Western Digital (WDC)

=== SEC Form 4 — Statement of Changes in Beneficial Ownership === Document Type: 4 Period of Report: 2026-08-25 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: 2026-08-25 | Code: M (Exercise of derivative) Shares: +7 | Price: $0.00 Shares Owned After: 112,153 | 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: 2026-08-25 | Code: F (Payment of exercise/tax) Shares: -771 | Price: $450.75 Total Value: $347,528.25 Shares Owned After: 111,382 | 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: 2026-08-25 | Code: A (Grant or award) Shares: +3,878 | Price: $0.00 Shares Owned After: 115,260 | Ownership: D (Direct) Footnotes: [F3] Represents the grant of restricted stock units to the Reporting Person. Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock. [Transaction #4] Security: Common Stock Date: 2026-08-26 | Code: S (Open market sale) Shares: -476 | Price: $450.78 Total Value: $214,571.28 Shares Owned After: 114,784 | Ownership: D (Direct) Footnotes: [F4] 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. [Transaction #5] Security: Common Stock Date: 2026-08-26 | Code: M (Exercise of derivative) Shares: +9 | Price: $0.00 Shares Owned After: 114,793 | 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 #6] Security: Common Stock Date: 2026-08-26 | Code: F (Payment of exercise/tax) Shares: -1,631 | Price: $468.88 Total Value: $764,743.28 Shares Owned After: 113,162 | 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 #7] Security: Common Stock Date: 2026-08-27 | Code: S (Open market sale) Shares: -1,007 | Price: $478.36 Total Value: $481,708.52 Shares Owned After: 112,155 | Ownership: D (Direct) Footnotes: [F4] 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: 2026-08-25 | Code: M (Exercise of derivative) Shares: -7.7788 | Price: $0.00 Shares Owned After: 287.0089 | 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. [Transaction #2] Security: Dividend Equivalent Rights Date: 2026-08-26 | Code: M (Exercise of derivative) Shares: -9.4687 | Price: $0.00 Shares Owned After: 277.5402 | 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: Represents the grant of restricted stock units to the Reporting Person. Each restricted stock unit represents a contingent right to receive one share of the Issuer's common stock. F4: 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 (2026-08-27)