported several sales of Western Digital common stock, including 432 shares for $235,699.20 on June 5, 2026; 808 shares for $427,941.04 on July 21, 2026; and August 2026 sales of 235, 684, and 476 shares for $112,158.45, $305,180.28, and $214,571.28, respectively.

Who is the broker handling the proposed Western Digital (WDC) share sale in this Form 144?

The proposed sale of 1,007 Western Digital common shares is listed as being handled by Morgan Stanley Smith Barney LLC Executive Financial Services, located at 1 New York Plaza, 8th Floor, New York, NY 10004, with the shares to be sold on NASDAQ.

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

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Available on EDGAR 08/27/2026 - 04:03 PM EDT Accepted by SEC EDGAR 08/27/2026 - 04:03 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	1007	481708.52	360540944	08/27/2026	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	08/26/2026	Restricted Stock	ISSUER			1007	08/26/2026	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	08/26/2026	476	214571.28
CYNTHIA LOCK TREGILLIS 5601 Great Oaks Parkway San Jose CA 95119	Common	08/24/2026	684	305180.28
CYNTHIA LOCK TREGILLIS 5601 Great Oaks Parkway San Jose CA 95119	Common	08/21/2026	235	112158.45
CYNTHIA LOCK TREGILLIS 5601 Great Oaks Parkway San Jose CA 95119	Common	07/21/2026	808	427941.04
CYNTHIA LOCK TREGILLIS 5601 Great Oaks Parkway San Jose CA 95119	Common	06/05/2026	432	235699.20

144: Remarks and Signature

Remarks
Date of Notice	08/27/2026
Date of Plan Adoption or Giving of Instruction, If Relying on Rule 10b5-1	03/06/2026
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)