[SCHEDULE 13G/A] Sandisk Corporation SEC Filing

Rhea-AI Filing Summary

Alpha Teknova, Inc. (TKNO) – Form 4 insider transaction

Director Martha J. Demski reported a single open-market sale of the company’s common stock on 27 June 2025. The transaction was executed under a Rule 10b5-1 trading plan adopted 12 March 2025 and was expressly intended to cover tax obligations arising from the vesting of director restricted stock units.

• Securities sold: 8,000 common shares
• Sale price: $5.064 per share
• Gross proceeds: approximately $40,512
• Post-transaction ownership: 12,000 common shares held directly

No derivative securities were acquired or disposed of, and no other transactions were reported. After the sale, Demski retains a direct equity interest in the company, but her share count declined by 40% from 20,000 to 12,000 shares. Because the disposition was pre-programmed under a 10b5-1 plan and earmarked for tax withholding, it is generally viewed as administrative rather than indicative of a changed outlook. Nevertheless, investors often monitor insider sales—especially by board members—for potential signaling effects. The filing does not disclose any changes to Demski’s role, company strategy, or financial performance.

Positive

• Transparent 10b5-1 plan: Sale executed under a pre-adopted trading plan, enhancing disclosure and reducing potential for opportunistic trades.

Negative

• 40% reduction in director holdings: Insider’s share count falls from 20,000 to 12,000, which may signal lower personal exposure to future upside.

Insights

Securities Analyst

TL;DR: Minor, pre-scheduled insider sale; neutral valuation impact.

The director sold 8,000 TKNO shares (40% of her stake) at $5.064 under a 10b5-1 plan to pay taxes on vested RSUs. Because the sale was predetermined and purpose-specific, it does not necessarily reflect her view of the company’s fundamentals. Remaining ownership of 12,000 shares shows continued alignment. Dollar value (~$40k) is immaterial relative to trading volume and market cap, so I view the filing as not impactful to valuation.

Corporate Governance Expert

TL;DR: Insider sale reduces alignment; slight governance negative.

Although executed under a compliant 10b5-1 plan, the 40% reduction in holdings lessens Demski’s direct exposure to TKNO’s equity performance. Frequent or sizeable director sales can raise questions about board-level confidence. Still, continued ownership and transparent disclosure mitigate concerns. Overall governance impact is mildly negative but limited.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

Sandisk Corporation

(Name of Issuer)

Common Stock, $0.01 Par Value Per Share

(Title of Class of Securities)

80004C200

(CUSIP Number)

06/30/2025

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

SCHEDULE 13G

CUSIP No. 80004C200

1

Names of Reporting Persons

Western Digital Corporation

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 7,513,019.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

7,513,019.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

5.2 %

12

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Sandisk Corporation
(b)	Address of issuer's principal executive offices: 951 Sandisk, Drive, Milpitas, CA 95035
Item 2.
(a)	Name of person filing: Western Digital Corporation
(b)	Address or principal business office or, if none, residence: 5601 Great Oaks Parkway, San Jose, CA 95119
(c)	Citizenship: Delaware
(d)	Title of class of securities: Common Stock, $0.01 Par Value Per Share
(e)	CUSIP No.: 80004C200
Item 4.	Ownership
(a)	Amount beneficially owned: 7,513,019 shares of common stock.
(b)	Percent of class: 5.2%. The percent of class is based on 145,299,942 shares of common stock outstanding as of May 19, 2025, as reported in the prospectus of Sandisk, filed on June 6, 2025 with the Securities and Exchange Commission pursuant to Rule 424(b)(4) of the Securities Act of 1933, as amended.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0. In connection with the separation of Sandisk Corporation from Western Digital Corporation, Western Digital Corporation and Sandisk Corporation entered into a Stockholder's and Registration Rights Agreement, dated as of February 21, 2025, pursuant to which Western Digital Corporation granted to Sandisk Corporation a proxy to vote the shares of Sandisk Corporation common stock owned by Western Digital Corporation in proportion to the votes cast by Sandisk Corporation's other stockholders. As a result, Western Digital Corporation does not exercise voting power over any of the shares of Sandisk Corporation common stock that it beneficially owns.
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 7,513,019
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. Not Applicable.
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. Not Applicable.
Item 8.	Identification and Classification of Members of the Group.
	If a group has filed this schedule pursuant to §240.13d-1(b)(1)(ii)(J), so indicate under Item 3(j) and attach an exhibit stating the identity and Item 3 classification of each member of the group. If a group has filed this schedule pursuant to §240.13d-1(c) or §240.13d-1(d), attach an exhibit stating the identity of each member of the group. Not Applicable.
Item 9.	Notice of Dissolution of Group.
	Notice of dissolution of a group may be furnished as an exhibit stating the date of the dissolution and that all further filings with respect to transactions in the security reported on will be filed, if required, by members of the group, in their individual capacity. See Item 5. Not Applicable.

Item 10.	Certifications:
	Not Applicable

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Western Digital Corporation

Signature:	/s/ Cynthia Tregillis
Name/Title:	Cynthia Tregillis, Executive Vice President, Chief Legal Officer and Secretary
Date:	07/01/2025

FAQ

Who sold Alpha Teknova (TKNO) shares in the latest Form 4?

Director Martha J. Demski reported the transaction.

How many TKNO shares were sold and at what price?

She sold 8,000 shares at $5.064 per share.

What is Martha Demski’s remaining ownership after the sale?

She now holds 12,000 common shares directly.

Why was the sale executed?

The sale was made to cover tax obligations related to vesting RSUs and was executed under a Rule 10b5-1 plan.

When was the 10b5-1 plan adopted?

The trading plan was adopted on 12 March 2025.

Were any derivative securities involved?

No derivative securities were acquired or disposed of in this filing.