[Form 4] X4 Pharmaceuticals, Inc. Insider Trading Activity

Rhea-AI Filing Summary

X4 Pharmaceuticals insider filings show equity awards to Chief Financial Officer David Kirske. The Form 4 reports 193,254 restricted stock units granted on 08/14/2025 and two stock option grants recorded on 08/12/2025 and 08/14/2025 covering 1,073,249 and 352,800 underlying shares respectively. The options have exercise prices of $1.42 and $3.14 with expiration dates of 08/12/2035 and 08/14/2035. Vesting schedules are described: RSUs vest one-third on 02/12/2026 then quarterly over 12 months subject to continued service and shareholder approval; options vest 50% on 02/12/2026 then monthly over 12 months with certain performance-based immediate vesting for half if milestones are met before 02/12/2026.

Positive

• Compensatory grants disclosed: 193,254 RSUs and options covering 1,426,049 underlying shares were granted and reported
• Transparent vesting terms: RSUs and options include explicit time-based and performance-based vesting schedules
• Exercise prices and expirations provided: Options at $1.42 and $3.14 expiring in 2035 are fully specified

Negative

• None.

Insights

Securities Analyst

TL;DR: CFO received RSUs and two option grants totaling 1,426,049 underlying shares, with multi-stage time and performance vesting.

The Form 4 documents compensatory equity awards to the reporting person, including 193,254 RSUs and options for 1,073,249 and 352,800 shares. Exercise prices are explicitly stated at $1.42 and $3.14, with both options expiring in 2035. Vesting is time-based with specified milestone-triggered acceleration for part of one option grant. This is a standard executive compensation disclosure and does not include any transfers or sales of shares.

Corporate Governance Expert

TL;DR: Disclosure provides clear vesting and approval conditions; RSU vesting contingent on 2026 shareholder approval.

The filing clearly ties part of the RSU vesting to shareholder approval at the 2026 annual meeting and outlines performance conditions for option acceleration. These terms are governance-relevant because they require continued service and a formal shareholder vote for full vesting. The record includes the attorney-in-fact signature and standard Form 4 mechanics.

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

OMB APPROVAL

OMB Number:			3235-0287
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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^*

KIRSKE DAVID

(Last) (First) (Middle)

C/O X4 PHARMACEUTICALS INC.

61 N BEACON STREET, 4TH FLOOR

(Street)

BOSTON MA 02134

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
X4 Pharmaceuticals, Inc [ XFOR ]

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

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

3. Date of Earliest Transaction (Month/Day/Year)
08/12/2025

4. 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 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	08/14/2025		A		193,254(1)	A	$0	193,254	D

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
Stock Option (right to buy)	$1.42	08/12/2025		A		1,073,249		(2)	08/12/2035	Common Stock	1,073,249	$0	1,073,249	D
Stock Option (right to buy)	$3.14	08/14/2025		A		352,800		(2)	08/14/2035	Common Stock	352,800	$0	352,800	D

Explanation of Responses:

1. 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.

2. 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.

Remarks:

	/s/ Brian Bowersox, Attorney-In-Fact	08/14/2025
	** 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 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.

FAQ

What equity awards did David Kirske receive according to the XFOR Form 4?

The Form 4 reports 193,254 restricted stock units and two stock option grants covering 1,073,249 and 352,800 underlying shares.

What are the exercise prices and expiration dates for the options reported on XFOR Form 4?

The Form 4 lists option exercise prices of $1.42 (expiring 08/12/2035) and $3.14 (expiring 08/14/2035).

When do the RSUs and options vest according to the filing?

RSUs vest one-third on 02/12/2026 then quarterly over 12 months subject to service and shareholder approval; options vest 50% on 02/12/2026 then monthly over 12 months with half subject to immediate vesting upon certain milestones before 02/12/2026.

Is the RSU grant subject to shareholder approval in the XFOR filing?

Yes. The RSU grant is contingent upon approval of the grant at the issuer's 2026 Annual Meeting of Stockholders.

What is the reporting date of the earliest transaction on the Form 4?

The earliest transaction date shown on the Form 4 is 08/12/2025.