RA Capital and affiliated persons report beneficial ownership of Adagio Medical common stock equal to 1,200,000 shares, representing 7.2% of the outstanding class as of June 30, 2025. The filing clarifies that 1,140,000 of those shares are issuable upon exercise of warrants held directly by RA Capital Healthcare Fund, L.P., and 60,000 are issuable upon exercise of warrants held by RA Capital Nexus Fund II, L.P. RA Capital, Dr. Kolchinsky and Mr. Shah note delegated voting and dispositive powers for the funds and file this Amendment to correct a prior clerical omission of the warrant-based holdings.
Positive
Corrected disclosure of warrant-derived common shares improves transparency
Material stake disclosed: aggregate 1,200,000 shares representing 7.2% of the company, providing clarity to investors
Majority of position tied to warrants that are stated as immediately exercisable (1,140,000 shares held by the healthcare fund)
Negative
Clerical omission in the prior amendment resulted in an initial underreporting of beneficial ownership
Delegation of voting/dispositive power to the investment adviser means economic ownership and control are separated, which can raise governance questions for some investors
Insights
TL;DR: The amendment discloses a >7% aggregate position via warrants, a material ownership stake but not an overt change of control.
The 1,200,000-share position equals 7.2% of the combined share count used by the filers, primarily comprised of 1,140,000 warrant-inflated shares held by the healthcare fund and 60,000 by Nexus Fund II. This disclosure matters because holdings above 5% generally attract investor attention and regulatory reporting obligations. The amendment corrects a clerical omission, improving transparency about contingent common shares from warrants that are immediately exercisable. There is no indication in the filing that the holders seek to influence control; the report maintains disclaimers and delegated voting arrangements.
TL;DR: Correcting omitted warrant-based holdings is important for governance transparency, though the filing shows no intent to change control.
The filing clarifies beneficial ownership attributable to warrants and reconfirms delegated voting/dispositive authority to the adviser. That structure is common for investment-manager relationships but the previous omission of warrant-derived shares is a disclosure lapse that was remedied. From a governance perspective, stakeholders should note the reported stake passes the 5% notification threshold and that the filers expressly disclaim group status and any current intent to influence control.
What stake does RA Capital report in Adagio Medical (ADGM)?
The Reporting Persons disclose an aggregate beneficial position of 1,200,000 shares, equal to 7.2% of the class as reported in this amendment.
How many of the reported shares are exercisable warrants?
1,140,000 shares are issuable upon exercise of warrants held directly by RA Capital Healthcare Fund, L.P., and 60,000 shares are issuable upon exercise of warrants held by RA Capital Nexus Fund II, L.P.
Does the filing indicate an intent to change or influence control of ADGM?
No. The certification states the securities were not acquired for the purpose of changing control and the Reporting Persons disclaim any such intent.
Why was this amendment filed?
The amendment corrects a clerical error in a prior Schedule 13G amendment that inadvertently omitted the beneficial ownership of shares underlying certain warrants.
What percentage of Adagio Medical does the healthcare fund specifically represent?
RA Capital Healthcare Fund, L.P. reports beneficial ownership of 1,140,000 shares, representing 6.9% of the class based on the filer’s calculations.
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No. 4)
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
RA 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
1,200,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,200,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,200,000.00
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)
7.2 %
12
Type of Reporting Person (See Instructions)
IA, PN
Comment for Type of Reporting Person: This Amendment No. 4 to Schedule 13G (this "Amendment") is being filed to correct Amendment No. 3 to Schedule 13G by RA Capital Management, L.P., Peter Kolchinsky, Rajeev Shah and RA Capital Healthcare Fund, L.P. (the "Reporting Persons"), filed with the Securities and Exchange Commission on August 14, 2025. Due to a clerical error, Amendment No. 3 inadvertently omitted the beneficial ownership of shares of Common Stock underlying warrants held by each of RA Capital Healthcare Fund, L.P. and RA Capital Nexus Fund II, L.P. as of June 30, 2025. This Amendment is being filed to correct this clerical error and report the beneficial ownership of the Reporting Persons as of June 30, 2025.
SCHEDULE 13G
CUSIP No.
00534B100
1
Names of Reporting Persons
Peter Kolchinsky
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
1,200,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,200,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,200,000.00
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)
7.2 %
12
Type of Reporting Person (See Instructions)
HC, IN
Comment for Type of Reporting Person: This Amendment No. 4 to Schedule 13G (this "Amendment") is being filed to correct Amendment No. 3 to Schedule 13G by RA Capital Management, L.P., Peter Kolchinsky, Rajeev Shah and RA Capital Healthcare Fund, L.P. (the "Reporting Persons"), filed with the Securities and Exchange Commission on August 14, 2025. Due to a clerical error, Amendment No. 3 inadvertently omitted the beneficial ownership of shares of Common Stock underlying warrants held by each of RA Capital Healthcare Fund, L.P. and RA Capital Nexus Fund II, L.P. as of June 30, 2025. This Amendment is being filed to correct this clerical error and report the beneficial ownership of the Reporting Persons as of June 30, 2025.
SCHEDULE 13G
CUSIP No.
00534B100
1
Names of Reporting Persons
Rajeev Shah
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
1,200,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,200,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,200,000.00
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)
7.2 %
12
Type of Reporting Person (See Instructions)
HC, IN
Comment for Type of Reporting Person: This Amendment No. 4 to Schedule 13G (this "Amendment") is being filed to correct Amendment No. 3 to Schedule 13G by RA Capital Management, L.P., Peter Kolchinsky, Rajeev Shah and RA Capital Healthcare Fund, L.P. (the "Reporting Persons"), filed with the Securities and Exchange Commission on August 14, 2025. Due to a clerical error, Amendment No. 3 inadvertently omitted the beneficial ownership of shares of Common Stock underlying warrants held by each of RA Capital Healthcare Fund, L.P. and RA Capital Nexus Fund II, L.P. as of June 30, 2025. This Amendment is being filed to correct this clerical error and report the beneficial ownership of the Reporting Persons as of June 30, 2025.
SCHEDULE 13G
CUSIP No.
00534B100
1
Names of Reporting Persons
RA Capital Healthcare Fund, 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
1,140,000.00
7
Sole Dispositive Power
0.00
8
Shared Dispositive Power
1,140,000.00
9
Aggregate Amount Beneficially Owned by Each Reporting Person
1,140,000.00
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)
6.9 %
12
Type of Reporting Person (See Instructions)
PN
Comment for Type of Reporting Person: This Amendment No. 4 to Schedule 13G (this "Amendment") is being filed to correct Amendment No. 3 to Schedule 13G by RA Capital Management, L.P., Peter Kolchinsky, Rajeev Shah and RA Capital Healthcare Fund, L.P. (the "Reporting Persons"), filed with the Securities and Exchange Commission on August 14, 2025. Due to a clerical error, Amendment No. 3 inadvertently omitted the beneficial ownership of shares of Common Stock underlying warrants held by each of RA Capital Healthcare Fund, L.P. and RA Capital Nexus Fund II, L.P. as of June 30, 2025. This Amendment is being filed to correct this clerical error and report the beneficial ownership of the Reporting Persons as of June 30, 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:
The names of the persons filing this report (collectively, the "Reporting Persons") are:
RA Capital Management, L.P. ("RA Capital")
Peter Kolchinsky
Rajeev Shah
RA Capital Healthcare Fund, L.P. (the "Fund")
The Reporting Persons expressly disclaim status as a "group" for purposes of this Schedule 13G.
(b)
Address or principal business office or, if none, residence:
The address of the principal business office of each of the Reporting Persons is:
c/o RA Capital Management, L.P., 200 Berkeley Street, 18th Floor, Boston MA 02116
(c)
Citizenship:
RA Capital and the Fund are Delaware limited partnerships.
Dr. Kolchinsky and Mr. Shah are United States citizens.
(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:
Row 9 of each Reporting Person's cover page to this Schedule 13G sets forth the aggregate number of shares of securities of the Issuer beneficially owned by such Reporting Person as of June 30, 2025 and is incorporated by reference.
The Reporting Persons' ownership of the Issuer's securities includes (i) 1,140,000 shares of common stock issuable upon the exercise of immediately exercisable warrants (the "Warrants") directly held by the Fund, and (ii) 60,000 shares of common stock issuable upon the exercise of immediately exercisable Warrants directly held by RA Capital Nexus Fund II, L.P. (the "Nexus Fund II").
RA Capital Healthcare Fund GP, LLC is the general partner of the Fund and RA Capital Nexus Fund II GP, LLC is the general partner of the Nexus Fund II. The general partner of RA Capital is RA Capital Management GP, LLC, of which Dr. Kolchinsky and Mr. Shah are the controlling persons. RA Capital serves as investment adviser for each of the Fund and the Nexus Fund II and may be deemed a beneficial owner, for purposes of Section 13(d) of the Act, of any securities of the Issuer held by the Fund or the Nexus Fund II. Each of the Fund and the Nexus Fund II has delegated to RA Capital the sole power to vote and the sole power to dispose of all securities held in its portfolio, including the shares of the Issuer's common stock reported herein. Because each of the Fund and the Nexus Fund II has divested itself of voting and investment power over the reported securities it holds and may not revoke that delegation on less than 61 days' notice, each of the Fund and the Nexus Fund II disclaims beneficial ownership of the securities it holds for purposes of Section 13(d) of the Act and therefore disclaims any obligation to report ownership of the reported securities under Section 13(d) of the Act. As managers of RA Capital, Dr. Kolchinsky and Mr. Shah may be deemed beneficial owners, for purposes of Section 13(d) of the Act, of any securities of the Issuer beneficially owned by RA Capital. RA Capital, Dr. Kolchinsky, and Mr. Shah disclaim beneficial ownership of the securities reported in this Schedule 13G other than for the purpose of determining their obligations under Section 13(d) of the Act, and the filing of this Schedule 13G shall not be deemed an admission that either RA Capital, Dr. Kolchinsky, or Mr. Shah is the beneficial owner of such securities for any other purpose.
(b)
Percent of class:
Row 11 of each Reporting Person's cover page to this Schedule 13G sets forth the percentages of securities of the Issuer beneficially owned by such Reporting Person as of June 30, 2025 and is incorporated by reference. The percentage set forth in Row 11 of each Reporting Person's cover page is based upon the sum of: (i) 15,381,565 shares of the Issuer's common stock outstanding as of June 30, 2025, as reported in the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (the "SEC") on August 14, 2025 and (ii) 1,200,000 shares of common stock issuable upon the exercise of the Warrants.
(c)
Number of shares as to which the person has:
(i) Sole power to vote or to direct the vote:
Row 5 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person as of June 30, 2025 and is incorporated by reference.
(ii) Shared power to vote or to direct the vote:
Row 6 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person as of June 30, 2025 and is incorporated by reference.
(iii) Sole power to dispose or to direct the disposition of:
Row 7 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person as of June 30, 2025 and is incorporated by reference.
(iv) Shared power to dispose or to direct the disposition of:
Row 8 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person as of June 30, 2025 and is incorporated 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.
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 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.
RA Capital Management, L.P.
Signature:
/s/ Peter Kolchinsky
Name/Title:
By Peter Kolchinsky, Authorized Signatory
Date:
08/26/2025
Peter Kolchinsky
Signature:
/s/ Peter Kolchinsky
Name/Title:
Peter Kolchinsky
Date:
08/26/2025
Rajeev Shah
Signature:
/s/ Rajeev Shah
Name/Title:
Rajeev Shah
Date:
08/26/2025
RA Capital Healthcare Fund, L.P.
Signature:
/s/ Peter Kolchinsky
Name/Title:
By RA Capital Healthcare Fund GP, LLC, its General Partner, By Peter Kolchinsky, Manager
Date:
08/26/2025
Exhibit Information
Exhibit 99.1 Joint Filing Agreement (incorporated by reference to Exhibit 99.1 to Schedule 13G/A filed on May 15, 2025)
