Xilio Therapeutics filing: OrbiMed reports 9.99% stake

Xilio Therapeutics reported that OrbiMed Advisors LLC and affiliated OrbiMed Capital GP X LLC disclosed beneficial ownership positions in Common Stock.

Rhea-AI Filing Summary

Xilio Therapeutics reported that OrbiMed Advisors LLC and affiliated OrbiMed Capital GP X LLC disclosed beneficial ownership positions in Common Stock. The filing shows OrbiMed Advisors beneficially owns 642,000 shares (9.99%) and OrbiMed GP beneficially owns 481,500 shares (7.49%) as disclosed with a reporting date of 03/31/2026. The filing states the positions arise upon conversion of warrants in the aggregate and that investment and voting power is exercised through a management committee.

Insights

Institutional Ownership Analyst

Large passive stake disclosed by OrbiMed group, structured via warrant conversion.

OrbiMed Advisors reports 642,000 shares equal to 9.99% of Xilio Therapeutics Common Stock and OrbiMed GP reports 481,500 shares equal to 7.49% as of 03/31/2026. The filing attributes these holdings to conversion of warrants held on behalf of other persons.

Cash‑flow treatment and exact beneficiaries are not itemized here; subsequent filings could clarify which funds or clients ultimately hold economic interest. The disclosure documents shared voting and dispositive power via a management committee.

Corporate Governance Specialist

Voting and dispositive power reported as shared through a committee; beneficial ownership disclaimers present.

The report states OrbiMed Advisors exercises investment and voting power through a management committee of named members who "disclaim beneficial ownership." This indicates control arrangements without direct personal holdings being claimed by the individuals.

Holder identity details and any change in voting arrangements would appear in future Schedule 13 filings if positions or ownership nature change.

Key Figures

Reporting date: 03/31/2026 OrbiMed Advisors beneficial ownership: 642,000 shares OrbiMed Capital GP X LLC beneficial ownership: 481,500 shares +2 more

5 metrics

Reporting date 03/31/2026 Schedule 13G reporting date

OrbiMed Advisors beneficial ownership 642,000 shares 9.99% of Common Stock

OrbiMed Capital GP X LLC beneficial ownership 481,500 shares 7.49% of Common Stock

CUSIP 28422T209 Common Stock CUSIP on filing

Signature date 05/15/2026 Schedule signed by Carl L. Gordon

Key Terms

Schedule 13G, Beneficial ownership, Shared dispositive power, Conversion of warrants

4 terms

Schedule 13G regulatory

"Item 1. (a) Name of issuer: Xilio Therapeutics, Inc."

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.

Beneficial ownership financial

"Item 4. (a) Amount beneficially owned: OrbiMed Advisors: 642,000"

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

Shared dispositive power regulatory

"(iv) Shared power to dispose or to direct the disposition of: 642,000"

Conversion of warrants financial

"The Reporting Persons hold 9.99% of the shares ... upon conversion of warrants in the aggregate"

FAQ

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

What stake did OrbiMed report in Xilio Therapeutics (XLO)?

OrbiMed Advisors reported 642,000 shares (9.99%) and OrbiMed Capital GP X LLC reported 481,500 shares (7.49%) as beneficial ownership in Common Stock on 03/31/2026.

Are these shares owned directly by OrbiMed principals?

The filing states investment and voting power is exercised by OrbiMed Advisors through a management committee; named committee members explicitly disclaim beneficial ownership of the reported shares.

How were these positions created according to the filing?

The report says the holdings reflect positions "upon conversion of warrants in the aggregate" held on behalf of other persons, indicating conversion as the proximate source of the shares.

Does the filing identify the ultimate beneficiaries of the shares?

The filing indicates shares are held on behalf of other persons but does not list individual beneficiaries; it notes the Reporting Persons hold the shares on behalf of others exceeding 5% thresholds.

What voting and dispositive powers are reported?

Both OrbiMed Advisors and OrbiMed GP report 0 sole voting/dispositive power and 642,000 / 481,500 shared voting and dispositive power, respectively, per the Schedule 13G entries.

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

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Accepted by SEC EDGAR 05/15/2026 - 04:38 PM Learn about SEC filing dates

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)

28422T209

(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): 28422T209

1

Names of Reporting Persons

ORBIMED ADVISORS 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 642,000.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 642,000.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

642,000.00

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)

9.99 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

CUSIP Number(s): 28422T209

1

Names of Reporting Persons

OrbiMed Capital GP X 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 481,500.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 481,500.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

481,500.00

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)

7.49 %

12

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Xilio Therapeutics, Inc.
(b)	Address of issuer's principal executive offices: 828 Winter Street Waltham, MA 02451
Item 2.
(a)	Name of person filing: OrbiMed Advisors LLC ("OrbiMed Advisors"), a limited liability company organized under the laws of Delaware and a registered investment adviser under the Investment Advisers Act of 1940, as amended. OrbiMed Capital GP X LLC ("OrbiMed GP" and together with OrbiMed Advisors, the "Reporting Persons"), a limited liability company organized under the laws of Delaware.
(b)	Address or principal business office or, if none, residence: 601 Lexington Avenue, 54th Floor New York, NY 10022
(c)	Citizenship: Please refer to Item 4 on each cover sheet for each filing person.
(d)	Title of class of securities: Common Stock, par value $0.0001 per share
(e)	CUSIP Number(s): 28422T209
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: OrbiMed Advisors: 642,000 OrbiMed GP: 481,500
(b)	Percent of class: OrbiMed Advisors: 9.99% OrbiMed GP: 7.49%
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: OrbiMed Advisors: 0 OrbiMed GP: 0
	(ii) Shared power to vote or to direct the vote: OrbiMed Advisors: 642,000 OrbiMed GP: 481,500
	(iii) Sole power to dispose or to direct the disposition of: OrbiMed Advisors: 0 OrbiMed GP: 0
	(iv) Shared power to dispose or to direct the disposition of: OrbiMed Advisors: 642,000 OrbiMed GP: 481,500
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. The Reporting Persons hold 9.99% of the shares of Common Stock upon conversion of warrants in the aggregate on behalf of other persons who have the right to receive or the power to direct the receipt of dividends from, or proceeds from the sale of, such securities. OrbiMed Advisors exercises investment and voting power over the shares of Common Stock through a management committee comprised of Carl L. Gordon, Sven H. Borho, and W. Carter Neild, each of whom disclaims beneficial ownership of the shares of Common Stock reported herein.
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.

ORBIMED ADVISORS LLC

Signature:	/s/ Carl L. Gordon
Name/Title:	Carl L. Gordon/Member
Date:	05/15/2026

OrbiMed Capital GP X LLC

Signature:	/s/ Carl L. Gordon
Name/Title:	Carl L. Gordon/Member of OrbiMed Advisors LLC
Date:	05/15/2026