Xilio Therapeutics disclosure: Sirenia Capital Management and Alex Silverstein report beneficial ownership of 1,142,862 shares of Common Stock, equal to 9.9% of the class based on March 18, 2026 outstanding shares. The reported total includes 857,148 shares issuable upon exercise of the Reported Warrants, which are subject to a 9.99% Blocker; as a result, the Reporting Persons cannot exercise the warrants to exceed the blocker.
The percentage calculation uses an aggregate of 5,782,511 shares outstanding as of March 18, 2026, per the issuer's Form 10-K. The filing is made jointly by Sirenia and Mr. Silverstein under a Joint Filing Agreement.
Positive
None.
Negative
None.
Insights
Large passive position reported with exercise limits.
The filing shows Sirenia Capital Management and Alex Silverstein hold or control 1,142,862 shares representing 9.9% of the outstanding Common Stock based on March 18, 2026. The position includes 857,148 warrants shown as exercisable but constrained by a 9.99% Blocker.
Governance implications depend on whether the position is passive under Rule 13d-1; the Joint Filing Agreement is filed as Exhibit 99.1. Subsequent filings would clarify intent if the holder moves beyond passive status.
Warrants are exercisable but subject to an ownership cap.
The disclosure states the percentage figures assume exercise of the Reported Warrants but also makes clear the Reporting Persons "cannot exercise" warrants to the extent doing so would exceed the 9.99% Blocker. The filing ties the percent of class to 5,782,511 shares outstanding as reported in the issuer's Form 10-K.
Legal risk centers on compliance with Rule 13d-1 filing requirements; this Schedule 13G indicates a joint filing and quantifies shared voting and dispositive power. Further legal interpretation would rely on additional context in future SEC filings.
Key Figures
Reported shares beneficially owned:1,142,862 sharesWarrants issuable shares:857,148 sharesPercent of class:9.9%+1 more
4 metrics
Reported shares beneficially owned1,142,862 sharesReported beneficial ownership by Sirenia/Mr. Silverstein
Warrants issuable shares857,148 sharesShares issuable upon exercise of the Reported Warrants
Percent of class9.9%Percent of class giving effect to 9.99% Blocker
Shares outstanding used5,782,511 sharesAggregate outstanding shares as of March 18, 2026 (Form 10-K)
What stake does Sirenia Capital report in Xilio Therapeutics (XLO)?
Sirenia Capital reports beneficial ownership of 1,142,862 shares, equal to 9.9% of outstanding Common Stock based on March 18, 2026 and the issuer's Form 10-K.
How many shares are issuable upon exercise of the reported warrants?
The filing states 857,148 shares are issuable upon exercise of the Reported Warrants; these are included in the reported 1,142,862-share figure in the Schedule 13G.
What is the 9.99% Blocker referenced in the filing?
The 9.99% Blocker prevents exercise of the Reported Warrants to the extent exercise would cause beneficial ownership to exceed 9.99% of outstanding Common Stock, limiting full exercise now.
On what outstanding share count is the percentage calculated?
The percentage is calculated using an aggregate of 5,782,511 shares outstanding as of March 18, 2026, per the issuer's Annual Report on Form 10-K filed March 23, 2026.
Who filed the Schedule 13G for Xilio and how was it filed?
The Schedule 13G was filed jointly by Sirenia Capital Management LP and Alex Silverstein under a Joint Filing Agreement, attached as Exhibit 99.1 to the statement.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
Xilio Therapeutics, Inc.
(Name of Issuer)
Common Stock, par value $0.0001 per share
(Title of Class of Securities)
98422T100
(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):
98422T100
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
1,142,862.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,142,862.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,142,862.00
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
Comment for Type of Reporting Person: Includes 857,148 shares of Common Stock (as defined in Item 2(a)) issuable upon exercise of the Reported Warrants (as defined in Item 4(a)). As more fully described in Item 4, the Reported Warrants are subject to the 9.99% Blocker (as defined in Item 4(a)) and the percentage set forth on row (11) gives effect to the 9.99% Blocker. However, rows (6), (8) and (9) show the number of shares of Common Stock that would be issuable upon the full exercise of the Reported Warrants and does not give effect to the 9.99% Blocker. Therefore, the actual number of shares of Common Stock beneficially owned by such Reporting Person, after giving effect to the 9.99% Blocker, is less than the number of securities reported on rows (6), (8) and (9).
SCHEDULE 13G
CUSIP Number(s):
98422T100
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
1,142,862.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,142,862.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,142,862.00
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
Comment for Type of Reporting Person: Includes 857,148 shares of Common Stock issuable upon exercise of the Reported Warrants. As more fully described in Item 4, the Reported Warrants are subject to the 9.99% Blocker and the percentage set forth on row (11) gives effect to the 9.99% Blocker. However, rows (6), (8) and (9) show the number of shares of Common Stock that would be issuable upon the full exercise of the Reported Warrants and does not give effect to the 9.99% Blocker. Therefore, the actual number of shares of Common Stock beneficially owned by such Reporting Person, after giving effect to the 9.99% Blocker, is less than the number of securities reported on rows (6), (8) and (9).
SCHEDULE 13G
Item 1.
(a)
Name of issuer:
Xilio Therapeutics, Inc.
(b)
Address of issuer's principal executive offices:
828 Winter Street, Suite 300, Waltham, MA 02451
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 Xilio Therapeutics, Inc. (the "Issuer") held by, and issuable upon exercise of the Reported Warrants held by a managed account it manages (the "Sirenia Account"); 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 Reported Warrants held by, the Sirenia Account.
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):
98422T100
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 5,782,511 shares of Common Stock outstanding as of March 18, 2026, as reported in the Issuer's Annual Report on Form 10-K for the fiscal year ended December 31, 2025, filed with the Securities and Exchange Commission on March 23, 2026, and assumes the exercise of the warrants (the "Reported Warrants") held by the Sirenia Account.
Pursuant to the terms of the Reported Warrants, the Reporting Persons cannot exercise any of the Reported Warrants to the extent the Reporting Persons would beneficially own, after any such exercise, more than 9.99% of the outstanding shares of Common Stock (the "9.99% Blocker") and the percentage set forth in Row (11) of the cover page for each of the Reporting Persons gives effect to the 9.99% Blocker. Consequently, at this time, the Reporting Persons are not able to exercise all of such Reported Warrants due to the 9.99% Blocker.
(b)
Percent of class:
9.9%
(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 Account, which is an account of Point72 Associates II, LLC, 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
