WESTERN DIGITAL CORP (WDC) · Insider Trading (Form 4) SEC Filing

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-07-20 10b5-1 Pre-arranged Plan: Yes --- Issuer --- Name: WESTERN DIGITAL CORP (WDC) CIK: 0000106040 --- Reporting Owner --- Name: Tregillis Cynthia L CIK: 0002057088 Role: Officer (Chief Legal Officer & Corp Sec) --- Non-Derivative Transactions --- [Transaction #1] Security: Common Stock Date: 2026-07-20 | Code: M (Exercise of derivative) Shares: +13 | Price: $0.00 Shares Owned After: 116,656 | Ownership: D (Direct) Footnotes: [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. [Transaction #2] Security: Common Stock Date: 2026-07-20 | Code: F (Payment of exercise/tax) Shares: -1,309 | Price: $487.42 Total Value: $638,032.78 Shares Owned After: 115,347 | Ownership: D (Direct) Footnotes: [F2] Payment of tax obligation by withholding securities incident to the vesting of securities in accordance with Rule 16b-3(e). [Transaction #3] Security: Common Stock Date: 2026-07-21 | Code: S (Open market sale) Shares: -808 | Price: $529.63 Total Value: $427,941.04 Shares Owned After: 114,539 | Ownership: D (Direct) Footnotes: [F3] The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on March 6, 2026. --- Derivative Transactions --- [Transaction #1] Security: Dividend Equivalent Rights Date: 2026-07-20 | Code: M (Exercise of derivative) Shares: -13.1971 | Price: $0.00 Shares Owned After: 309.804 | Ownership: D (Direct) Footnotes: [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. [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. [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. --- Footnotes (Complete Index) --- 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 March 6, 2026. --- Signature --- /s/ By: /s/ Sandra Garcia Attorney-in-Fact For: Cynthia Tregillis (2026-07-21)