Welcome to our dedicated page for X4 Pharmaceuticals SEC filings (Ticker: XFOR), a comprehensive resource for investors and traders seeking official regulatory documents including 10-K annual reports, 10-Q quarterly earnings, 8-K material events, and insider trading forms.
X4 Pharmaceuticals, Inc. filings document a rare-disease biopharmaceutical issuer with commercial activity for XOLREMDI and development work around mavorixafor. Its 8-K reports cover operating and financial results, material agreements, restructuring actions, executive and board changes, and capital-structure updates involving common stock, pre-funded warrants, registration rights, and equity purchase arrangements.
Proxy materials describe shareholder voting matters, board composition, committee assignments, executive compensation, equity awards, and governance procedures. The filing record also includes disclosures tied to the company’s inducement and equity incentive practices, financing arrangements, and formal reporting of material corporate events.
X4 Pharmaceuticals outlines a major transition in its annual report for the year ended December 31, 2025. The company focuses on rare hematology diseases, led by XOLREMDI (mavorixafor), which has accelerated FDA approval for WHIM syndrome and Fast Track status in chronic neutropenia.
X4 is running the pivotal 52‑week Phase 3 4WARD trial in chronic neutropenia, targeting 176 patients and aiming for top-line data in the second half of 2027. In August 2025, the company overhauled leadership and executed restructurings that cut headcount by about 65% to align around this program.
Funding was strengthened through an August 2025 PIPE that raised net $81.0 million and a fourth-quarter public offering with net proceeds of $145.6 million, leaving $253.0 million in cash, cash equivalents and marketable securities as of December 31, 2025. X4 also signed regional commercialization deals, including a €28.5 million upfront license with Norgine and distribution agreements in Europe, MENA, and China, while a positive EMA opinion for WHIM is under review by the European Commission.
X4 Pharmaceuticals, Inc. ownership update: Morgan Stanley, Morgan Stanley Investment Management Inc., and Inception Trust report substantial beneficial ownership of Common Stock.
The filing shows Morgan Stanley reporting units hold 8,884,338 shares with shared voting and dispositive power (reported 10.2% of the class). Morgan Stanley Investment Management Inc. is reported with 8,884,304 shares (10.2%) and Inception Trust with 4,518,236 shares (5.2%). Signatories include authorized representatives for the three filers, dated 03/06/2026.
X4 Pharmaceuticals, Inc. received an amended Schedule 13G/A from Biotechnology Value Fund–affiliated entities and Mark N. Lampert reporting a significant but sub‑5% passive stake. As of December 31, 2025, the group may be deemed to beneficially own 3,411,993 common shares, or about 3.9% of the company.
The position includes Pre-Funded Common Stock Purchase Warrants exercisable for 1,178,251 shares, with a token exercise price of $0.001 per share and no expiry, subject to a 9.99% ownership cap. The filers certify the securities are not held to change or influence control of X4 Pharmaceuticals.
Trails Edge Capital Partners, Trails Edge Biotechnology Master Fund, and Ortav Yehudai report beneficial ownership of 5,227,222 shares of X4 Pharmaceuticals common stock as of December 31, 2025, representing 5.8% of the company.
The position includes 2,571,478 shares held directly and 2,655,744 shares underlying prefunded warrants, all held through Trails Edge Biotechnology. The ownership percentage is based on 87,436,688 shares outstanding as of October 31, 2025. The filers certify the holdings are not for the purpose of changing or influencing control of X4 Pharmaceuticals.
X4 Pharmaceuticals, Inc. disclosed that a group of Bain Capital Life Sciences funds and related entities collectively reported beneficial ownership of 8.41% of its common stock as of December 31, 2025. This total includes 615,649 common shares, a pre-funded warrant for up to 7,047,216 shares, and additional warrants for up to 304,589 shares.
The warrants and pre-funded warrants are subject to Beneficial Ownership Blockers that prevent exercises if the group would exceed 9.99% ownership of common stock, or 4.99% in the case of the Class C warrants, immediately after exercise.
Saturn V Capital Management LP and Xiaoying Tian report beneficial ownership of 6,433,481 shares of X4 Pharmaceuticals, Inc. common stock, representing 7.36% of the class. The percentage is based on 87,436,688 shares outstanding as of October 31, 2025.
The shares are held across pooled investment vehicles and managed accounts (the “Clients”) for which Saturn V serves as investment manager. Saturn V and Ms. Tian have shared voting and dispositive power over all 6,433,481 shares, with no sole voting or dispositive power.
No individual Client holds or beneficially owns five percent or more of X4’s outstanding shares, and both Saturn V and Ms. Tian expressly disclaim beneficial ownership of the shares held by the Clients. The filing certifies that the securities were acquired and are held in the ordinary course of business and not for the purpose of changing or influencing control of X4 Pharmaceuticals.
X4 Pharmaceuticals received an updated ownership report from Nantahala Capital Management and its principals. As of December 31, 2025, the reporting group may be deemed to beneficially own 2,449,468 shares of common stock, representing 2.80% of the outstanding shares.
The filing shows that Nantahala, Wilmot B. Harkey, and Daniel Mack share voting and dispositive power over these shares through funds and separately managed accounts. They certify the holdings are kept in the ordinary course of business and are not intended to change or influence control of X4 Pharmaceuticals.
Morgan Stanley and its investment management arm have reported a significant passive stake in X4 Pharmaceuticals, Inc. They beneficially own 8,196,489 shares of X4 common stock, representing 9.4% of the outstanding class as of December 31, 2025.
The filing shows no sole voting or dispositive power; all 8,196,489 shares are held with shared voting and shared dispositive power. The firms certify the holdings are in the ordinary course of business and not for the purpose of changing or influencing control of X4 Pharmaceuticals.
FMR LLC and Abigail P. Johnson report a significant passive ownership stake in X4 Pharmaceuticals, Inc. common stock on an amended Schedule 13G. They beneficially own 8,499,100 shares, representing 9.7% of the outstanding common stock, with sole dispositive power over all reported shares.
The filing states the shares were acquired and are held in the ordinary course of business and not for the purpose of changing or influencing control of X4 Pharmaceuticals, or in connection with any control-related transaction.
Empery Asset Management, LP and Ryan M. Lane report a significant stake in X4 Pharmaceuticals, Inc. They beneficially own 9,043,894 shares of X4 Pharmaceuticals common stock as of December 31, 2025, including 92,789 shares issuable upon exercise of warrants, representing 9.99% of the outstanding common stock.
This percentage is calculated using 90,436,688 shares outstanding, which includes 87,436,688 shares reported as of October 31, 2025 plus 3,000,000 shares issued from warrant exercises completed by December 31, 2025. The warrants are subject to a 9.99% “Blocker” that prevents the reporting persons from exercising warrants if it would push their ownership above 9.99% of the company’s outstanding common stock.
Empery Asset Management acts as investment manager to the funds that hold the shares and warrants, and Lane is the individual who ultimately oversees the investment manager. They certify that the holdings are in the ordinary course of business and not for the purpose of changing or influencing control of X4 Pharmaceuticals.