[Form 4] X4 Pharmaceuticals, Inc Insider Trading Activity

Rhea-AI Filing Summary

X4 Pharmaceuticals (XFOR) filed a Form 4 reporting a stock option grant to its Chief Financial Officer, David Kirske. The filing lists 1,552,769 stock options with an exercise price of $1.42 and an expiration date of 08/12/2035.

According to the disclosure, the options were granted on 08/12/2025 and were subject to a performance-based vesting condition that was satisfied on 10/29/2025. One third of the shares subject to the option will vest on 08/12/2026, with the remainder vesting in equal monthly installments over the following 24 months, contingent on continued service. Following the reported transaction, 1,552,769 derivative securities are shown as beneficially owned, held directly.

Insights

Equity Compensation Analyst

Large CFO option grant with performance condition met; routine.

The filing records a grant of 1,552,769 stock options at an exercise price of $1.42, initially granted on 08/12/2025. The performance-based condition was satisfied on 10/29/2025, which starts the vesting timetable but does not by itself create cash flow or dilution.

Vesting is time-based after the milestone: one third on 08/12/2026, then monthly vesting for 24 months, subject to continued service. The options expire on 08/12/2035. Actual impact depends on future exercises and service tenure; the filing lists ownership as Direct and a grant price of $0 for the derivative, consistent with standard awards.

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)
10/29/2025

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

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	10/29/2025		A		1,552,769		(1)	08/12/2035	Common Stock	1,552,769	$0	1,552,769	D

Explanation of Responses:

1. Represents stock options granted to the Reporting Person on August 12, 2025, which were subject to a performance-based vesting condition that was satisfied on October 29, 2025. One third of the shares subject to the option shall vest on August 12, 2026, with the remainder vesting in equal installments each successive month thereafter for a period of 24 months, subject to the Reporting Person continuing to provide services through each such date.

Remarks:

	/s/ David Kirske	10/31/2025
	** 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 did X4 Pharmaceuticals (XFOR) disclose in this Form 4?

A grant of 1,552,769 stock options to the CFO at an exercise price of $1.42, with an expiration date of 08/12/2035.

When was the performance condition for the XFOR CFO’s options satisfied?

The performance-based vesting condition was satisfied on 10/29/2025.

What is the vesting schedule for the XFOR CFO’s option grant?

One third vests on 08/12/2026, and the remainder vests in equal monthly installments over the next 24 months, subject to continued service.

How many derivative securities are beneficially owned after the reported transaction?

1,552,769 derivative securities are reported as beneficially owned, held directly.

What is the exercise price and type of security reported for XFOR?

It is a stock option (right to buy) with an exercise price of $1.42 per share.

What is the role of the reporting person at X4 Pharmaceuticals (XFOR)?

The reporting person is the Chief Financial Officer.