Western Digital (WDC)

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-09-17 10b5-1 Pre-arranged Plan: No --- Issuer --- Name: WESTERN DIGITAL CORP (WDC) CIK: 0000106040 --- Reporting Owner --- Name: Tregillis Cynthia L CIK: 0002057088 Role: Officer (Chief Legal Officer & Corp Sec) --- Derivative Transactions --- [Transaction #1] Security: Dividend Equivalent Rights Date: 2026-09-17 | Code: A (Grant or award) Shares: +27.38 | Price: $0.00 Shares Owned After: 297.8619 | Ownership: D (Direct) Footnotes: [F1] The dividend equivalent rights accrued on previously awarded restricted stock units (RSUs) which vest proportionately with the RSUs to which they relate. Each dividend equivalent right represents a contingent right to receive one share of the Issuer's common stock or the cash value thereof. [F1] The dividend equivalent rights accrued on previously awarded restricted stock units (RSUs) which vest proportionately with the RSUs to which they relate. Each dividend equivalent right represents a contingent right to receive one share of the Issuer's common stock or the cash value thereof. [F1] The dividend equivalent rights accrued on previously awarded restricted stock units (RSUs) which vest proportionately with the RSUs to which they relate. Each dividend equivalent right represents a contingent right to receive one share of the Issuer's common stock or the cash value thereof. --- Footnotes (Complete Index) --- F1: The dividend equivalent rights accrued on previously awarded restricted stock units (RSUs) which vest proportionately with the RSUs to which they relate. Each dividend equivalent right represents a contingent right to receive one share of the Issuer's common stock or the cash value thereof. --- Signature --- /s/ By: /s/ Sandra Garcia Attorney-in-Fact For: Cynthia Tregillis (2026-09-21)