Filed Pursuant to Rule 424(b)(3)
Registration No. 333-284266
PROSPECTUS SUPPLEMENT
To Prospectus dated February 7, 2025
Up to 12,146,988 Shares of Common Stock
Up to 9,098,727 Shares of Common Stock Issuable
Upon Exercise of Warrants
Up to 46,717,980 Shares of Common Stock Issuable
Upon Conversion of Notes
Adagio Medical Holdings, Inc.
This prospectus supplement
updates and supplements the information contained in the prospectus dated February 7, 2025 (as may be supplemented or amended from time
to time, the “Prospectus”), which forms part of our registration statement on Form S-1 (File No. 333-284266) with the information
contained in our Current Report on Form 8-K that was filed with the Securities and Exchange Commission on December 16, 2025 (the “Current
Report”). Accordingly, we have attached the Current Report to this prospectus supplement.
The Prospectus and this prospectus
supplement relate to the offer, sale or other disposition from time to time of up to 67,963,695 shares of our common stock, $0.0001 par
value per share (the “Common Stock”), by the selling stockholders named in the Prospectus or their permitted transferees (collectively,
the “selling stockholders”), consisting of (i) up to 7,951,913 shares of Common Stock (excluding the shares of Common Stock
underlying the PIPE Warrants (as defined below)) (the “PIPE Shares”) and 110,000 shares of Common Stock (the “Registration
Delay Shares”) issued pursuant to the terms of the Convert Waivers (as defined below), (ii) up to 670,000 shares of Common Stock
issuable upon exercise of pre-funded warrants to purchase shares (the “Pre-Funded Warrant Shares”) of Common Stock, with an
exercise price of $0.01 per share (the “Pre-Funded Warrants”), (iii) up to 7,528,727 shares of Common Stock (the “PIPE
Warrant Shares”) issuable upon exercise of warrants to purchase shares of Common Stock, with an exercise price of $10.00 per share
(the “PIPE Warrants”), in each of cases (i) through (iii), issued pursuant to those certain amended and restated subscription
agreements, dated July 31, 2024 (the “Subscription Agreements”), by and among us, ARYA Sciences Acquisition Corp IV, a Cayman
Islands exempted company (“ARYA”), and certain selling stockholders named therein (the “PIPE Investors”) at an
effective price of approximately $7.10 per PIPE Share and/or Pre-Funded Warrant, (iv) up to 46,717,980 shares of Common Stock (excluding
the shares of Common Stock underlying the Convert Warrants (as defined below)) (the “Convertible Note Shares”) issuable upon
the conversion of those certain 13% senior secured convertible notes, with a conversion price of $10.00 per share, subject to adjustment
as provided in the Convertible Security Subscription Agreement (as defined below), (the “Convert Notes”), (v) up to 900,000
shares of Common Stock (the “Convert Warrant Shares”) issuable upon exercise of warrants to purchase shares of Common Stock,
with an exercise price of $24.00 per share, subject to adjustment as provided in such warrants (the “Convert Warrants” and,
together with the PIPE Warrants, the “Warrants”), in each of cases (iv) and (v), issued pursuant to that certain securities
purchase agreement, dated February 13, 2024, by and among us and certain investors named therein (the “Convert Investors”),
and any assignment thereunder (the “Convertible Security Subscription Agreement”), and that certain note purchase agreement,
dated February 13, 2024, by and among us, Adagio Medical, Inc., a Delaware corporation, and Perceptive Life Sciences Master Fund, Ltd,
a Cayman Islands exempted company (the “2024 Bridge Financing Note Subscription Agreement”), (vi) up to 2,354,100 shares issued
to ARYA Sciences Holdings IV, a Cayman Islands exempted company (the “Sponsor”), consisting of 499,000 shares of Common Stock
that were initially issued to Sponsor in a private placement as Class A ordinary shares of ARYA at a price of $10.00 per share and exchanged
for shares of Common Stock at Closing (as defined below) (the “Sponsor Class A Conversion Shares”), 1,500,000 shares of Common
Stock that were initially issued to Sponsor as Class B ordinary shares of ARYA at an effective price of approximately $0.007 per share
and exchanged for shares of Common Stock at Closing (the “Sponsor Class B Conversion Shares”), and 355,100 shares of Common
Stock that were originally issued to Sponsor as Class A ordinary shares of ARYA upon the conversion of certain convertible promissory
notes issued by ARYA at an effective price of $10.00 per share and exchanged for shares of Common Stock at Closing (the “Sponsor
Working Capital Shares”), (vii) up to 582,475 shares of Common Stock, consisting of 492,475 shares of Common Stock issued to certain
of our affiliates as consideration in connection with the Business Combination (as defined below) at an equity consideration value of
approximately $9.23 per share and 30,000 shares of Common Stock issued to each of Michael Henderson, Todd Wider and Leslie Trigg (collectively,
the “Independent ARYA Directors”), which were originally issued as Class B ordinary shares of ARYA, valued at approximately
$0.007 per share, (viii) up to 1,147,500 shares of Common Stock issuable to the Sponsor that are subject to share trigger price vesting
and will vest if, prior to the tenth anniversary of the Closing, the post-Closing share price of Common Stock equals or exceeds $24.00
per share for any 20 trading days within any 30 trading day period (the “Share Trigger Price Vesting”), which were originally
issued as Class B ordinary shares of ARYA, valued at approximately $0.007 per share and exchanged for shares of Common Stock at Closing;
and (ix) 1,000 shares of Common Stock issuable upon exercise of certain stock options assumed by us in connection with the consummation
of the Business Combination held by our Chief Operating Officer with an exercise price of $1.67 per share.
You should read this prospectus
supplement in conjunction with the Prospectus. This prospectus supplement is qualified by reference to the Prospectus except to the extent
that the information in this prospectus supplement supersedes the information contained in the Prospectus. This prospectus supplement
is not complete without, and may not be delivered or utilized except in connection with, the Prospectus. If there is any inconsistency
between the information in the Prospectus and this prospectus supplement, you should rely on the information in this prospectus supplement.
Terms used in this prospectus supplement but not defined herein shall have the meanings given to such terms in the Prospectus.
Our Common Stock is listed
on The Nasdaq Capital Market under the symbol “ADGM”. On December 16, 2025, the last reported sales price of our Common Stock
was $1.18 per share.
We are an “emerging
growth company” as defined under U.S. federal securities laws and, as such, have elected to comply with reduced public company reporting
requirements. This prospectus complies with the requirements that apply to an issuer that is an emerging growth company.
Investing in our securities
involves a high degree of risk. You should review carefully the risks and uncertainties described in the section titled “Risk Factors”
beginning on page 15 of the prospectus, and under similar headings in any amendments or supplements to the prospectus.
Neither the Securities
and Exchange Commission nor any state securities commission has approved or disapproved of these securities, or passed upon the accuracy
or adequacy of the prospectus. Any representation to the contrary is a criminal offense.
The date of this prospectus supplement is December
16, 2025.
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 8-K
CURRENT REPORT
Pursuant to Section 13 or 15(d) of
the Securities Exchange Act of 1934
Date of Report (Date of earliest event reported):
December 15, 2025
ADAGIO MEDICAL HOLDINGS, INC.
(Exact name of registrant as specified in its
charter)
| Delaware |
001-42199 |
99-1151466 |
| (State or other jurisdiction of incorporation) |
(Commission File Number) |
(I.R.S. Employer Identification No.) |
|
26051 Merit Circle, Suite 102
Laguna Hills, CA |
|
92653 |
| (Address of principal executive offices) |
|
(Zip Code) |
(949) 348-1188
(Registrant’s telephone number, including
area code)
Not Applicable
(Former name or former address, if changed since
last report)
Check the appropriate box below if the Form 8-K
filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:
| ¨ |
Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) |
| |
|
| ¨ |
Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) |
| |
|
| ¨ |
Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) |
| |
|
| ¨ |
Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) |
Securities registered pursuant to Section 12(b) of
the Act:
| Title of each class |
Trading
Symbol(s) |
Name of each exchange
on which registered |
| Common Stock, par value $0.0001 per share |
ADGM |
The Nasdaq Stock Market LLC |
Indicate by check mark whether the registrant
is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 or Rule 12b-2 of the Securities Exchange
Act of 1934.
Emerging growth
company x
If an emerging growth
company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or
revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐
Item 5.07 Submission of Matters to a Vote of Security Holders.
On December 15, 2025, Adagio Medical Holdings,
Inc. (the “Company”) held its 2025 Annual Meeting of Stockholders (the “Annual Meeting”). The stockholders considered
two proposals, each of which is described in more detail in the Company’s definitive proxy statement filed with the Securities and
Exchange Commission on November 4, 2025 (the “Proxy Statement”). Of the 21,179,637 shares outstanding as of the record date,
13,862,436 shares, or 65.45%, were present or represented by proxy at the Annual Meeting. The final results for each of the matters submitted
to the stockholders at the Annual Meeting are as follows:
Proposal
No 1: Election of two nominees to serve as directors until the 2028 annual meeting of stockholders and until their respective
successors are elected and qualified. The votes were cast as follows:
| |
For |
|
Withheld |
|
Broker Non-Votes |
| Todd Usen |
12,915,589 |
|
19,972 |
|
926,875 |
| James L. Cox, M.D. |
11,610,366 |
|
1,325,195 |
|
926,875 |
Both nominees were elected.
Proposal No 2: Ratification of the appointment of WithumSmith+Brown,
PC as independent registered public accounting firm for the fiscal year ending December 31, 2025. The votes were cast as follows:
| For |
|
Against |
|
Abstain |
|
Broker Non-Votes |
| 13,407,336 |
|
352,547 |
|
102,553 |
|
— |
SIGNATURE
Pursuant to the requirements
of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto
duly authorized.
Dated: December 16, 2025
| |
Adagio Medical Holdings, Inc. |
| |
|
| |
By: |
/s/ Deborah Kaster |
| |
Name: |
Deborah Kaster |
| |
Title: |
Chief Financial Officer |
