David Kirske - Aug 12, 2025 Form 4 Insider Report for X4 Pharmaceuticals, Inc (XFOR)

Role: Chief Financial Officer
Signature: /s/ Brian Bowersox, Attorney-In-Fact
Stock symbol: XFOR
Transactions as of: Aug 12, 2025
Transactions value $: $0
Form type: 4
Date filed: 8/14/2025, 08:31 PM
Previous filing: Jun 26, 2023
SEC: View on sec.gov

Reporting Owners (1)

Name	Relationship	Address	Signature	Signature date	CIK
KIRSKE DAVID	Chief Financial Officer	C/O X4 PHARMACEUTICALS INC., 61 N BEACON STREET, 4TH FLOOR, BOSTON	/s/ Brian Bowersox, Attorney-In-Fact	2025-08-14	0001276750

Transactions Table

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Ownership	Footnotes
transaction	XFOR	Common Stock	Award	$0	+193K		$0.00	193K	Aug 14, 2025	Direct	F1

Derivative Securities (e.g., puts, calls, warrants, options, convertible securities)

Type	Sym	Class	Transaction	Value $	Shares	Change %	* Price $	Shares After	Date	Underlying Class	Amount	Exercise Price	Ownership	Footnotes
transaction	XFOR	Stock Option (right to buy)	Award	$0	+1.07M		$0.00	1.07M	Aug 12, 2025	Common Stock	1.07M	$1.42	Direct	F2
transaction	XFOR	Stock Option (right to buy)	Award	$0	+353K		$0.00	353K	Aug 14, 2025	Common Stock	353K	$3.14	Direct	F2

* An asterisk sign (*) next to the price indicates that the price is likely invalid.

Explanation of Responses:

Id	Content
F1	Represents restricted stock units (RSUs) granted to the Reporting Person. One third of the RSUs shall vest on February 12, 2026, with the remainder vesting in equal installments in each successive quarter thereafter for a period of 12 months, subject to the Reporting Person continuing to provide services through each such date and contingent upon approval of the grant at the Issuer's 2026 Annual Meeting of Stockholders.
F2	One half of the shares subject to the option shall vest on February 12, 2026, with the remainder vesting in equal installments in each successive month thereafter for a period of 12 months, subject to the Reporting Person continuing to provide services through each such date; provided that one half of the shares subject to the option shall vest immediately upon achievement of certain performance-based milestones prior to February 12, 2026.

Content

Represents restricted stock units (RSUs) granted to the Reporting Person. One third of the RSUs shall vest on February 12, 2026, with the remainder vesting in equal installments in each successive quarter thereafter for a period of 12 months, subject to the Reporting Person continuing to provide services through each such date and contingent upon approval of the grant at the Issuer's 2026 Annual Meeting of Stockholders.

One half of the shares subject to the option shall vest on February 12, 2026, with the remainder vesting in equal installments in each successive month thereafter for a period of 12 months, subject to the Reporting Person continuing to provide services through each such date; provided that one half of the shares subject to the option shall vest immediately upon achievement of certain performance-based milestones prior to February 12, 2026.