| 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 4. | Ownership |
| (a) | Amount beneficially owned:
As of December 31, 2025 (the "Event Date"), each Filer may be deemed to beneficially own an aggregate of 5,227,222 shares of common stock (the "Common Stock"), par value $0.001 (the "Shares"), of X4 Pharmaceuticals, Inc. (the "Issuer"). The 5,227,222 Shares reported as beneficially owned on this Schedule 13G by each Filer consists of the following: (i) 2,571,478 Shares held directly by Trails Edge Biotechnology, and (ii) 2,655,744 Shares underlying prefunded warrants (the "Warrants") held directly by Trails Edge Biotechnology. As a result, Trails Edge Biotechnology beneficially owns 5.8% of the outstanding Shares of the Issuer as of 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 5.8% of the outstanding Shares of the Issuer as of the Event Date. Ownership percentages are based on 87,436,688 shares of Common Stock issued and outstanding as of October 31, 2025, as reported by the Issuer in its Quarterly Report on Form 10-Q for the quarterly period ended September 30, 2025, filed with the Securities and Exchange Commission on November 5, 2025. |
| (b) | Percent of class:
5.8% |
| (c) | Number of shares as to which the person has:
|
| | (i) Sole power to vote or to direct the vote:
5,227,222.00
|
| | (ii) Shared power to vote or to direct the vote:
0
|
| | (iii) Sole power to dispose or to direct the disposition of:
5,227,222.00
|
| | (iv) Shared power to dispose or to direct the disposition of:
0
|
| 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(b)
Rule 13d-1(c)