Sio Capital trims Adagio Medical (ADGM) holding to 3.15% under 5% threshold

Rhea-AI Filing Summary

Sio Capital Management, LLC, a Delaware limited liability company and registered investment adviser, reported beneficial ownership of 698,989 shares of Adagio Medical Holdings, Inc. common stock as of June 30, 2026. These shares represent 3.15% of Adagio’s common stock, based on 22,210,459 shares outstanding as of May 8, 2026.

Sio has shared voting and dispositive power over all 698,989 shares through affiliated funds for which it serves as investment adviser, and no sole voting or dispositive power. The filing notes that Sio GP, LLC and Michael Castor may be deemed beneficial owners but expressly disclaim such beneficial ownership. The position is reported as ownership of 5 percent or less of the class.

Key Figures

Beneficial ownership shares: 698,989 shares Percent of class: 3.15% Shares outstanding: 22,210,459 shares +5 more

8 metrics

Beneficial ownership shares 698,989 shares Shares of Adagio Medical common stock beneficially owned by Sio Capital as of June 30, 2026

Percent of class 3.15% Percentage of Adagio Medical common stock represented by Sio Capital’s 698,989 shares

Shares outstanding 22,210,459 shares Adagio Medical common shares outstanding as of May 8, 2026, used to calculate ownership percentage

Sole voting power 0 shares Number of shares over which Sio Capital has sole power to vote or direct the vote

Shared voting power 698,989 shares Number of shares over which Sio Capital has shared voting power

Sole dispositive power 0 shares Number of shares over which Sio Capital has sole dispositive power

Shared dispositive power 698,989 shares Number of shares over which Sio Capital has shared power to dispose or direct disposition

Signature date 07/15/2026 Date the Schedule 13G/A amendment was signed by the Chief Compliance Officer

Key Terms

beneficial owner, shared dispositive power, shared voting power, investment adviser, +2 more

6 terms

beneficial owner financial

"the GP may be deemed to be the beneficial owner of the Common Stock"

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.

shared dispositive power financial

"Shared Dispositive Power 698,989.00"

shared voting power financial

"Shared Voting Power 698,989.00"

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.

investment adviser financial

"Sio is a registered investment adviser to certain affiliated funds"

An investment adviser is a person or firm that professionally manages money and gives recommendations about buying, selling, or holding investments. Like a financial coach or guide, they have a legal duty to act in a client's best financial interest, so their advice, fees and potential conflicts can directly affect returns and risk — making their role important for investors who want informed, accountable help with portfolios.

Section 13(d) of the Exchange Act regulatory

"for purposes of Section 13(d) of the Exchange Act, or for any other purpose"

Schedule 13G regulatory

"referred to herein for purposes of Section 13(d) of the Exchange Act"

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.

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

See more from StockTitan in Google Search and AI answers. Adds StockTitan as a preferred source · opens Google

Add on Google Not now

Available on EDGAR 07/28/2026 - 04:49 PM Accepted by SEC EDGAR 07/28/2026 - 04:49 PM Learn about SEC filing dates

FAQ

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

Sio Capital reports beneficial ownership of 698,989 shares of Adagio Medical common stock, representing 3.15% of the outstanding shares, based on 22,210,459 shares outstanding as of May 8, 2026.

Does Sio Capital have sole or shared voting power over ADGM shares?

Sio Capital reports 0 shares with sole voting power and 698,989 shares with shared voting power. It similarly reports 0 shares with sole dispositive power and 698,989 with shared dispositive power.

Why is Adagio Medical (ADGM) reported as 5 percent or less owned by Sio Capital?

The filing states Sio Capital’s beneficial ownership is 3.15% of Adagio Medical’s common stock, which is explicitly categorized as ownership of 5 percent or less of the class under Schedule 13G reporting.

How does Sio Capital hold its ADGM position according to the Schedule 13G/A?

Sio Capital advises affiliated funds that directly hold the 698,989 ADGM shares for their investors. In this advisory capacity, Sio has voting and dispositive power over these shares, all on a shared basis.

Who may be deemed beneficial owners of Sio Capital’s ADGM shares?

The filing notes that Sio GP, LLC and Michael Castor may be deemed beneficial owners due to control relationships, but it expressly disclaims beneficial ownership by them for Section 13(d) and other purposes.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

(Amendment No. 1)

Adagio Medical Holdings, Inc.

(Name of Issuer)

Common Stock, par value, $0.0001 per share

(Title of Class of Securities)

00534B100

(CUSIP Number)

06/30/2026

(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): 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 698,989.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 698,989.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

698,989.00

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)

3.15 %

12

Type of Reporting Person (See Instructions)

IA

Comment for Type of Reporting Person: 1 As of June 30, 2026, Sio Capital Management, LLC beneficially owned 698,989 shares of Common Stock with shared voting power and shared dispositive power. 2 Based upon 22,210,459 Common Shares outstanding as of May 8, 2026, as disclosed by the Issuer's 10-Q on May 12, 2026.

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: 698,989
(b)	Percent of class: 3.15 %
(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: 698,989 - 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: 698,989 - 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.
	Ownership of 5 percent or less of a class
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:	07/15/2026