Commodore holds 9.9% Alto Neuroscience (ANRO) via stock and warrants

Rhea-AI Filing Summary

Commodore Capital and related filers report a significant passive stake in Alto Neuroscience, Inc. They filed an amended Schedule 13G/A showing beneficial ownership of 3,245,628 shares of common stock, representing 9.9% of the class as of December 31, 2025.

The position consists of 1,823,196 Alto Neuroscience shares and 1,422,432 additional shares that each filer may acquire through exercising a pre-funded warrant, which is subject to a 9.99% beneficial ownership limitation. The calculation uses 31,066,335 shares outstanding as of November 7, 2025 plus the warrant shares. The filers certify the securities are not held to change or influence control of Alto Neuroscience.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

Alto Neuroscience, Inc.

(Name of Issuer)

Common Stock, $0.0001 par value per share

(Title of Class of Securities)

02157Q109

(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. 02157Q109

1

Names of Reporting Persons

Commodore Capital LP

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 3,245,628.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 3,245,628.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,245,628.00

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)

9.9 %

12

Type of Reporting Person (See Instructions)

IA, PN

SCHEDULE 13G

CUSIP No. 02157Q109

1

Names of Reporting Persons

Commodore Capital Master LP

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

CAYMAN ISLANDS

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 3,245,628.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 3,245,628.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,245,628.00

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)

9.9 %

12

Type of Reporting Person (See Instructions)

PN

SCHEDULE 13G

CUSIP No. 02157Q109

1

Names of Reporting Persons

Robert Egen Atkinson

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

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 3,245,628.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 3,245,628.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,245,628.00

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)

9.9 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

CUSIP No. 02157Q109

1

Names of Reporting Persons

Michael Kramarz

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

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 3,245,628.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 3,245,628.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,245,628.00

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)

9.9 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Alto Neuroscience, Inc.
(b)	Address of issuer's principal executive offices: 650 Castro Street, Suite 450, Mountain View, CALIFORNIA, 94041.
Item 2.
(a)	Name of person filing: Commodore Capital LP Commodore Capital Master LP Robert Egen Atkinson Michael Kramarz Each a "Filer."
(b)	Address or principal business office or, if none, residence: The address for Commodore Capital LP, Robert Egen Atkinson, and Michael Kramarz is 444 Madison Avenue, Floor 35, New York, NY 10022. The address for Commodore Capital Master LP is c/o Maples Corporate Services Limited, Ugland House, South Church Street, PO Box 309, Grand Cayman KY1-1104, Cayman Islands.
(c)	Citizenship: See Item 4 of the cover page for each Filer.
(d)	Title of class of securities: Common Stock, $0.0001 par value per share
(e)	CUSIP No.: 02157Q109
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: See Item 9 of the cover page for each Filer. This report on Schedule 13G is being filed by Commodore Capital LP (the "Firm"), Commodore Capital Master LP ("Commodore Master"), Michael Kramarz, and Robert Egen Atkinson. The Firm is the investment manager to Commodore Master. As of December 31, 2025, the Firm may be deemed to beneficially own an aggregate of 3,245,628 shares Common Stock, $0.0001 par value per share (the "Common Stock"), consisting of (i) 1,823,196 shares of the Common Stock and (ii) 1,422,432 shares of Common Stock each Filer has the right to acquire through the exercise of a pre-funded warrant ("Pre-Funded Warrant") of Alto Neuroscience, Inc. (the "Issuer"), which is subject to a beneficial ownership limitation of 9.99% (the "Beneficial Ownership Limitation"). The foregoing excludes 113,922 shares of Common Stock underlying the Pre-Funded Warrant, which is subject to the Beneficial Ownership Limitation. The Firm, as the investment manager to Commodore Master, may be deemed to beneficially own these securities. Michael Kramarz and Robert Egen Atkinson are the managing partners of the Firm and exercise investment discretion with respect to these securities. Ownership percentages are based on 31,066,335 Common Stock reported as issued and outstanding as of November 7, 2025 in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on November 12, 2025, plus 1,422,432 shares of Common Stock which the Filers may acquire upon the exercise of the Pre-Funded Warrant, subject to the Beneficial Ownership Limitation.
(b)	Percent of class: See Item 11 of the cover page for each Filer.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: See Item 5 of the cover page for each Filer.
	(ii) Shared power to vote or to direct the vote: See Item 6 of the cover page for each Filer.
	(iii) Sole power to dispose or to direct the disposition of: See Item 7 of the cover page for each Filer.
	(iv) Shared power to dispose or to direct the disposition of: See Item 8 of the cover page for each Filer.
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
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.
	Not Applicable
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.

Commodore Capital LP

Signature:	Michael Kramarz
Name/Title:	Managing Partner
Date:	02/17/2026

Commodore Capital Master LP

Signature:	Michael Kramarz
Name/Title:	Authorized Signatory
Date:	02/17/2026

Robert Egen Atkinson

Signature:	Robert Egen Atkinson
Name/Title:	Authorized Signatory
Date:	02/17/2026

Michael Kramarz

Signature:	Michael Kramarz
Name/Title:	Authorized Signatory
Date:	02/17/2026

Exhibit Information

Exhibit 1: Joint Filing Agreement

FAQ

What stake in Alto Neuroscience (ANRO) does Commodore Capital report?

Commodore Capital and related filers report beneficial ownership of 3,245,628 Alto Neuroscience common shares, equal to 9.9% of the outstanding class. This total includes both currently held shares and shares obtainable through a pre-funded warrant, based on the stated share count.

How is Commodore Capital’s 3,245,628-share Alto Neuroscience (ANRO) position structured?

The reported 3,245,628-share position in Alto Neuroscience consists of 1,823,196 common shares plus 1,422,432 shares that may be acquired via exercising a pre-funded warrant. This split highlights both existing ownership and additional shares accessible through the warrant structure.

What ownership limitation applies to Commodore’s Alto Neuroscience (ANRO) pre-funded warrant?

The pre-funded warrant held by the filers is subject to a 9.99% Beneficial Ownership Limitation. This cap restricts how many shares can be acquired through exercise, and 113,922 underlying shares are excluded from the reported beneficial ownership due to this limitation.

How was the 9.9% ownership in Alto Neuroscience (ANRO) calculated?

The filers state that the 9.9% figure is based on 31,066,335 Alto Neuroscience shares outstanding as of November 7, 2025, plus 1,422,432 shares issuable upon exercise of the pre-funded warrant. This combined number forms the denominator used for their percentage ownership.

Do Commodore Capital and affiliates seek to control Alto Neuroscience (ANRO)?

The filers certify that the Alto Neuroscience securities were not acquired and are not held for the purpose of changing or influencing control of the company. They also state the holdings are not part of any control-related transaction, other than potential proxy nomination activities referenced in the certification.

Who are the reporting persons in the Alto Neuroscience (ANRO) Schedule 13G/A?

The filing identifies Commodore Capital LP, Commodore Capital Master LP, Robert Egen Atkinson, and Michael Kramarz as reporting persons. Commodore Capital LP is the investment manager to Commodore Capital Master LP, and Atkinson and Kramarz are managing partners exercising investment discretion.