Tregillis Cynthia L 4

What Happened
Cynthia L. Tregillis, Chief Legal Officer & Corporate Secretary of Western Digital (WDC), reported a mix of derivative conversions, tax-withholding and an open-market sale tied to vesting activity. On Jan 20, 2026 she converted small derivative/dividend-equivalent amounts (about 22.133 shares total) into common stock (reported at $0 exercise price). Also on Jan 20, 842 shares were withheld to cover tax obligations (value reported at $222.97 per share, $187,741). On Jan 21, 2026 she sold 447 shares in the open market at $229.00 per share for proceeds of $102,363. The open-market sale was effected under a Rule 10b5-1 trading plan.

Key Details

• Transaction dates and prices:
  • Jan 20, 2026: Conversion/exercise of derivative/dividend-equivalent shares — 11 and 11.133 shares reported (exercise price $0).
  • Jan 20, 2026: Tax withholding — 842 shares withheld at $222.97/share = $187,741 (F2).
  • Jan 21, 2026: Open-market sale — 447 shares at $229.00/share = $102,363 (F3).
• Notable footnotes:
  • F1: Dividend equivalent rights converted 1-for-1 into shares on RSU vesting; fractional amount settled in cash.
  • F2: 842-share disposition represents shares withheld to satisfy tax obligations upon vesting.
  • F3: The Jan 21 sale was executed under a Rule 10b5-1 trading plan adopted May 23, 2025.
• Shares owned after the transactions: not specified in the provided filing excerpt.
• Filing timeliness: Form filed Jan 21, 2026 for transactions on Jan 20–21, 2026 — no late filing indicated.

Context
This filing reflects routine vesting and tax-withholding activity plus a preplanned sale. The conversion entries reflect dividend-equivalent or derivative-to-stock conversions associated with RSU vesting; the large 842-share entry is a tax-withholding surrender, not a cash purchase or investment. The 447-share sale was conducted under a 10b5-1 plan, which typically means sales were pre-scheduled rather than ad hoc trading.