[D] X4 Pharmaceuticals, Inc. SEC Filing

Rhea-AI Filing Summary

X4 Pharmaceuticals, Inc. filed a Form D reporting a Regulation D, Rule 506(b) exempt offering that raised $84,999,985, with the entire amount marked as sold and $0 remaining. The filing indicates the first sale date as 2025-08-13 and the issuer lists its principal place of business in Boston, Massachusetts. The offering included equity and options/warrants (and the securities to be acquired upon exercise) and reports 18 investors to date. Sales commissions are disclosed as $3,300,000 (estimated). The Form D was signed by Chief Legal Officer Natasha Thoren on behalf of the issuer.

Positive

• $84,999,985 total offering fully sold according to the filing
• Offering used Rule 506(b), indicating reliance on a common Reg D exemption
• Disclosure that $0 of proceeds were used to pay named officers, directors or promoters

Negative

• $3,300,000 in estimated sales commissions disclosed
• Filing reports 18 investors, which may suggest a concentrated investor base (as reported)

Insights

Securities Financial Analyst

TL;DR: X4 completed a Rule 506(b) exempt equity offering raising ~$85.0M, with $3.3M in disclosed commissions.

The filing documents a completed private offering under Rule 506(b) totaling $84,999,985, fully sold. It specifies equity and related option/warrant securities and lists 18 investors. The disclosed sales commissions of $3,300,000 are recorded as an estimated expense. The Form D indicates the offering was not intended to last more than one year and identifies Stifel, Nicolaus & Company as an associated broker-dealer. From a capital-formation perspective, the company secured near-$85M of proceeds via a compliant Reg D sale.

Corporate Governance Expert

TL;DR: Filing shows formal compliance with Reg D reporting and names executive signatory; no related-party proceeds reported.

The Form D identifies multiple executive officers and directors as related persons at the issuer's Boston address and certifies that $0 of the offering proceeds were used to pay named executives, directors, or promoters. The document is signed by the Chief Legal Officer, demonstrating an authorized filing. The disclosure of the associated broker-dealer and states of solicitation (including All States and Foreign/non-US) provides appropriate transparency for distribution channels.

The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete.
The reader should not assume that the information is accurate and complete.

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

Notice of Exempt Offering of Securities

OMB APPROVAL

OMB Number:			3235-0076
Estimated average burden
hours per response:			4.00

1. Issuer's Identity

CIK (Filer ID Number)

Previous Names

None

Entity Type

0001501697

Arsanis, Inc.

X	Corporation
	Limited Partnership
	Limited Liability Company
	General Partnership
	Business Trust
	Other (Specify)

Name of Issuer

X4 Pharmaceuticals, Inc

Jurisdiction of Incorporation/Organization

DELAWARE

Year of Incorporation/Organization

X	Over Five Years Ago
	Within Last Five Years (Specify Year)
	Yet to Be Formed

2. Principal Place of Business and Contact Information

Name of Issuer
X4 Pharmaceuticals, Inc
Street Address 1		Street Address 2
61 NORTH BEACON STREET		4TH FLOOR
City	State/Province/Country	ZIP/PostalCode	Phone Number of Issuer
BOSTON	MASSACHUSETTS	02134	857-529-8300

3. Related Persons

Last Name	First Name	Middle Name
Craig	Adam
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship: X Executive Officer X Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
Volpone	John
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship: X Executive Officer Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
Arbet-Engels	Christophe
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship: X Executive Officer Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
Baldry	Mark
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship: X Executive Officer Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
DiBiase	Mary
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship: X Executive Officer Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
Kirske	David
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship: X Executive Officer Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
Bridger	Gary	J.
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship: Executive Officer X Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
De Craecker	Francoise
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship: Executive Officer X Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
Stewart	Murray	W.
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship: Executive Officer X Director Promoter

Clarification of Response (if Necessary):

Last Name	First Name	Middle Name
Wyzga	Michael	S.
Street Address 1	Street Address 2
X4 PHARMACEUTICALS, INC.	61 NORTH BEACON STREET, 4TH FLOOR
City	State/Province/Country	ZIP/PostalCode
BOSTON	MASSACHUSETTS	02134

Relationship: Executive Officer X Director Promoter

Clarification of Response (if Necessary):

4. Industry Group

Agriculture

Banking & Financial Services

Commercial Banking

Insurance

Investing

Investment Banking

Pooled Investment Fund

Is the issuer registered as
an investment company under
the Investment Company
Act of 1940?

Yes No

Other Banking & Financial Services

Business Services

Energy

Coal Mining

Electric Utilities

Energy Conservation

Environmental Services

Oil & Gas

Other Energy

	Health Care
	X Biotechnology
	Health Insurance
	Hospitals & Physicians
	Pharmaceuticals
	Other Health Care
	Manufacturing
	Real Estate
	Commercial
	Construction
	REITS & Finance
	Residential
	Other Real Estate

Retailing

Restaurants

Technology

Computers

Telecommunications

Other Technology

Travel

Airlines & Airports

Lodging & Conventions

Tourism & Travel Services

Other Travel

Other

5. Issuer Size

Revenue Range		OR	Aggregate Net Asset Value Range
	No Revenues			No Aggregate Net Asset Value
	$1 - $1,000,000			$1 - $5,000,000
	$1,000,001 - $5,000,000			$5,000,001 - $25,000,000
	$5,000,001 - $25,000,000			$25,000,001 - $50,000,000
	$25,000,001 - $100,000,000			$50,000,001 - $100,000,000
	Over $100,000,000			Over $100,000,000
X	Decline to Disclose			Decline to Disclose
	Not Applicable			Not Applicable

6. Federal Exemption(s) and Exclusion(s) Claimed (select all that apply)

		Rule 504(b)(1) (not (i), (ii) or (iii))
		Rule 504 (b)(1)(i)
		Rule 504 (b)(1)(ii)
		Rule 504 (b)(1)(iii)
	X	Rule 506(b)
		Rule 506(c)
		Securities Act Section 4(a)(5)

Investment Company Act Section 3(c)

Section 3(c)(1) Section 3(c)(9)

Section 3(c)(2) Section 3(c)(10)

Section 3(c)(3) Section 3(c)(11)

Section 3(c)(4) Section 3(c)(12)

Section 3(c)(5) Section 3(c)(13)

Section 3(c)(6) Section 3(c)(14)

Section 3(c)(7)

7. Type of Filing

X	New Notice			Date of First Sale	2025-08-13				First Sale Yet to Occur
	Amendment

8. Duration of Offering

Does the Issuer intend this offering to last more than one year? Yes X No

9. Type(s) of Securities Offered (select all that apply)

X	Equity		Pooled Investment Fund Interests
	Debt		Tenant-in-Common Securities
X	Option, Warrant or Other Right to Acquire Another Security		Mineral Property Securities
X	Security to be Acquired Upon Exercise of Option, Warrant or Other Right to Acquire Security		Other (describe)

10. Business Combination Transaction

Is this offering being made in connection with a business combination transaction, such as a merger, acquisition or exchange offer? Yes X No

Clarification of Response (if Necessary):

11. Minimum Investment

Minimum investment accepted from any outside investor $0 USD

12. Sales Compensation

Recipient	Recipient CRD Number None
STIFEL, NICOLAUS & COMPANY, INCORPORATED	793
(Associated) Broker or Dealer X None	(Associated) Broker or Dealer CRD Number X None
None	None
Street Address 1	Street Address 2
501 NORTH BROADWAY
City	State/Province/Country	ZIP/Postal Code
ST. LOUIS	MISSOURI	63102
State(s) of Solicitation (select all that apply) Check "All States" or check individual States X All States	X Foreign/non-US

13. Offering and Sales Amounts

Total Offering Amount	$84,999,985	USD	or Indefinite
Total Amount Sold	$84,999,985	USD
Total Remaining to be Sold	$0	USD	or Indefinite

Clarification of Response (if Necessary):

14. Investors

Select if securities in the offering have been or may be sold to persons who do not qualify as accredited investors, and enter the number of such non-accredited investors who already have invested in the offering.

Regardless of whether securities in the offering have been or may be sold to persons who do not qualify as accredited investors, enter the total number of investors who already have invested in the offering:

18

15. Sales Commissions & Finder's Fees Expenses

Provide separately the amounts of sales commissions and finders fees expenses, if any. If the amount of an expenditure is not known, provide an estimate and check the box next to the amount.

Sales Commissions	$3,300,000	USD	Estimate
Finders' Fees	$0	USD	Estimate

Clarification of Response (if Necessary):

16. Use of Proceeds

Provide the amount of the gross proceeds of the offering that has been or is proposed to be used for payments to any of the persons required to be named as executive officers, directors or promoters in response to Item 3 above. If the amount is unknown, provide an estimate and check the box next to the amount.

$0

USD

Estimate

Clarification of Response (if Necessary):

Signature and Submission

Please verify the information you have entered and review the Terms of Submission below before signing and clicking SUBMIT below to file this notice.

Terms of Submission

In submitting this notice, each issuer named above is:

• Notifying the SEC and/or each State in which this notice is filed of the offering of securities described and undertaking to furnish them, upon written request, in the accordance with applicable law, the information furnished to offerees.*

• Irrevocably appointing each of the Secretary of the SEC and, the Securities Administrator or other legally designated officer of the State in which the issuer maintains its principal place of business and any State in which this notice is filed, as its agents for service of process, and agreeing that these persons may accept service on its behalf, of any notice, process or pleading, and further agreeing that such service may be made by registered or certified mail, in any Federal or state action, administrative proceeding, or arbitration brought against the issuer in any place subject to the jurisdiction of the United States, if the action, proceeding or arbitration (a) arises out of any activity in connection with the offering of securities that is the subject of this notice, and (b) is founded, directly or indirectly, upon the provisions of: (i) the Securities Act of 1933, the Securities Exchange Act of 1934, the Trust Indenture Act of 1939, the Investment Company Act of 1940, or the Investment Advisers Act of 1940, or any rule or regulation under any of these statutes, or (ii) the laws of the State in which the issuer maintains its principal place of business or any State in which this notice is filed.

• Certifying that, if the issuer is claiming a Regulation D exemption for the offering, the issuer is not disqualified from relying on Rule 504 or Rule 506 for one of the reasons stated in Rule 504(b)(3) or Rule 506(d).

Each Issuer identified above has read this notice, knows the contents to be true, and has duly caused this notice to be signed on its behalf by the undersigned duly authorized person.

For signature, type in the signer's name or other letters or characters adopted or authorized as the signer's signature.

Issuer	Signature	Name of Signer	Title	Date
X4 Pharmaceuticals, Inc	/s/ Natasha Thoren	Natasha Thoren	Chief Legal Officer	2025-08-25

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.

* This undertaking does not affect any limits Section 102(a) of the National Securities Markets Improvement Act of 1996 ("NSMIA") [Pub. L. No. 104-290, 110 Stat. 3416 (Oct. 11, 1996)] imposes on the ability of States to require information. As a result, if the securities that are the subject of this Form D are "covered securities" for purposes of NSMIA, whether in all instances or due to the nature of the offering that is the subject of this Form D, States cannot routinely require offering materials under this undertaking or otherwise and can require offering materials only to the extent NSMIA permits them to do so under NSMIA's preservation of their anti-fraud authority.

FAQ

What amount did X4 Pharmaceuticals (XFOR) raise in this Form D filing?

The filing reports a total offering amount of $84,999,985, with the total amount sold listed as $84,999,985 and $0 remaining.

Under which exemption was X4 Pharmaceuticals' offering conducted?

The offering was conducted under Rule 506(b) of Regulation D.

How many investors participated in X4 Pharmaceuticals' offering?

The Form D reports a total of 18 investors who have invested in the offering.

Were any proceeds used to pay executives, directors, or promoters?

The filing discloses $0 of the gross proceeds used for payments to named executive officers, directors, or promoters (estimated).

What sales commissions were paid in connection with the offering?

Sales commissions are disclosed as an estimated $3,300,000; finders' fees are listed as $0.

When did the first sale for this offering occur?

The Form D lists the date of first sale as 2025-08-13.