X0306 4 2021-08-26 0 0000106040 WESTERN DIGITAL CORP WDC 0001192521 EULAU ROBERT K 5601 GREAT OAKS PARKWAY SAN JOSE CA 95119 0 1 0 0 EVP & CFO Common Stock 2021-08-26 4 A 0 1685 0 A 131981 D Dividend Equivalent Rights 2021-08-26 4 A 0 46.8879 0 A Common Stock 46.8879 1202.6627 D Represents stock units that have been earned by the Reporting Person as payment in respect of the vesting of performance-based restricted stock units. These shares are scheduled to vest on September 4, 2022. The amount of securities beneficially owned by the Reporting Person, as disclosed in two Form 4s filed by the Reporting Person on August 31, 2021 and September 7, 2021 (together, the "Subsequent Form 4s"), did not give effect to the transaction reported herein. As a result, the Subsequent Form 4s underreported the number of share of the Issuer's common stock beneficially owned by the Reporting Person by 1,685 shares. As of the filing of this report and after giving effect to the transaction reported herein, the Reporting Person beneficially owns 131,981 shares of the Issuer's common stock. These shares represent the number of incremental dividend equivalents awarded based on the achievement rate of the related performance-based restricted stock units. The amount of securities beneficially owned by the Reporting Person, as disclosed in the Subsequent Form 4s, did not give effect to the transaction reported herein. As a result, the Subsequent Form 4s underreported the number of dividend equivalents beneficially owned by the Reporting Person by 46.8879. As of the filing of this report and after giving effect to the transaction reported herein, the Reporting Person beneficially owns 1,202.6627 dividend equivalents. /s/ Sandra Garcia Attorney-in-Fact for Robert K. Eulau 2021-09-17