Alto Neuroscience, Inc. Schedule 13G reports that Sirenia Capital Management and Alex Silverstein together beneficially hold 2,591,587 shares of Common Stock, representing 7.9% of the class assuming exercise of certain warrants.
Securities outstanding were 31,945,516 shares as of March 16, 2026, per the referenced proxy statement. The position includes 787,043 shares issuable upon exercise of warrants, and the filing is made under Rule 13d-1(k) as a joint filing.
Positive
None.
Negative
None.
Insights
Holds a meaningful passive stake disclosed via Schedule 13G.
The filing states a combined position of 2,591,587 shares representing 7.9% of common stock on a fully exercised basis. The percentage is calculated using 31,945,516 shares outstanding as of March 16, 2026.
Ownership includes 787,043 warrants exercisable into common stock. Future activity depends on whether warrants are exercised and any change in outstanding shares; timing and cash-flow treatment are not specified in the provided excerpt.
Key Figures
Shares beneficially owned:2,591,587 sharesPercent of class:7.9%Shares outstanding:31,945,516 shares+1 more
4 metrics
Shares beneficially owned2,591,587 sharesreported combined holding by Sirenia and Alex Silverstein
Percent of class7.9%calculated assuming exercise of warrants
Shares outstanding31,945,516 sharesas of <date>March 16, 2026</date>
Warrants issuable787,043 sharesincluded in the reported position as issuable upon exercise
Key Terms
Schedule 13G, warrants, shared dispositive power
3 terms
Schedule 13Gregulatory
"This statement is filed by: (i) Sirenia Capital Management LP"
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.
warrantsfinancial
"Includes 787,043 shares of Common Stock issuable upon exercise of warrants"
Warrants are special documents that give you the right to buy a company's stock at a set price before a certain date. They are often used as a way for companies to attract investors or raise money, and their value can increase if the company's stock price goes up.
What stake does Sirenia Capital report in Alto Neuroscience (ANRO)?
They report beneficial ownership of 2,591,587 shares, representing 7.9% of the class on a fully exercised basis. The percentage uses an outstanding share count of 31,945,516 as of March 16, 2026 from the issuer's proxy statement.
Does the reported position include warrants or other exercisable securities?
Yes. The filing states the position includes 787,043 shares of Common Stock issuable upon exercise of warrants held by the Sirenia Fund. That warrant-derived amount is included in the reported 2,591,587 shares figure and percentage.
Who filed the Schedule 13G for ANRO and under what authority?
The statement is jointly filed by Sirenia Capital Management LP and Alex Silverstein pursuant to Rule 13d-1(k). A Joint Filing Agreement (Exhibit 99.1) is referenced and incorporated into the filing.
What outstanding share count was used to calculate the 7.9% stake?
The filing uses an aggregate outstanding share count of 31,945,516 shares as of March 16, 2026, cited from the issuer's Definitive Proxy Statement on Schedule 14A filed March 26, 2026, to calculate the 7.9% figure.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
Alto Neuroscience, Inc.
(Name of Issuer)
Common Stock, par value $0.0001 per share
(Title of Class of Securities)
02157Q109
(CUSIP Number)
03/31/2026
(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
Sirenia Capital Management 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
2,591,587.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
2,591,587.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
2,591,587.00
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)
7.9 %
12
Type of Reporting Person (See Instructions)
IA, PN
Comment for Type of Reporting Person: Includes 787,043 shares of Common Stock (as defined in Item 2(a)) issuable upon exercise of warrants.
SCHEDULE 13G
CUSIP Number(s):
02157Q109
1
Names of Reporting Persons
Alex Silverstein
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
2,591,587.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
2,591,587.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
2,591,587.00
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)
7.9 %
12
Type of Reporting Person (See Instructions)
HC, IN
Comment for Type of Reporting Person: Includes 787,043 shares of Common Stock issuable upon exercise of warrants.
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
Alto Neuroscience, Inc.
(b)
Address of issuer's principal executive offices:
650 Castro St, Suite 450, Mountain View, CA 94041
Item 2.
(a)
Name of person filing:
This statement is filed by:
(i) Sirenia Capital Management LP ("Sirenia") with respect to the common stock, par value $0.0001 per share ("Common Stock"), of Alto Neuroscience, Inc. (the "Issuer") held by, and issuable upon exercise of warrants held by, SILV Fund, Ltd. (the "Sirenia Fund"), an investment fund it manages; and
(ii) Alex Silverstein ("Mr. Silverstein"), the managing member of Sirenia Capital Management GP LLC, the general partner of Sirenia, with respect to the Common Stock held by, and issuable upon exercise of warrants held by, the Sirenia Fund.
The foregoing persons are hereinafter sometimes collectively referred to as the "Reporting Persons."
The filing of this statement should not be construed as an admission that any of the foregoing persons or any Reporting Person is, for the purposes of Section 13 of the Securities Exchange Act of 1934, the beneficial owner of the securities reported herein.
Sirenia and Mr. Silverstein have entered into a Joint Filing Agreement, a copy of which is filed with this Schedule 13G as Exhibit 99.1, pursuant to which they have agreed to file this Schedule 13G jointly in accordance with the provisions of Rule 13d-1(k) of the Securities Exchange Act of 1934 (the "Act").
(b)
Address or principal business office or, if none, residence:
The address of the principal business office of Sirenia and Mr. Silverstein is 1674 Meridian Avenue, Suite 320, Miami Beach, FL 33139.
(c)
Citizenship:
Sirenia is a Delaware limited partnership. Mr. Silverstein is a United States citizen.
(d)
Title of class of securities:
Common Stock, par value $0.0001 per share
(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:
The information required by Item 4(a) is set forth in Row 9 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
The percentage set forth in this Schedule 13G is calculated based upon an aggregate of 31,945,516 shares of Common Stock outstanding as of March 16, 2026, as reported in the Issuer's Definitive Proxy Statement on Schedule 14A filed with the Securities and Exchange Commission on March 26, 2026, and assumes the exercise of the warrants held by the Sirenia Fund.
(b)
Percent of class:
7.9%
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
The information required by Item 4(c)(i) is set forth in Row 5 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(ii) Shared power to vote or to direct the vote:
The information required by Item 4(c)(ii) is set forth in Row 6 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(iii) Sole power to dispose or to direct the disposition of:
The information required by Item 4(c)(iii) is set forth in Row 7 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
(iv) Shared power to dispose or to direct the disposition of:
The information required by Item 4(c)(iv) is set forth in Row 8 of the cover page for each of the Reporting Persons and is incorporated herein by reference.
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.
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.
See Item 2(a). The Sirenia Fund has the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, more than 5 percent of the outstanding Common Stock.
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 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.
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.
Sirenia Capital Management LP
Signature:
/s/ Kolby Loft
Name/Title:
Kolby Loft, General Counsel & Chief Compliance Officer
