[Form 3] Adagio Medical Holdings, Inc. Initial Statement of Beneficial Ownership

Rhea-AI Filing Summary

Adagio Medical Holdings, Inc. (ADGM) Form 3 shows Deborah Kaster, the company's Chief Financial Officer and a director, reporting an initial equity award consisting of an employee stock option covering 728,000 shares of Common Stock exercisable on 04/01/2035 at an exercise price of $0.84 per share. The grant vests 25% on the one-year anniversary of April 1, 2025, with the remaining shares vesting in 36 equal monthly installments thereafter.

The Form 3 lists the event date as 09/05/2025 and is signed on 09/30/2025. This filing is an initial statement of beneficial ownership under Section 16 and discloses the reported derivative security (an option) owned directly by the reporting person.

Positive

• Initial Option Grant Disclosed: Reporting person holds an employee stock option for 728,000 common shares
• Clear Vesting Schedule: 25% vests after one year (April 1, 2025) with remaining shares vesting in 36 equal monthly installments
• Full Exercise Terms Provided: Exercise price of $0.84 and exercisable date 04/01/2035 are disclosed

Negative

• None.

Insights

Corporate Governance Expert

TL;DR: Routine Section 16 disclosure of a CFO option grant with multi-year vesting schedule; governance disclosure appears complete.

The filing documents an initial stock option award to the CFO who also serves as a director, with clear vesting terms and exercise price disclosed. As a standard Section 16 filing, it fulfills insider reporting obligations by identifying the derivative instrument, exercisability date, and vesting schedule. No other disclosures or amendments are present.

Compensation Analyst

TL;DR: A single long-dated option grant for 728,000 shares with staged vesting aligns executive pay with multi-year performance or retention.

The option's size and 10-year term (exercise date listed as 04/01/2035) and phased vesting (25% after one year, then monthly over three years) indicate a retention-focused award. The filing provides necessary structural details—amount, exercise price, vesting cadence—but contains no performance conditions or other settlement terms.

SEC Form 3

FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person^*

Kaster Deborah

(Last) (First) (Middle)

C/O ADAGIO MEDICAL HOLDINGS, INC.

26051 MERIT CIRCLE, STE. 102

(Street)

LAGUNA HILLS CA 92653

(City) (State) (Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
09/05/2025

3. Issuer Name and Ticker or Trading Symbol
Adagio Medical Holdings, Inc. [ ADGM ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

	Director		10% Owner
X	Officer (give title below)		Other (specify below)
	Chief Financial Officer

5. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4)	2. Amount of Securities Beneficially Owned (Instr. 4)	3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	4. Nature of Indirect Beneficial Ownership (Instr. 5)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Employee Stock Option (right to buy)	(1)	04/01/2035	Common Stock	728,000	$0.84	D

Explanation of Responses:

1. Twenty-five percent (25%) of Option shares will vest on the one-year anniversary of April 1, 2025, with the remaining shares vesting in thirty-six (36) equal monthly installments thereafter.

	/s/ Deborah Kaster	09/30/2025
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 5 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

FAQ

What did Deborah Kaster report on Form 3 for ADGM?

She reported an employee stock option for 728,000 shares of common stock with an exercise price of $0.84 and an exercisable date of 04/01/2035.

When does the option vest according to the Form 3?

The option vests 25% on April 1, 2026 (one-year anniversary of April 1, 2025) and the remainder vests in 36 equal monthly installments thereafter.

What is Deborah Kaster's relationship to Adagio Medical Holdings (ADGM)?

The filing identifies her as a Director and the company's Chief Financial Officer.

What are the dates shown on the Form 3?

The event date is listed as 09/05/2025 and the form is signed on 09/30/2025.

Does the Form 3 disclose any indirect ownership or other derivative instruments?

No; the filing discloses a direct employee stock option only and does not list other indirect ownership or additional derivative securities.