[SCHEDULE 13G] Adagio Medical Holdings, Inc SEC Filing

Rhea-AI Filing Summary

Adage Capital Management, L.P., together with individuals Robert Atchinson and Phillip Gross, reported beneficial ownership of 821,261 shares of Adagio Medical Holdings, Inc. common stock, representing 5.34% of the class. The percentage was calculated using 15,381,565 shares outstanding as of May 7, 2025, per the company quarterly report filed May 15, 2025. The Schedule 13G shows shared voting and shared dispositive power over all 821,261 shares and includes a certification that the securities were acquired and are held in the ordinary course of business and not to influence control. The filing lists the issuer office in Laguna Hills, CA, and includes a joint filing agreement as Exhibit 99.1.

Positive

• Reported beneficial ownership exceeds 5%, at 821,261 shares (5.34%), meeting materiality thresholds that require public disclosure
• Filing is on Schedule 13G with a certification that the shares are held in the ordinary course and not to influence control, indicating passive intent

Negative

• None.

Insights

Financial Analyst

TL;DR: Adage reports a passive 5.34% stake (821,261 shares) in Adagio, disclosed on Schedule 13G.

The filing documents a >5% position held by Adage Capital Management, L.P., with shared voting and dispositive power over 821,261 shares, calculated on 15,381,565 shares outstanding as of May 7, 2025. Because this is a Schedule 13G with a certification that the stake is held in the ordinary course and not to influence control, it is presented as a passive, reportable ownership position rather than an active control attempt.

Corporate Governance Expert

TL;DR: The Schedule 13G filing signals a reportable, passive substantial holder with shared authority over the position.

The statement names Adage Capital Management, L.P. and two individuals as reporting persons and shows shared voting and dispositive power for all reported shares. The filing includes the required certification and a joint filing agreement (Exhibit 99.1). The use of Schedule 13G and the explicit certification indicate the reporting persons characterize the position as passive under applicable rules.

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)

06/30/2025

(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

Adage Capital Management, L.P.

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 821,261.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 821,261.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

821,261.00

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)

5.34 %

12

Type of Reporting Person (See Instructions)

IA, PN

SCHEDULE 13G

CUSIP No. 00534B100

1

Names of Reporting Persons

Robert Atchinson

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 821,261.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 821,261.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

821,261.00

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)

5.34 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

CUSIP No. 00534B100

1

Names of Reporting Persons

Phillip Gross

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 821,261.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 821,261.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

821,261.00

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)

5.34 %

12

Type of Reporting Person (See Instructions)

HC, IN

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 by: (i) Adage Capital Management, L.P., a Delaware limited partnership ("ACM"), as the investment manager of Adage Capital Partners, L.P., a Delaware limited partnership ("ACP"), with respect to the shares of common stock, par value $0.0001 per share ("Common Stock") of Adagio Medical Holdings, Inc., a Delaware corporation (the "Company") directly held by ACP; (ii) Robert Atchinson ("Mr. Atchinson"), as (1) managing member of Adage Capital Advisors, L.L.C., a limited liability company organized under the laws of the State of Delaware ("ACA"), managing member of Adage Capital Partners GP, L.L.C., a limited liability company organized under the laws of the State of Delaware ("ACPGP"), general partner of ACP and (2) managing member of Adage Capital Partners LLC, a Delaware limited liability company ("ACPLLC"), general partner of ACM, with respect to the shares of Common Stock directly held by ACP; and (iii) Phillip Gross ("Mr. Gross"), as (1) managing member of ACA, managing member of ACPGP and (2) managing member of ACPLLC, general partner of ACM, with respect to the shares of Common Stock directly held by ACP. The foregoing persons are hereinafter sometimes collectively referred to as the "Reporting Persons." Any disclosures herein with respect to persons other than the Reporting Persons are made on information and belief after making inquiry to the appropriate party. The filing of this statement should not be construed in and of itself as an admission by any Reporting Person as to beneficial ownership of the securities reported herein.
(b)	Address or principal business office or, if none, residence: The address of the business office of each of the Reporting Persons is 200 Clarendon Street, 52nd Floor, Boston, Massachusetts 02116.
(c)	Citizenship: ACM is a limited partnership organized under the laws of the State of Delaware. Messrs. Gross and Atchinson are citizens of the United States.
(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 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 15,381,565 shares of Common Stock outstanding as of May 7, 2025, as reported in the Company's Quarterly Report on Form 10-Q for the quarterly period ended March 31, 2025, filed with the Securities and Exchange Commission on May 15, 2025.
(b)	Percent of class: 5.34%
(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.
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).
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.

Adage Capital Management, L.P.

Signature:	/s/ Robert Atchinson
Name/Title:	By: Adage Capital Partners LLC, its General Partner, By: Robert Atchinson, its Managing Member
Date:	08/12/2025

Robert Atchinson

Signature:	/s/ Robert Atchinson
Name/Title:	Robert Atchinson, individually
Date:	08/12/2025

Phillip Gross

Signature:	/s/ Phillip Gross
Name/Title:	Phillip Gross, individually
Date:	08/12/2025

Exhibit Information

Exhibit 99.1: Joint Filing Agreement

FAQ

What stake in Adagio Medical (ADGM) did Adage report?

Adage reported beneficial ownership of 821,261 shares, equal to 5.34% of Adagio Medical common stock.

How was the 5.34% ownership calculated for ADGM?

The percentage uses an aggregate of 15,381,565 shares outstanding as of May 7, 2025, per the company's quarterly report filed May 15, 2025.

Which reporting persons filed the Schedule 13G for ADGM?

The filing was made by Adage Capital Management, L.P. and two individuals: Robert Atchinson and Phillip Gross.

Does the filing indicate Adage seeks to influence control of ADGM?

No. The Schedule 13G includes a certification that the securities were acquired and are held in the ordinary course of business and not to change or influence control.

What voting and dispositive powers are reported?

The filing reports 0 shares with sole voting or dispositive power and 821,261 shares with shared voting and shared dispositive power.