Western Digital Officer Files Form 144 to Sell $306K in Common Stock

Executive Summary

On October 21, 2026, Western Digital Corp ($WDC) officer Cynthia Lock Tregillis filed Form 144 indicating an intent to sell 807 shares of common stock with an estimated aggregate market value of $306,660.00. The shares were acquired on October 20, 2026, via restricted stock vesting.

Key Transaction Details

• Seller: Cynthia Lock Tregillis (Officer)
• Shares Proposed for Sale: 807 common shares
• Estimated Total Value: $306,660.00 (~$380.00 per share)
• Broker: Morgan Stanley Smith Barney LLC Executive Financial Services
• Trading Plan: Executed under a Rule 10b5-1 trading plan adopted on March 6, 2026

Context and Recent Sales Activity

The filing lists multiple prior sales in the past three months under the same trading plan:

• 09/04/2026: 432 shares for $194,918.40
• 08/27/2026: 1,007 shares for $481,708.52
• 08/26/2026: 476 shares for $214,571.28
• 08/24/2026: 684 shares for $305,180.28
• 08/21/2026: 235 shares for $112,158.45

Significance

The trading significance is rated Low. The transaction represents a small volume relative to Western Digital's 360,540,944 outstanding shares, is driven by restricted stock vesting, and is executed pursuant to a pre-scheduled Rule 10b5-1 trading plan.