X0508 4 2025-11-05 0 0000106040 WESTERN DIGITAL CORP WDC 0001302874 Cole Martin I C/O WESTERN DIGITAL CORPORATION 5601 GREAT OAKS PARKWAY SAN JOSE CA 95119 1 0 0 0 1 Common Stock 2025-11-05 4 S 0 144 152.99 D 49360 D Common Stock 2025-11-05 4 S 0 221 155.7686 D 49139 D Common Stock 2025-11-05 4 S 0 419 157.0068 D 48720 D Common Stock 2025-11-05 4 S 0 833 158.0222 D 47887 D Common Stock 2025-11-05 4 S 0 551 159.1577 D 47336 D Common Stock 2025-11-05 4 S 0 982 160.2441 D 46354 D Common Stock 2025-11-05 4 S 0 960 161.3131 D 45394 D Common Stock 2025-11-05 4 S 0 3303 162.1765 D 42091 D Common Stock 2025-11-05 4 S 0 1231 163.0804 D 40860 D Common Stock 2025-11-05 4 S 0 798 164.081 D 40062 D Common Stock 2025-11-05 4 S 0 558 164.9907 D 39504 D The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the Reporting Person on August 1, 2025. Includes 1,701 additional stock units acquired by the Reporting Person in connection with the Issuer's spin-off (the "Spin-Off") of a then-wholly owned subsidiary of the Issuer on February 21, 2025. Pursuant to an Employee Matters Agreement, at the effective time of the Spin-Off, each outstanding Issuer stock unit was adjusted and converted into additional stock units based on the equity conversion ratio of 1.452526 per every Issuer stock unit. Represents the weighted average sale price per share. These shares were sold in multiple transactions at prices ranging from a low of $155.5927 to a high of $156.51. 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. Represents the weighted average sale price per share. These shares were sold in multiple transactions at prices ranging from a low of $156.59 to a high of $157.58. 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. Represents the weighted average sale price per share. These shares were sold in multiple transactions at prices ranging from a low of $157.59 to a high of $158.55. 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. Represents the weighted average sale price per share. These shares were sold in multiple transactions at prices ranging from a low of $158.60 to a high of $159.54. 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. Represents the weighted average sale price per share. These shares were sold in multiple transactions at prices ranging from a low of $159.69 to a high of $160.6804. 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. Represents the weighted average sale price per share. These shares were sold in multiple transactions at prices ranging from a low of $160.70 to a high of $161.69. 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. Represents the weighted average sale price per share. These shares were sold in multiple transactions at prices ranging from a low of $161.70 to a high of $162.69. 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. Represents the weighted average sale price per share. These shares were sold in multiple transactions at prices ranging from a low of $162.70 to a high of $163.68. 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. Represents the weighted average sale price per share. These shares were sold in multiple transactions at prices ranging from a low of $163.70 to a high of $164.68. 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. Represents the weighted average sale price per share. These shares were sold in multiple transactions at prices ranging from a low of $164.71 to a high of $165.35. 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. By: /s/ Sandra Garcia Attorney-in-Fact For: Martin I. Cole 2025-11-06