TREGILLIS CYNTHIA L (Chief Legal Officer & Corp Sec) sold 1.3% of their position (1.48K shares) of WESTERN DIGITAL CORP on the open market

Open‑market sale worth $696.3K — a minor trim. Review remaining holdings and any 10b5‑1 plan disclosures.

S · 2 sales

TREGILLIS CYNTHIA L

Filed: 8/28/2026ACC: 0001266824-26-000188

InsiderTREGILLIS CYNTHIA LCIK 2057088

→

IssuerWESTERN DIGITAL CORPCIK 106040

Officer· Chief Legal Officer & Corp Sec

Since Mar 2026

-8.25

Net shares

Net seller

$1.81M

Total sold

Open market trades

0B · 2S

Total transactions

3.89K acquired · 3.90K disposed

Non-Derivative Transactions7

Common Stock

Direct

M · Option Exercise

+7.00

Price / share

—

Trade value

—

% of position

0.0%

8/25/2026

112.15K→112.15K

Common Stock

Direct

F · Tax Withholding

−771.00

Price / share

$450.75

Trade value

$347.53K

% of position

0.7%

8/25/2026

112.15K→111.38K

Common Stock

Direct

A · Award

+3.88K

Price / share

—

Trade value

—

% of position

3.5%

8/25/2026

111.38K→115.26K

Common Stock

Direct

S · Sale

−476.00

Price / share

$450.78

Trade value

$214.57K

% of position

0.4%

8/26/2026

115.26K→114.78K

Common Stock

Direct

M · Option Exercise

+9.00

Price / share

—

Trade value

—

% of position

0.0%

8/26/2026

114.78K→114.79K

Common Stock

Direct

F · Tax Withholding

−1.63K

Price / share

$468.88

Trade value

$764.74K

% of position

1.4%

8/26/2026

114.79K→113.16K

Common Stock

Direct

S · Sale

−1.01K

Price / share

$478.36

Trade value

$481.71K

% of position

0.9%

8/27/2026

113.16K→112.16K

Total

Net shares

+9.00

Net value

-$1.81M

Security	Date	Type	Shares	Price / Share	Trade Value	% of Position	Held Before	Held After
Common Stock Direct	8/25/2026	M · Option Exercise	+7.00	—	—	0.0%	112.15K	112.15K
Common Stock Direct	8/25/2026	F · Tax Withholding	−771.00	$450.75	$347.53K	0.7%	112.15K	111.38K
Common Stock Direct	8/25/2026	A · Award	+3.88K	—	—	3.5%	111.38K	115.26K
Common Stock Direct	8/26/2026	S · Sale	−476.00	$450.78	$214.57K	0.4%	115.26K	114.78K
Common Stock Direct	8/26/2026	M · Option Exercise	+9.00	—	—	0.0%	114.78K	114.79K
Common Stock Direct	8/26/2026	F · Tax Withholding	−1.63K	$468.88	$764.74K	1.4%	114.79K	113.16K
Common Stock Direct	8/27/2026	S · Sale	−1.01K	$478.36	$481.71K	0.9%	113.16K	112.16K
Total			+9.00		-$1.81M

Derivative Transactions2

Dividend Equivalent Rights

Direct

M · Option Exercise

Converts to

Common Stock

7.78 shares

−7.78

Strike price

Held after

287.01

Exercisable

—

8/25/2026

Dividend Equivalent Rights

Direct

M · Option Exercise

Converts to

Common Stock

9.47 shares

−9.47

Strike price

Held after

277.54

Exercisable

—

8/26/2026

Security	Converts To	Date	Type	Shares	Strike Price	Exercisable	Held After
Dividend Equivalent Rights Direct	Common Stock7.78 shares	8/25/2026	M · Option Exercise	−7.78		—	287.01
Dividend Equivalent Rights Direct	Common Stock9.47 shares	8/26/2026	M · Option Exercise	−9.47		—	277.54