| Item 1. | |
| (a) | Name of issuer:
X4 Pharmaceuticals, Inc. |
| (b) | Address of issuer's principal executive offices:
61 North Beacon Street, 4th Floor, Boston, Massachusetts 02134 |
| Item 2. | |
| (a) | Name of person filing:
This report on Schedule 13G is being filed by Trails Edge Capital Partners, LP, a Delaware limited partnership ("Trails Edge Capital"). Trails Edge Capital is the investment manager to Trails Edge Biotechnology Master Fund, LP, a Cayman Islands limited partnership ("Trails Edge Biotechnology") and Ortav Yehudai ("Mr. Yehudai"), the Chief Investment Officer of Trails Edge Capital. Each of Trails Edge Capital, Trails Edge Biotechnology and Mr. Yehudai are referred to individually as a "Filer" and collectively as the "Filers". |
| (b) | Address or principal business office or, if none, residence:
The address for each Filer is 3455 Peachtree Road NE, 5th Floor, Atlanta, GA 30326. |
| (c) | Citizenship:
See Item 4 of the cover page of each Filer. |
| (d) | Title of class of securities:
Common Stock, par value $0.001 per share |
| (e) | CUSIP No.:
98420X202 |
| Item 3. | If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a: |
| (a) |  Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
|
| (b) | Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
|
| (c) | Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
|
| (d) | Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
|
| (e) | An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
|
| (f) | An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
|
| (g) | A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
|
| (h) | A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
|
| (i) | A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
|
| (j) | A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J),
please specify the type of institution:
|
| (k) | Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
|
| | |
| Item 4. | Ownership |
| (a) | Amount beneficially owned:
As of August 11, 2025, each Filer may be deemed to beneficially own an aggregate of 2,317,153 shares of common stock (the "Common Stock"), par value $0.001 (the "Shares"), of X4 Pharmaceuticals, Inc. (the "Issuer"). The 2,317,153 Shares reported as beneficially owned on this Schedule 13G by each Filer consists of the following: (i) 1,571,478 Shares held directly by Trails Edge Biotechnology, and (ii) 745,675 Shares underlying prefunded warrants (the "Warrants") held directly by Trails Edge Biotechnology. The securities beneficially owned by each Filer excludes 1,910,069 Shares underlying Warrants which contain an issuance limitation that prohibits the holder from exercising the Warrants to the extent that after giving effect to such issuance after the exercise, the holder (together with the holder's affiliates and any other persons acting as a group together with the holder or any of the holder's affiliates, including the other Filers) would beneficially own in excess of 9.99% of the Shares outstanding immediately after giving effect to the issuance of the Shares issuable upon exercise of the Warrants. As a result, Trails Edge Biotechnology beneficially owns 9.9% of the outstanding Shares of the Issuer as of August 11, 2025 (the "Event Date"). Trails Edge Capital, as the investment manager to Trails Edge Biotechnology, may be deemed to beneficially own these securities. Mr. Yehudai, as the Chief Investment Officer of Trails Edge Capital, exercises voting and investment discretion with respect to these securities and as such may be deemed to beneficially own 9.9% of the outstanding Shares of the Issuer as of the Event Date. Ownership percentages are based on (i) 11,408,357 shares of Common Stock issued and outstanding as of August 4, 2025, as reported by the Issuer in its Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2025, filed with the Securities and Exchange Commission on August 8, 2025, and (ii) 11,040,776 shares of Common Stock issued subsequent to August 4, 2025 as disclosed by the Issuer. |
| (b) | Percent of class:
9.9% |
| (c) | Number of shares as to which the person has:
|
| | (i) Sole power to vote or to direct the vote:
2,317,153
|
| | (ii) Shared power to vote or to direct the vote:
0
|
| | (iii) Sole power to dispose or to direct the disposition of:
2,317,153
|
| | (iv) Shared power to dispose or to direct the disposition of:
0
|
| Item 5. | Ownership of 5 Percent or Less of a Class. |
| | |
| Item 6. | Ownership of more than 5 Percent on Behalf of Another Person. |
| |
Not Applicable
|
| Item 7. | Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person. |
| |
Not Applicable
|
| Item 8. | Identification and Classification of Members of the Group. |
| |
Not Applicable
|
| Item 9. | Notice of Dissolution of Group. |
| |
Not Applicable
|
Rule 13d-1(c)