Cynthia L. Tregillis - 03 Mar 2026 Form 4 Insider Report for WESTERN DIGITAL CORP (WDC)

Role
Chief Legal Officer & Corp Sec
Signature
By: /s/ Sandra Garcia Attorney-in-Fact For: Cynthia Tregillis
Issuer symbol
WDC
Transactions as of
03 Mar 2026
Net transactions value
-$2,501,382
Form type
4
Filing time
05 Mar 2026, 19:55:20 UTC
Previous filing
27 Feb 2026
SEC
View on sec.gov

Reporting Owners (1)

Name Relationship Address Signature Signature date CIK
Tregillis Cynthia L Chief Legal Officer & Corp Sec C/O WESTERN DIGITAL CORPORATION, 5601 GREAT OAKS PARKWAY, SAN JOSE By: /s/ Sandra Garcia Attorney-in-Fact For: Cynthia Tregillis 05 Mar 2026 0002057088

Transactions Table

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Ownership Footnotes
transaction WDC Common Stock Options Exercise +23 +0.02% $0.000000* 133,804 03 Mar 2026 Direct F1
transaction WDC Common Stock Tax liability -2,798 -2.1% $250.61* 131,006 03 Mar 2026 Direct F2
transaction WDC Common Stock Sale $200,396 -777 -0.59% $257.91 130,229 04 Mar 2026 Direct F3
transaction WDC Common Stock Sale $2,300,986 -8,547 -6.6% $269.22 121,682 04 Mar 2026 Direct F4

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type Sym Class Transaction Value $ Shares Change % * Price $ Shares After Date Underlying Class Amount Exercise Price Ownership Footnotes
transaction WDC Dividend Equivalent Rights Options Exercise -24 -7.3% $0.000000* 304 03 Mar 2026 Common Stock 24 Direct F1
* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Buy Plan / Sale Plan: These are also open market purchases/sales of shares, but in this case the transaction is part of a trading plan. Rule 10b5-1 allows insiders to setup a trading plan to buy/sell stocks over a certain period of time. Since the purchases/sales are predetermined, this protects the insiders from violating insider trading law.

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).

Explanation of Responses:

Id Content
F1 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.
F2 Payment of tax obligation by withholding securities incident to the vesting of securities in accordance with Rule 16b-3(e).
F3 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.
F4 Represents the weighted average sale price per share. These shares were sold in multiple transactions at prices ranging from a low of $269.17 to a high of $269.2201. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price.