Jane Street reports 2.8% stake in ALT5 Sigma

Jane Street Group, LLC and related entities filed an amended Schedule 13G reporting beneficial ownership of 3,051,697 shares of ALT5 Sigma Corp common stock, representing 2.8% of the class as of the reporting date.

Accepted by SEC EDGAR 02/02/2026 - 04:14 PM EST Learn about SEC filing dates

Rhea-AI Filing Summary

Jane Street Group, LLC and related entities filed an amended Schedule 13G reporting beneficial ownership of 3,051,697 shares of ALT5 Sigma Corp common stock, representing 2.8% of the class as of the reporting date.

All shares are reported with shared voting and dispositive power and no sole power. The filing states the securities were not acquired or held to change or influence control of ALT5 Sigma Corp, indicating a passive investment position under the Schedule 13G framework.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How many ALT5 Sigma Corp (ALTS) shares does Jane Street report owning?

Jane Street Group, LLC reports beneficial ownership of 3,051,697 shares of ALT5 Sigma Corp common stock. This total reflects shares over which Jane Street entities have shared voting and shared dispositive power, as disclosed in the amended Schedule 13G filing.

What percentage of ALT5 Sigma Corp (ALTS) does Jane Street’s 13G/A represent?

Jane Street reports holding 2.8% of ALT5 Sigma Corp’s common stock. This percentage is based on 3,051,697 beneficially owned shares and indicates that Jane Street’s position is below the 5% threshold often associated with larger ownership stakes.

Which Jane Street entities are listed as reporting persons for ALT5 Sigma (ALTS)?

The filing lists four reporting persons: Jane Street Group, LLC, Jane Street Capital, LLC, Jane Street Options, LLC, and Jane Street Global Trading, LLC. Each entity is organized in Delaware and reports shared voting and dispositive power over specified ALT5 Sigma shares.

Does Jane Street seek to influence control of ALT5 Sigma Corp (ALTS)?

The certification states the securities were not acquired or held for changing or influencing control of ALT5 Sigma Corp. The position is characterized as passive under Schedule 13G, rather than part of any control or activist transaction regarding the issuer.

How are voting and dispositive powers over ALT5 Sigma (ALTS) shares allocated to Jane Street?

Jane Street reports 0 shares with sole voting or dispositive power and 3,051,697 shares with shared voting and shared dispositive power. This means decisions over these shares are made jointly among the reporting entities rather than by any single one alone.

Which Jane Street subsidiaries are identified as holding ALT5 Sigma (ALTS) securities?

The ownership section identifies Jane Street Capital, LLC, Jane Street Global Trading, LLC, and Jane Street Options, LLC as subsidiaries involved. Each subsidiary reports its own aggregate beneficial holdings as part of the overall 3,051,697 ALT5 Sigma shares.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 2)

ALT5 Sigma Corp

(Name of Issuer)

Common Stock, $0.001 par value per share

(Title of Class of Securities)

47089W104

(CUSIP Number)

12/31/2025

(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. 47089W104

1

Names of Reporting Persons

JANE STREET GROUP, LLC

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 3,051,697.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 3,051,697.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,051,697.00

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)

2.8 %

12

Type of Reporting Person (See Instructions)

HC

SCHEDULE 13G

CUSIP No. 47089W104

1

Names of Reporting Persons

Jane Street Capital, LLC

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 880,187.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 880,187.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

880,187.00

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)

0.8 %

12

Type of Reporting Person (See Instructions)

BD

SCHEDULE 13G

CUSIP No. 47089W104

1

Names of Reporting Persons

Jane Street Options, LLC

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 710,296.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 710,296.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

710,296.00

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)

0.7 %

12

Type of Reporting Person (See Instructions)

BD

SCHEDULE 13G

CUSIP No. 47089W104

1

Names of Reporting Persons

Jane Street Global Trading, LLC

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 1,461,214.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,461,214.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,461,214.00

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)

1.3 %

12

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13G

Item 1.
(a)	Name of issuer: ALT5 Sigma Corp
(b)	Address of issuer's principal executive offices: 325 E. WARM SPRINGS ROAD, 325 E. WARM SPRINGS ROAD, LAS VEGAS, NEVADA, 89119.
Item 2.
(a)	Name of person filing: Jane Street Group, LLC; Jane Street Capital, LLC; Jane Street Options, LLC; Jane Street Global Trading, LLC
(b)	Address or principal business office or, if none, residence: Jane Street Group, LLC 250 Vesey Street 6th Floor New York, NY 10281 Jane Street Capital, LLC 250 Vesey Street 6th Floor New York, NY 10281 Jane Street Options, LLC 250 Vesey Street 6th Floor New York, NY 10281 Jane Street Global Trading, LLC 250 Vesey Street 6th Floor New York, NY 10281
(c)	Citizenship: See Item 4 of Cover Page
(d)	Title of class of securities: Common Stock, $0.001 par value per share
(e)	CUSIP No.: 47089W104
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 3,051,697.00
(b)	Percent of class: 2.8 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0
	(ii) Shared power to vote or to direct the vote: 3,051,697.00
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 3,051,697.00
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	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. Subsidiary Jane Street Capital, LLC Jane Street Global Trading, LLC Jane Street Options, LLC
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

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.

JANE STREET GROUP, LLC

Signature:	/s/ Jeremy Kahn
Name/Title:	Jeremy Kahn (Authorized Signatory)
Date:	02/02/2026

Jane Street Capital, LLC

Signature:	/s/ Jeremy Kahn
Name/Title:	Jeremy Kahn (Authorized Signatory)
Date:	02/02/2026

Jane Street Options, LLC

Signature:	/s/ Jeremy Kahn
Name/Title:	Jeremy Kahn (Authorized Signatory)
Date:	02/02/2026

Jane Street Global Trading, LLC

Signature:	/s/ Jeremy Kahn
Name/Title:	Jeremy Kahn (Authorized Signatory)
Date:	02/02/2026