Sio Capital (ADGM) discloses 1,288,461 Adagio Medical shares

Rhea-AI Filing Summary

Sio Capital Management, LLC reported a significant ownership position in Adagio Medical Holdings, Inc. common stock. As of December 31, 2025, Sio beneficially owned 1,288,461 shares, representing 6.08% of Adagio’s common stock, based on 21,179,637 shares outstanding as of November 10, 2025.

Sio, a Delaware limited liability company and registered investment adviser, has shared voting and dispositive power over these shares through affiliated funds. The position is certified as being held in the ordinary course of business and not for the purpose of changing or influencing control of Adagio Medical Holdings.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Adagio Medical Holdings, Inc.

(Name of Issuer)

Common Stock, par value, $0.0001 per share

(Title of Class of Securities)

00534B100

(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. 00534B100

1

Names of Reporting Persons

Sio Capital Management, 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 1,288,461.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,288,461.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,288,461.00

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)

6.08 %

12

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person: 1 As of December 31, 2025, Sio Capital Management, LLC beneficially owned 1,288,461 shares of Common Stock with shared voting power and shared dispositive power. 2 Based upon 21,179,637 Common Shares outstanding as of November 10, 2025, as disclosed by the Issuer's 10-Q on November 12, 2025.

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Adagio Medical Holdings, Inc.
(b)	Address of issuer's principal executive offices: 26051 Merit Circle, Suite 102, Laguna Hills, CA 92653
Item 2.
(a)	Name of person filing: This Statement is filed on behalf of Sio Capital Management, LLC (the "Reporting Person" or "Sio") Sio is a registered investment adviser to certain affiliated funds that directly hold the shares of Common Stock to which this statement relates for the benefit of their respective investors, and in such capacity Sio has voting and dispositive power over such shares.
(b)	Address or principal business office or, if none, residence: 600 Third Avenue, 2nd Floor New York, New York 10016
(c)	Citizenship: Sio is a Delaware limited liability company.
(d)	Title of class of securities: Common Stock, par value, $0.0001 per share
(e)	CUSIP No.: 00534B100
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: 1,288,461
(b)	Percent of class: 6.08 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 0
	(ii) Shared power to vote or to direct the vote: 1,288,461 - Refer to footnote 3 3 Sio and Sio GP, LLC (the "GP") act as investment advisor and general partner, respectively, to various clients that are the record owners of the Common Stock reported on this Schedule 13G. Because Sio's investment discretion with respect to such clients is subject to oversight by the GP, the GP may be deemed to be the beneficial owner of the Common Stock of the Issuer owned by such clients. In addition, both Sio and the GP are controlled by Michael Castor. As such, he may be deemed to control the voting and dispositive decisions with respect to, and therefore be the beneficial owner of, the shares of Common Stock reported on this Schedule 13G. Neither the filing of this Schedule 13G nor any of its contents shall be deemed to constitute an admission by the GP or Michael Castor that such person is the beneficial owner of any of the equity securities referred to herein for purposes of Section 13(d) of the Exchange Act, or for any other purpose, and such beneficial ownership is expressly disclaimed.
	(iii) Sole power to dispose or to direct the disposition of: 0
	(iv) Shared power to dispose or to direct the disposition of: 1,288,461 - Refer to footnote 3 3 Sio and Sio GP, LLC (the "GP") act as investment advisor and general partner, respectively, to various clients that are the record owners of the Common Stock reported on this Schedule 13G. Because Sio's investment discretion with respect to such clients is subject to oversight by the GP, the GP may be deemed to be the beneficial owner of the Common Stock of the Issuer owned by such clients. In addition, both Sio and the GP are controlled by Michael Castor. As such, he may be deemed to control the voting and dispositive decisions with respect to, and therefore be the beneficial owner of, the shares of Common Stock reported on this Schedule 13G. Neither the filing of this Schedule 13G nor any of its contents shall be deemed to constitute an admission by the GP or Michael Castor that such person is the beneficial owner of any of the equity securities referred to herein for purposes of Section 13(d) of the Exchange Act, or for any other purpose, and such beneficial ownership is expressly disclaimed.
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 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.

Sio Capital Management, LLC

Signature:	/s/ Jin W. Lee
Name/Title:	Chief Compliance Officer
Date:	02/02/2026

FAQ

What ownership stake does Sio Capital report in Adagio Medical Holdings (ADGM)?

Sio Capital Management, LLC reports beneficial ownership of 1,288,461 Adagio Medical Holdings common shares, representing 6.08% of the company. This percentage is based on 21,179,637 shares outstanding as of November 10, 2025, as disclosed in Adagio’s quarterly report.

How many Adagio Medical (ADGM) shares does Sio Capital beneficially own?

Sio Capital beneficially owns 1,288,461 shares of Adagio Medical Holdings common stock. These shares are held through affiliated funds for their investors, with Sio exercising voting and dispositive power in its role as registered investment adviser to those funds.

What percentage of Adagio Medical’s common stock is held by Sio Capital?

Sio Capital’s reported position represents 6.08% of Adagio Medical Holdings’ outstanding common stock. This ownership percentage is calculated using 21,179,637 common shares outstanding as of November 10, 2025, as disclosed in Adagio’s Form 10-Q filing.

Does Sio Capital seek to influence control of Adagio Medical (ADGM)?

Sio Capital certifies that its Adagio Medical shares were acquired and are held in the ordinary course of business. It further states they were not acquired or held to change or influence control of Adagio, nor in connection with any control-related transaction.

Who ultimately oversees the Adagio Medical shares reported by Sio Capital?

Sio Capital and Sio GP, LLC act as investment adviser and general partner to clients that directly own the Adagio shares. The filing notes both entities are controlled by Michael Castor, who may be deemed to control voting and investment decisions, though such beneficial ownership is expressly disclaimed.

What type of entity is Sio Capital in the Adagio Medical Schedule 13G?

Sio Capital Management, LLC is described as a Delaware limited liability company and a registered investment adviser. It files the Schedule 13G on behalf of affiliated funds that directly hold Adagio Medical common stock, over which Sio has voting and dispositive authority.