ATN International (ATNI) chair sees 25K PSUs vest, 9,412 shares withheld for taxes

Rhea-AI Filing Summary

ATN International executive chairman Michael T. Prior reported equity compensation activity tied to performance-based awards. Performance-based restricted stock units for 25,000 shares of common stock vested based on relative total shareholder return versus the Russell 2000, resulting in shares being issued at 58% of the target amount.

Of the vested shares, 9,412 common shares were withheld by the company to cover Prior’s tax obligations at a price of $24.18 per share. Following these transactions, he directly owns 583,404 common shares and also has additional indirect holdings as trustee of several family trusts.

SEC Form 4

FORM 4

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

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

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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Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

PRIOR MICHAEL T

(Last) (First) (Middle)

C/O ATN INTERNATIONAL, INC.

500 CUMMINGS CENTER

(Street)

BEVERLY MASSACHUSETTS 01915

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
ATN International, Inc. [ ATNI ]

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

X	Director		10% Owner
	Officer (give title below)	X	Other (specify below)
			EXECUTIVE CHAIRMAN

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
03/07/2026

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

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

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

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	03/07/2026		M		14,500(1)	A	(2)	592,816	D
Common Stock	03/07/2026		F		6,430(3)	D	$24.18	586,386	D
Common Stock	03/07/2026		F		2,982(4)	D	$24.18	583,404	D
Common Stock								128,847	I	Trustee of Lauren S. Prior 2013 Trust
Common Stock								8,141	I	Trustee of JP 2018 Trust
Common Stock								7,741	I	Trustee of WP 2015 Trust
Common Stock								8,041	I	Trustee of RP 2014 Trust
Common Stock								7,982	I	Trustee of Prior Family Trust 2019

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Performance-Based Restricted Stock Units	$0	03/07/2026		M			25,000	03/07/2026	03/07/2026	Common Stock	25,000	$0	0	D

Explanation of Responses:

1. Common stock issued upon vesting of performance-based RSU ("PSU") based on the achievement of pre-established relative total shareholder return ("TSR") goals that were set by the Compensation Committee of the Issuer's Board of Directors, based on comparing the Issuer's TSR relative to the TSR of the Russell 2000 Index, using the average closing price of the shares for the 40 days before and including each of the first and last trading days of the applicable performance period, which ended on March 7, 2026. The aggregate number of shares issued is 58% of the target number of PSU shares previously reported.

2. Refer to existing footnote (1)

3. Represents shares withheld by the Company for payment of Mr. Prior's tax obligation arising from the vesting of previously granted Performance Stock Units in the existing footnote (1).

4. Represents shares withheld by the Company for payment of Mr. Prior's tax obligation arising from the vesting of previously granted Restricted Stock Units.

	/s/ Michael T. Prior	03/27/2026
	** 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 4 (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.
* Form 4: SEC 1474 (03-26)

FAQ

What insider transactions did ATN International (ATNI) report for Michael T. Prior?

ATN International reported that executive chairman Michael T. Prior had 25,000 performance-based restricted stock units vest into common shares. Related common shares were then withheld by the company to satisfy tax obligations, reflecting routine equity compensation and tax-settlement activity rather than open-market trading.

How many ATN International (ATNI) shares does Michael T. Prior hold after this Form 4?

After the reported transactions, Michael T. Prior directly holds 583,404 ATN International common shares. The filing also lists additional indirect holdings through several family trusts where he serves as trustee, providing further exposure that is reported separately from his direct ownership position.

What triggered the vesting of Michael T. Prior’s performance-based RSUs at ATN International (ATNI)?

The vesting was triggered by pre-established relative total shareholder return goals. These compared ATN International’s shareholder return to the Russell 2000 Index over a defined performance period, using 40-day average closing prices, and resulted in 58% of the target performance-based unit shares being issued.

How many ATN International (ATNI) shares were withheld for Michael T. Prior’s taxes?

The company withheld 9,412 ATN International common shares to cover Michael T. Prior’s tax obligations. These include 6,430 shares and 2,982 shares withheld at a price of $24.18 per share, tied to the vesting of performance-based and restricted stock unit awards previously granted.

Does this ATN International (ATNI) Form 4 show any open-market buying or selling?

The Form 4 shows derivative exercises and tax-withholding dispositions, but no open-market purchases or sales. Shares arose from vesting of performance-based and restricted stock units, and some were withheld by the company to satisfy tax liabilities rather than being traded in the open market.

What types of equity awards are involved in Michael T. Prior’s ATN International (ATNI) filing?

The filing involves performance-based restricted stock units linked to relative total shareholder return and previously granted restricted stock units. These awards converted into common stock upon vesting, with a portion of the resulting shares withheld by ATN International to pay Michael T. Prior’s associated tax obligations.