ADAR1 reports 5.4% stake in Adagio Medical

ADAR1 Capital Management, LLC and Daniel Schneeberger report beneficial ownership of Adagio Medical Holdings, Inc. common stock.

Rhea-AI Filing Summary

ADAR1 Capital Management, LLC and Daniel Schneeberger report beneficial ownership of Adagio Medical Holdings, Inc. common stock. They disclose shared voting and dispositive power over 1,205,447 shares of common stock, representing 5.4% of the class, based on 22,210,459 shares outstanding as of June 30, 2026.

The reported stake consists of 1,054,697 shares held by ADAR1 Partners, LP and 150,750 shares held by Spearhead Insurance Solutions IDF, LLC. Additional potential equity exposure is excluded from this figure: 1,733,980 shares underlying milestone warrants and 500,000 shares issuable upon conversion of 13% senior secured convertible notes held by ADAR1 Partners, LP, plus 185,138 shares underlying milestone warrants held by Spearhead Insurance Solutions IDF, LLC, all subject to a 4.99% beneficial ownership limitation.

Key Figures

Beneficially owned shares: 1,205,447 shares Ownership percentage: 5.4% Shares held by ADAR1 Partners, LP: 1,054,697 shares +5 more

8 metrics

Beneficially owned shares 1,205,447 shares Common stock over which ADAR1 Capital Management and Daniel Schneeberger report shared voting and dispositive power

Ownership percentage 5.4% Percent of Adagio Medical common stock class based on 22,210,459 shares outstanding as of June 30, 2026

Shares held by ADAR1 Partners, LP 1,054,697 shares Portion of beneficially owned Adagio Medical common stock held by ADAR1 Partners, LP

Shares held by Spearhead Insurance Solutions IDF, LLC 150,750 shares Portion of beneficially owned Adagio Medical common stock held by Spearhead Insurance Solutions IDF, LLC

Shares outstanding 22,210,459 shares Adagio Medical common stock outstanding as of June 30, 2026, per Form 10-Q

Milestone warrant shares (ADAR1 Partners, LP) 1,733,980 shares Common stock underlying milestone warrants excluded due to 4.99% beneficial ownership limitation

Convertible note shares 500,000 shares Common stock issuable upon conversion of 13% senior secured convertible notes held by ADAR1 Partners, LP, excluded from beneficial ownership

Milestone warrant shares (Spearhead) 185,138 shares Common stock underlying milestone warrants held by Spearhead Insurance Solutions IDF, LLC, excluded due to 4.99% cap

Key Terms

beneficially own, milestone warrants, 13% senior secured convertible notes, beneficial ownership limitations, +1 more

5 terms

beneficially own financial

"may be deemed to indirectly beneficially own securities held by ADAR1 Partners"

Beneficially own means having the economic rights and risks of a security—such as the right to receive dividends, sell the shares, or profit from price changes—whether or not your name appears on the official share register. Think of it like renting a car: you use it and reap the benefits even if the title lists someone else. Investors care because beneficial ownership determines who truly controls value, must be disclosed under securities rules, and can signal potential influence or trading activity that affects a stock’s price.

milestone warrants financial

"Excludes 1,733,980 shares of Common Stock underlying milestone warrants held by ADAR1 Partners"

Milestone warrants are rights that let holders buy a company’s stock only if specific goals—such as regulatory approvals, sales targets, or project completions—are met. Think of them as a coupon that only becomes usable when the company hits agreed checkpoints; they matter to investors because they create contingent value and potential share dilution, and they signal which outcomes the company and its backers consider most important.

13% senior secured convertible notes financial

"500,000 shares of Common Stock issuable upon conversion of 13% senior secured convertible notes"

beneficial ownership limitations financial

"the exchange and exercise of which are subject to 4.99% beneficial ownership limitations"

Beneficial ownership limitations are rules or contractual caps that restrict how much of a company’s stock an individual or entity can be treated as owning or controlling for legal, regulatory or corporate-governance purposes. They matter to investors because such limits affect voting power, reporting obligations, takeover risk and the ability to increase a stake — like an elevator weight limit or a lane divider that prevents any one car from taking over the whole road.

control person financial

"Mr. Schneeberger is filing this as a control person in respect of shares"

A control person is an individual or entity that can significantly influence a company’s decisions and direction through ownership, voting power, or contractual rights—think of them as the captain who can steer the ship. Investors care because a control person’s choices affect corporate strategy, board appointments, and transactions that can raise or lower a stock’s value, and they often carry additional legal responsibilities and disclosure requirements to protect other shareholders.

FAQ

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

What percentage of Adagio Medical Holdings, Inc. (ADGM) does ADAR1 Capital Management report owning?

ADAR1 Capital Management and Daniel Schneeberger report 5.4% beneficial ownership of Adagio Medical Holdings, Inc. common stock, based on 22,210,459 shares outstanding as of June 30, 2026, as disclosed in the company’s Form 10-Q.

How many Adagio Medical (ADGM) shares are beneficially owned by ADAR1-related entities?

The Reporting Persons disclose beneficial ownership of 1,205,447 Adagio Medical common shares, including 1,054,697 shares held by ADAR1 Partners, LP and 150,750 shares held by Spearhead Insurance Solutions IDF, LLC.

What additional Adagio Medical (ADGM) shares are excluded due to ownership limits?

Excluded are 1,733,980 shares underlying milestone warrants and 500,000 shares from 13% senior secured convertible notes held by ADAR1 Partners, plus 185,138 warrant shares held by Spearhead, all subject to 4.99% beneficial ownership limitations.

Why does Daniel Schneeberger report beneficial ownership in Adagio Medical (ADGM)?

Daniel Schneeberger, a citizen of Switzerland, files as a control person because, as manager of ADAR1 Capital Management, LLC, he may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP and Spearhead Insurance Solutions IDF, LLC.

What voting and dispositive powers are reported over Adagio Medical (ADGM) shares?

Both ADAR1 Capital Management and Daniel Schneeberger report 0 sole voting and dispositive power and 1,205,447 shared voting and shared dispositive power over Adagio Medical common stock, reflecting their indirect holdings through ADAR1 Partners and Spearhead.

What is the basis for the ownership percentage reported for Adagio Medical (ADGM)?

The 5.4% ownership figure is calculated using 22,210,459 Adagio Medical common shares outstanding as of June 30, 2026, as reported in the company’s Form 10-Q for the quarter ended June 30, 2026.

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

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Available on EDGAR 08/14/2026 - 05:04 PM Accepted by SEC EDGAR 08/14/2026 - 05:04 PM Learn about SEC filing dates

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

ADAR1 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

TEXAS

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,205,447.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,205,447.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,205,447.00

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)

5.4 %

12

Type of Reporting Person (See Instructions)

IA, OO

Comment for Type of Reporting Person: Includes (i) 1,054,697 shares of common stock, par value $0.0001 per share ("Common Stock") held by ADAR1 Partners, LP, and (ii) 150,750 shares of Common Stock held by Spearhead Insurance Solutions IDF, LLC as of June 30, 2026. Excludes 1,733,980 shares of Common Stock underlying milestone warrants held by ADAR1 Partners, LP, 500,000 shares of Common Stock issuable upon conversion of 13% senior secured convertible notes held by ADAR1 Partners, LP, and 185,138 shares of Common Stock underlying milestone warrants held by Spearhead Insurance Solutions IDF, LLC, the exchange and exercise of which are subject to 4.99% beneficial ownership limitations. As the investment manager of ADAR1 Partners, LP and as the sub-advisor of Spearhead Insurance Solutions IDF, LLC, ADAR1 Capital Management, LLC may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP and Spearhead Insurance Solutions IDF, LLC. Based on 22,210,459 shares of Common Stock of Adagio Medical Holdings, Inc. (the "Issuer") outstanding as of June 30, 2026, reported in the Issuer's Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2026, filed with the Securities and Exchange Commission on August 11, 2026.

SCHEDULE 13G

CUSIP Number(s): 00534B100

1

Names of Reporting Persons

Daniel Schneeberger

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

SWITZERLAND

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,205,447.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,205,447.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,205,447.00

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)

5.4 %

12

Type of Reporting Person (See Instructions)

HC, IN

Comment for Type of Reporting Person: Includes (i) 1,054,697 shares of common stock, par value $0.0001 per share ("Common Stock") held by ADAR1 Partners, LP, and (ii) 150,750 shares of Common Stock held by Spearhead Insurance Solutions IDF, LLC as of June 30, 2026. Excludes 1,733,980 shares of Common Stock underlying milestone warrants held by ADAR1 Partners, LP, 500,000 shares of Common Stock issuable upon conversion of 13% senior secured convertible notes held by ADAR1 Partners, LP, and 185,138 shares of Common Stock underlying milestone warrants held by Spearhead Insurance Solutions IDF, LLC, the exchange and exercise of which are subject to 4.99% beneficial ownership limitations. As the manager of ADAR1 Capital Management, LLC, Mr. Schneeberger may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP and Spearhead Insurance Solutions IDF, LLC. Based on 22,210,459 shares of Common Stock of Adagio Medical Holdings, Inc. (the "Issuer") outstanding as of June 30, 2026, reported in the Issuer's Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2026, filed with the Securities and Exchange Commission on August 11, 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 Schedule is being filed on behalf of each of the following persons (each, a "Reporting Person" and collectively, the "Reporting Persons"): (i) ADAR1 Capital Management, LLC ("ADAR1 Capital Management"); and (ii) Daniel Schneeberger ("Mr. Schneeberger").
(b)	Address or principal business office or, if none, residence: The address of the principal business office of each of the Reporting Persons is 3503 Wild Cherry Drive, Building 9, Austin, Texas 78738.
(c)	Citizenship: (i) ADAR1 Capital Management is a Texas limited liability company; and (ii) Mr. Schneeberger is a citizen of Switzerland.
(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: The information contained on the cover pages of this Schedule 13G is incorporated herein by reference.
(b)	Percent of class: The information contained on the cover pages of this Schedule 13G is incorporated herein by reference.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: The information contained on the cover pages of this Schedule 13G is incorporated herein by reference.
	(ii) Shared power to vote or to direct the vote: The information contained on the cover pages of this Schedule 13G is incorporated herein by reference.
	(iii) Sole power to dispose or to direct the disposition of: The information contained on the cover pages of this Schedule 13G is incorporated herein by reference.
	(iv) Shared power to dispose or to direct the disposition of: The information contained on the cover pages of this Schedule 13G 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.
	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.
	If a parent holding company has filed this schedule, pursuant to Rule 13d-1(b)(ii)(G), so indicate under Item 3(g) and attach an exhibit stating the identity and the Item 3 classification of the relevant subsidiary. If a parent holding company has filed this schedule pursuant to Rule 13d-1(c) or Rule 13d-1(d), attach an exhibit stating the identification of the relevant subsidiary. Mr. Schneeberger is filing this Schedule 13G as a control person in respect of shares beneficially owned by ADAR1 Capital Management, an investment adviser as described in SS 240.13d-1(b)(1)(ii)(E).
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.

ADAR1 Capital Management, LLC

Signature:	/s/ Daniel Schneeberger
Name/Title:	Daniel Schneeberger, Manager
Date:	08/14/2026

Daniel Schneeberger

Signature:	/s/ Daniel Schneeberger
Name/Title:	Daniel Schneeberger, in his individual capacity
Date:	08/14/2026