EcoR1 Capital discloses 5.8% Alto Neuroscience (ANRO) stake in Schedule 13G

Rhea-AI Filing Summary

Alto Neuroscience, Inc. has a significant shareholder group led by EcoR1 Capital. EcoR1 Capital, LLC and its control person, Oleg Nodelman, each report beneficial ownership of 2,232,000 shares of Alto Neuroscience common stock, representing 5.8% of the class. EcoR1 Capital Fund Qualified, L.P. reports beneficial ownership of 2,065,935 shares, or 5.3% of the common stock. These percentages are calculated using 38,829,167 shares outstanding following the closing of an offering described in a July 14, 2026 prospectus. The reporting persons have no sole voting or dispositive power over the shares but share voting and dispositive power in the amounts reported. They state that the securities were acquired and are held without the purpose or effect of changing or influencing control of Alto Neuroscience.

Key Figures

EcoR1/Nodelman beneficial ownership: 2,232,000 shares EcoR1/Nodelman ownership percentage: 5.8% Qualified Fund beneficial ownership: 2,065,935 shares +3 more

6 metrics

EcoR1/Nodelman beneficial ownership 2,232,000 shares Common Stock beneficially owned by EcoR1 Capital, LLC and Oleg Nodelman

EcoR1/Nodelman ownership percentage 5.8% Percentage of Alto Neuroscience common stock class owned by EcoR1 Capital, LLC and Oleg Nodelman

Qualified Fund beneficial ownership 2,065,935 shares Common Stock beneficially owned by EcoR1 Capital Fund Qualified, L.P.

Qualified Fund ownership percentage 5.3% Percentage of Alto Neuroscience common stock class owned by EcoR1 Capital Fund Qualified, L.P.

Shares outstanding baseline 38,829,167 shares Common Stock outstanding after closing of offering in prospectus filed July 14, 2026

Shared voting power EcoR1/Nodelman 2,232,000 shares Shares of Alto Neuroscience common stock over which EcoR1 and Nodelman share voting power

Key Terms

beneficial owner, pecuniary interest, shared voting power, Schedule 13G, +1 more

5 terms

beneficial owner regulatory

"it disclaims that it is, a beneficial owner, as defined in Rule 13d-3"

A beneficial owner is the person who ultimately owns or controls a financial asset or property, even if their name isn't directly on official documents. Think of it like someone who secretly holds the keys to a safe deposit box—others may appear to have access, but the true owner is the one who benefits from what's inside. Identifying beneficial owners helps ensure transparency and prevent illegal activities like money laundering or fraud.

pecuniary interest financial

"disclaims beneficial ownership of the securities reported herein except to the extent of that person's pecuniary interest"

shared voting power financial

"Shared Voting Power 2,232,000.00"

Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.

Schedule 13G regulatory

"EXHIBIT 99 - AGREEMENT REGARDING JOINT FILING OF STATEMENT ON SCHEDULE 13D OR 13G"

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

dispositive power financial

"Shared Dispositive Power 2,232,000.00"

Dispositive power is the authority to decide the final outcome of an asset, legal claim, contract, or corporate action — in effect the power to dispose of or resolve something. For investors it matters because whoever holds that authority can determine who gets paid, who controls an asset or vote, and how risks and returns are allocated; think of it like holding the key that lets you lock in the winner or loser in a deal.

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

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Available on EDGAR 07/20/2026 - 05:11 PM Accepted by SEC EDGAR 07/20/2026 - 05:10 PM Learn about SEC filing dates

FAQ

What percentage of Alto Neuroscience (ANRO) does EcoR1 Capital beneficially own?

EcoR1 Capital, LLC and Oleg Nodelman each report 5.8% beneficial ownership of Alto Neuroscience common stock, based on 2,232,000 shares out of 38,829,167 shares outstanding after a recent offering.

How many Alto Neuroscience (ANRO) shares does EcoR1 Capital Fund Qualified, L.P. hold?

EcoR1 Capital Fund Qualified, L.P. reports beneficial ownership of 2,065,935 shares of Alto Neuroscience common stock, representing 5.3% of the outstanding shares calculated on 38,829,167 shares outstanding.

Does EcoR1 Capital have control intent over Alto Neuroscience (ANRO)?

The reporting persons certify the securities were not acquired and are not held for changing or influencing control of Alto Neuroscience and are not held in connection with any transaction having that purpose or effect, other than nomination-related activities described under Item 11.

What voting power does EcoR1 Capital report for its Alto Neuroscience (ANRO) stake?

EcoR1 Capital, LLC and Oleg Nodelman each report 0 sole voting power and 2,232,000 shares of shared voting power. EcoR1 Capital Fund Qualified, L.P. reports 2,065,935 shares of shared voting power and no sole voting power.

On what share count is the EcoR1 ownership percentage in Alto Neuroscience (ANRO) based?

The reported ownership percentages are calculated using 38,829,167 shares of Alto Neuroscience common stock outstanding, measured after the closing of an offering described in a prospectus filed on July 14, 2026.

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

The reporting persons are EcoR1 Capital, LLC, EcoR1 Capital Fund Qualified, L.P., and Oleg Nodelman. EcoR1 is general partner and investment adviser to funds including Qualified Fund, and Mr. Nodelman is the control person of EcoR1.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Alto Neuroscience, Inc.

(Name of Issuer)

Comon Stock

(Title of Class of Securities)

02157Q109

(CUSIP Number)

07/13/2026

(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)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 02157Q109

1

Names of Reporting Persons

EcoR1 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 2,232,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,232,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,232,000.00

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)

5.8 %

12

Type of Reporting Person (See Instructions)

IA, OO

Comment for Type of Reporting Person: Percentage calculated based on 38,829,167 shares of Common Stock outstanding following the closing of the offering of the Issuer's Common Stock reported in the Prospectus filed by the Issuer on July 14, 2026.

SCHEDULE 13G

CUSIP Number(s): 02157Q109

1

Names of Reporting Persons

Oleg Nodelman

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 2,232,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,232,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,232,000.00

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)

5.8 %

12

Type of Reporting Person (See Instructions)

HC, IN

Comment for Type of Reporting Person: Percentage calculated based on 38,829,167 shares of Common Stock outstanding following the closing of the offering of the Issuer's Common Stock reported in the Prospectus filed by the Issuer on July 14, 2026.

SCHEDULE 13G

CUSIP Number(s): 02157Q109

1

Names of Reporting Persons

EcoR1 Capital Fund Qualified, L.P.

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 2,065,935.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,065,935.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,065,935.00

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)

5.3 %

12

Type of Reporting Person (See Instructions)

PN

Comment for Type of Reporting Person: Percentage calculated based on 38,829,167 shares of Common Stock outstanding following the closing of the offering of the Issuer's Common Stock reported in the Prospectus filed by the Issuer on July 14, 2026.

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, CA 94041
Item 2.
(a)	Name of person filing: EcoR1 Capital, LLC, a Delaware limited liability company ("EcoR1") EcoR1 Capital Fund Qualified, L.P., a Delaware limited partnership ("Qualified Fund") Oleg Nodelman Qualified Fund is filing this statement jointly with the other reporting persons, but not as a member of a group, and it expressly disclaims membership in a group. In addition, the filing of this Schedule 13G on behalf of Qualified Fund should not be construed as an admission that it is, and it disclaims that it is, a beneficial owner, as defined in Rule 13d-3 under the Act, of any securities covered by this Schedule 13G. Each reporting person also disclaims beneficial ownership of the securities reported herein except to the extent of that person's pecuniary interest therein.
(b)	Address or principal business office or, if none, residence: 357 Tehama Street #3 San Francisco, CA 94103
(c)	Citizenship: See Item 4 of the cover sheet for each reporting person.
(d)	Title of class of securities: Comon Stock
(e)	CUSIP Number(s): 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: EcoR1: 2,232,000 Oleg Nodelman: 2,232,000 Qualified Fund: 2,065,935
(b)	Percent of class: EcoR1: 5.8% Oleg Nodelman: 5.8% Qualified Fund: 5.3%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: EcoR1: 0 Oleg Nodelman: 0 Qualified Fund: 0
	(ii) Shared power to vote or to direct the vote: EcoR1: 2,232,000 Oleg Nodelman: 2,232,000 Qualified Fund: 2,065,935
	(iii) Sole power to dispose or to direct the disposition of: EcoR1: 0 Oleg Nodelman: 0 Qualified Fund: 0
	(iv) Shared power to dispose or to direct the disposition of: EcoR1: 2,232,000 Oleg Nodelman: 2,232,000 Qualified Fund: 2,065,935
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.
	If a group has filed this schedule pursuant to §240.13d-1(b)(1)(ii)(K), so indicate under Item 3(k) 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. EcoR1 is the general partner and investment adviser of investment funds, including Qualified Fund. Mr. Nodelman is the control person of EcoR1.
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 acquired and are held in the ordinary course of business and 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. 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.

EcoR1 Capital, LLC

Signature:	/s/ Oleg Nodelman
Name/Title:	Manager
Date:	07/20/2026

Oleg Nodelman

Signature:	/s/ Oleg Nodelman
Name/Title:	Reporting person
Date:	07/20/2026

EcoR1 Capital Fund Qualified, L.P.

Signature:	/s/ Oleg Nodelman
Name/Title:	Manager of the General Partner, EcoR1 Capital, LLC
Date:	07/20/2026

Exhibit Information

EXHIBIT 99 - AGREEMENT REGARDING JOINT FILING OF STATEMENT ON SCHEDULE 13D OR 13G