X4 Pharma CFO sells shares to cover tax bill

X4 Pharmaceuticals Chief Financial Officer David Kirske sold 8,543 shares of common stock in an open-market transaction.

Rhea-AI Filing Summary

X4 Pharmaceuticals Chief Financial Officer David Kirske sold 8,543 shares of common stock in an open-market transaction. The shares were sold at a weighted average price of $4.2641 per share, in multiple trades between $4.21 and $4.31.

According to the filing, the sale was made to cover a personal income tax obligation arising from the settlement of a restricted stock unit award. After this transaction, Kirske directly owns 167,750 shares of X4 Pharmaceuticals common stock, including 96,627 shares represented by restricted stock units.

Insider Trade Summary

Net Seller: 8,543 shares

Net Sell 1 txn

Insider KIRSKE DAVID

Role Chief Financial Officer

Sold 8,543 shs ($36K)

Type	Security	Shares	Price	Value
Sale	Common Stock	8,543	$4.2641	$36K

Holdings After Transaction: Common Stock — 167,750 shares (Direct)

Footnotes (3)

1. F1. Sale of shares to cover personal income tax obligation upon settlement of restricted stock unit award.
2. F2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $4.21 to $4.31, inclusive. The Reporting Person undertakes to provide the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.
3. F3. Of the shares of common stock reported, 96,627 shares represent restricted stock units.

Key Figures

Shares sold: 8,543 shares Average sale price: $4.2641 per share Price range: $4.21–$4.31 per share +2 more

5 metrics

Shares sold 8,543 shares Open-market sale on 2026-06-30

Average sale price $4.2641 per share Weighted average sale price

Price range $4.21–$4.31 per share Individual transaction prices within the sale

Shares owned after 167,750 shares Direct holdings following the transaction

RSUs included in holdings 96,627 shares Restricted stock units within total direct holdings

Key Terms

open-market sale, restricted stock units, weighted average price, income tax obligation

4 terms

open-market sale financial

"Sale in open market or private transaction"

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

restricted stock units financial

"Of the shares of common stock reported, 96,627 shares represent restricted stock units."

Restricted stock units are a type of company reward where employees are promised shares of stock, but they only fully own these shares after meeting certain conditions, like staying with the company for a set time. They matter because they can become valuable assets and are often used to motivate employees to help the company succeed.

weighted average price financial

"The price reported in Column 4 is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

income tax obligation financial

"Sale of shares to cover personal income tax obligation upon settlement of restricted stock unit award."

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What did X4 Pharmaceuticals (XFOR) CFO David Kirske report in this Form 4?

David Kirske reported an open-market sale of 8,543 X4 Pharmaceuticals common shares. The filing explains the sale was executed to cover a personal income tax obligation tied to the settlement of a restricted stock unit award.

How many X4 Pharmaceuticals (XFOR) shares did the CFO sell and at what price?

The CFO sold 8,543 common shares at a weighted average price of $4.2641. The trades occurred in multiple transactions with individual prices ranging from $4.21 to $4.31 per share, as detailed in the filing footnotes.

Why did the X4 Pharmaceuticals (XFOR) CFO sell shares in this transaction?

The sale was made to cover a personal income tax obligation triggered by the settlement of a restricted stock unit award. This indicates the transaction was related to compensation and tax requirements rather than a discretionary reduction of his overall equity position.

How many X4 Pharmaceuticals (XFOR) shares does the CFO own after the sale?

After the reported sale, the CFO directly owns 167,750 shares of X4 Pharmaceuticals common stock. This total includes 96,627 shares that represent restricted stock units, which are equity awards that typically vest over time under specified conditions.

What does the weighted average price mean in the X4 Pharmaceuticals (XFOR) Form 4?

The weighted average price of $4.2641 reflects multiple trades executed between $4.21 and $4.31. The filing notes the insider will provide full details of the number of shares sold at each individual price within that range upon request.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Accepted by SEC EDGAR 07/01/2026 - 04:23 PM Learn about SEC filing dates

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
Estimated average burden
hours per response:			0.5

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 MASSACHUSETTS 02134

(City) (State) (Zip)

UNITED STATES

(Country)

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

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
06/30/2026

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	06/30/2026		S(1)		8,543	D	$4.2641(2)	167,750(3)	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

Explanation of Responses:

1. Sale of shares to cover personal income tax obligation upon settlement of restricted stock unit award.

2. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions ranging from $4.21 to $4.31, inclusive. The Reporting Person undertakes to provide the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

3. Of the shares of common stock reported, 96,627 shares represent restricted stock units.

Remarks:

	/s/ Mitch Buckley, attorney-in-fact	07/01/2026
	** 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)