X4 Pharmaceuticals, Inc SEC filings XFOR
X4 Pharmaceuticals, Inc has 818 filings in SEC EDGAR's recent list, going back to Sep 24, 2010. Its latest annual report, Form ARS, was filed on Mar 20, 2026 for the period ended Dec 31, 2025. The latest quarterly report (Form 10-Q) was filed on Nov 4, 2026, covering the quarter ended Sep 30, 2026. The most recent current report (Form 8-K) was filed on Oct 29, 2026 (other events). The company's fiscal year ends on December 31.
| Form | Description | Filed | Period |
|---|---|---|---|
| 4 | Insider transaction | Oct 19, 2026 | Oct 16, 2026 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Oct 7, 2026 | — |
| 4 | Insider transaction | Oct 5, 2026 | Oct 1, 2026 |
| 144 | Notice of proposed sale | Oct 1, 2026 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Sep 21, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Aug 14, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Aug 14, 2026 | — |
| 4 | Insider transaction | Aug 13, 2026 | Aug 12, 2026 |
| 4 | Insider transaction | Aug 13, 2026 | Aug 12, 2026 |
| 144 | Notice of proposed sale | Aug 13, 2026 | — |
| 144 | Notice of proposed sale | Aug 13, 2026 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Jul 30, 2026 | — |
| 4 | Insider transaction | Jul 1, 2026 | Jun 30, 2026 |
| 4 | Insider transaction | Jul 1, 2026 | Jul 1, 2026 |
| 3 | Initial insider ownership | Jul 1, 2026 | Jul 1, 2026 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | May 15, 2026 | — |
| 4 | Insider transaction | May 13, 2026 | May 12, 2026 |
| 144 | Notice of proposed sale | May 12, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Mar 6, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Feb 17, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Feb 17, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Feb 17, 2026 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Feb 17, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Feb 13, 2026 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Feb 12, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Feb 5, 2026 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Jan 15, 2026 | — |
| 4 | Insider transaction | Jan 7, 2026 | Jan 1, 2026 |
| 4 | Insider transaction | Jan 5, 2026 | Jan 1, 2026 |
| 4 | Insider transaction | Jan 5, 2026 | Jan 1, 2026 |
| 4 | Insider transaction | Jan 5, 2026 | Jan 1, 2026 |
| SCHEDULE 13G | Ownership over 5% (passive) | Nov 14, 2025 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Nov 7, 2025 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Nov 3, 2025 | — |
| 4 | Insider transaction | Oct 31, 2025 | Oct 29, 2025 |
| 4 | Insider transaction | Oct 31, 2025 | Oct 29, 2025 |
| 4 | Insider transaction | Oct 31, 2025 | Oct 29, 2025 |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Oct 29, 2025 | — |
| 4 | Insider transaction | Oct 27, 2025 | Oct 23, 2025 |
| SCHEDULE 13G | Ownership over 5% (passive) | Oct 21, 2025 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Oct 3, 2025 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Sep 15, 2025 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Aug 20, 2025 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Aug 19, 2025 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Aug 18, 2025 | — |
| SCHEDULE 13D | Ownership over 5% (active) | Aug 18, 2025 | — |
| SCHEDULE 13D/A | Amended ownership over 5% (active) | Aug 15, 2025 | — |
| 4 | Insider transaction | Aug 14, 2025 | Aug 12, 2025 |
| 3 | Initial insider ownership | Aug 14, 2025 | Aug 12, 2025 |
| 3 | Initial insider ownership | Aug 14, 2025 | Aug 12, 2025 |
| 4 | Insider transaction | Aug 14, 2025 | Aug 12, 2025 |
| 4 | Insider transaction | Aug 14, 2025 | Aug 12, 2025 |
| 3 | Initial insider ownership | Aug 14, 2025 | Aug 12, 2025 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Aug 14, 2025 | — |
| SCHEDULE 13D | Ownership over 5% (active) | Aug 13, 2025 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Jul 18, 2025 | — |
| 4 | Insider transaction | Jul 3, 2025 | May 20, 2025 |
| 4 | Insider transaction | Jun 10, 2025 | Jun 9, 2025 |
| 4 | Insider transaction | Jun 10, 2025 | Jun 9, 2025 |
| 4 | Insider transaction | Jun 10, 2025 | Jun 9, 2025 |
| 4 | Insider transaction | Jun 10, 2025 | Jun 9, 2025 |
| 4 | Insider transaction | Jun 10, 2025 | Jun 9, 2025 |
| 4 | Insider transaction | Jun 10, 2025 | Jun 9, 2025 |
| 3 | Initial insider ownership | Jun 3, 2025 | May 20, 2025 |
| 4/A | Form 4/a | Jun 3, 2025 | May 16, 2025 |
| 4 | Insider transaction | May 20, 2025 | May 16, 2025 |
| 4 | Insider transaction | Feb 14, 2025 | Feb 12, 2025 |
| 4 | Insider transaction | Feb 14, 2025 | Feb 12, 2025 |
| 4 | Insider transaction | Feb 14, 2025 | Feb 12, 2025 |
| 4 | Insider transaction | Feb 14, 2025 | May 17, 2024 |
| 4 | Insider transaction | Feb 14, 2025 | Feb 12, 2025 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Jan 31, 2025 | — |
| 4 | Insider transaction | Jan 27, 2025 | Jan 23, 2025 |
| 4 | Insider transaction | Jan 27, 2025 | Jan 23, 2025 |
| 4 | Insider transaction | Jan 27, 2025 | Jan 23, 2025 |
| 4 | Insider transaction | Jan 27, 2025 | Jan 23, 2025 |
| 4 | Insider transaction | Jan 27, 2025 | Jan 23, 2025 |
| 144 | Notice of proposed sale | Jan 24, 2025 | — |
| 144 | Notice of proposed sale | Jan 24, 2025 | — |
| 144 | Notice of proposed sale | Jan 24, 2025 | — |
| 144 | Notice of proposed sale | Jan 24, 2025 | — |
| 144 | Notice of proposed sale | Jan 24, 2025 | — |
| 144 | Notice of proposed sale | Jan 24, 2025 | — |
| 4 | Insider transaction | Nov 19, 2024 | Nov 15, 2024 |
| 144 | Notice of proposed sale | Nov 15, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Nov 12, 2024 | — |
| SC 13G | Ownership over 5% (passive) | Nov 8, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Nov 4, 2024 | — |
| SC 13G | Ownership over 5% (passive) | Oct 22, 2024 | — |
| 4 | Insider transaction | Oct 16, 2024 | Oct 15, 2024 |
| 144 | Notice of proposed sale | Oct 15, 2024 | — |
| 4 | Insider transaction | Oct 8, 2024 | Oct 4, 2024 |
| 4 | Insider transaction | Oct 8, 2024 | Oct 4, 2024 |
| 4 | Insider transaction | Oct 8, 2024 | Oct 4, 2024 |
| 4 | Insider transaction | Oct 8, 2024 | Oct 4, 2024 |
| 4 | Insider transaction | Oct 8, 2024 | Oct 4, 2024 |
| 144 | Notice of proposed sale | Oct 7, 2024 | — |
| 144 | Notice of proposed sale | Oct 7, 2024 | — |
| 144 | Notice of proposed sale | Oct 7, 2024 | — |
| 144 | Notice of proposed sale | Oct 7, 2024 | — |
| 144 | Notice of proposed sale | Oct 7, 2024 | — |
| 4 | Insider transaction | Sep 11, 2024 | Sep 9, 2024 |
| 144 | Notice of proposed sale | Sep 9, 2024 | — |
| 4 | Insider transaction | Jun 11, 2024 | Jun 10, 2024 |
| 4 | Insider transaction | Jun 11, 2024 | Jun 10, 2024 |
| 4 | Insider transaction | Jun 11, 2024 | Jun 10, 2024 |
| 4 | Insider transaction | Jun 11, 2024 | Jun 10, 2024 |
| 4 | Insider transaction | Jun 11, 2024 | Jun 10, 2024 |
| 4 | Insider transaction | Jun 11, 2024 | Jun 10, 2024 |
| 4 | Insider transaction | Jun 11, 2024 | Jun 10, 2024 |
| 4 | Insider transaction | Jun 11, 2024 | Jun 10, 2024 |
| 4 | Insider transaction | Mar 11, 2024 | Mar 11, 2024 |
| 4 | Insider transaction | Mar 11, 2024 | Mar 11, 2024 |
| 4 | Insider transaction | Mar 11, 2024 | Mar 11, 2024 |
| 4 | Insider transaction | Mar 11, 2024 | Mar 11, 2024 |
| 144 | Notice of proposed sale | Mar 11, 2024 | — |
| 144 | Notice of proposed sale | Mar 11, 2024 | — |
| 144 | Notice of proposed sale | Mar 11, 2024 | — |
| 144 | Notice of proposed sale | Mar 11, 2024 | — |
| 4/A | Form 4/a | Feb 28, 2024 | Feb 13, 2024 |
| 4 | Insider transaction | Feb 16, 2024 | Feb 13, 2024 |
| 4 | Insider transaction | Feb 16, 2024 | Feb 13, 2024 |
| 4 | Insider transaction | Feb 16, 2024 | Feb 13, 2024 |
| 4 | Insider transaction | Feb 16, 2024 | Feb 13, 2024 |
| 4 | Insider transaction | Feb 16, 2024 | Feb 13, 2024 |
| 4 | Insider transaction | Feb 16, 2024 | Feb 13, 2024 |
| SC 13G/A | Amended ownership over 5% (passive) | Feb 14, 2024 | — |
| SC 13G | Ownership over 5% (passive) | Feb 14, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Feb 14, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Feb 13, 2024 | — |
| 4 | Insider transaction | Feb 12, 2024 | Feb 12, 2024 |
| 4 | Insider transaction | Feb 12, 2024 | Feb 12, 2024 |
| 4 | Insider transaction | Feb 12, 2024 | Feb 12, 2024 |
| 4 | Insider transaction | Feb 12, 2024 | Feb 12, 2024 |
| 144 | Notice of proposed sale | Feb 12, 2024 | — |
| 144 | Notice of proposed sale | Feb 12, 2024 | — |
| 144 | Notice of proposed sale | Feb 12, 2024 | — |
| 144 | Notice of proposed sale | Feb 12, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Feb 7, 2024 | — |
| SC 13G | Ownership over 5% (passive) | Jan 31, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Jan 16, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Jan 8, 2024 | — |
| 4 | Insider transaction | Nov 3, 2023 | Nov 1, 2023 |
| 4 | Insider transaction | Nov 3, 2023 | Nov 1, 2023 |
| 4 | Insider transaction | Nov 3, 2023 | Nov 1, 2023 |
| 4 | Insider transaction | Nov 3, 2023 | Nov 1, 2023 |
| 4 | Insider transaction | Nov 3, 2023 | Nov 1, 2023 |
| 144 | Notice of proposed sale | Nov 3, 2023 | — |
| 4 | Insider transaction | Nov 2, 2023 | Oct 31, 2023 |
| 4 | Insider transaction | Nov 2, 2023 | Oct 31, 2023 |
| 4 | Insider transaction | Nov 2, 2023 | Oct 31, 2023 |
| 4 | Insider transaction | Nov 2, 2023 | Oct 31, 2023 |
| 4 | Insider transaction | Nov 2, 2023 | Oct 31, 2023 |
| 144 | Notice of proposed sale | Nov 1, 2023 | — |
| 144 | Notice of proposed sale | Nov 1, 2023 | — |
| 144 | Notice of proposed sale | Nov 1, 2023 | — |
| 144 | Notice of proposed sale | Nov 1, 2023 | — |
| 144 | Notice of proposed sale | Nov 1, 2023 | — |
| 4 | Insider transaction | Oct 18, 2023 | Oct 16, 2023 |
| 3 | Initial insider ownership | Oct 18, 2023 | Oct 16, 2023 |
| 4 | Insider transaction | Sep 12, 2023 | Sep 8, 2023 |
| 144 | Notice of proposed sale | Sep 8, 2023 | — |
| 4 | Insider transaction | Sep 5, 2023 | Aug 31, 2023 |
| 4 | Insider transaction | Aug 22, 2023 | Aug 18, 2023 |
| 3 | Initial insider ownership | Aug 16, 2023 | Aug 16, 2023 |
| 4 | Insider transaction | Aug 11, 2023 | Aug 9, 2023 |
| 4 | Insider transaction | Jul 5, 2023 | Jun 30, 2023 |
| 4 | Insider transaction | Jul 5, 2023 | Jun 30, 2023 |
| 144 | Notice of proposed sale | Jun 30, 2023 | — |
| 144 | Notice of proposed sale | Jun 30, 2023 | — |
| 4 | Insider transaction | Jun 26, 2023 | Jun 23, 2023 |
| 4 | Insider transaction | Jun 26, 2023 | Jun 23, 2023 |
| 4 | Insider transaction | Jun 26, 2023 | Jun 23, 2023 |
| 144 | Notice of proposed sale | Jun 23, 2023 | — |
| 144 | Notice of proposed sale | Jun 23, 2023 | — |
| 144 | Notice of proposed sale | Jun 23, 2023 | — |
| 4 | Insider transaction | Jun 16, 2023 | Jun 15, 2023 |
| 4 | Insider transaction | Jun 16, 2023 | Jun 15, 2023 |
| 4 | Insider transaction | Jun 16, 2023 | Jun 15, 2023 |
| SC 13G | Ownership over 5% (passive) | Jun 16, 2023 | — |
| 144 | Notice of proposed sale | Jun 15, 2023 | — |
| 144 | Notice of proposed sale | Jun 15, 2023 | — |
| 144 | Notice of proposed sale | Jun 15, 2023 | — |
| 4 | Insider transaction | Jun 14, 2023 | Jun 13, 2023 |
| 4 | Insider transaction | Jun 14, 2023 | Jun 13, 2023 |
| 4 | Insider transaction | Jun 14, 2023 | Jun 13, 2023 |
| 4 | Insider transaction | Jun 14, 2023 | Jun 13, 2023 |
| 4 | Insider transaction | Jun 14, 2023 | Jun 13, 2023 |
| 4 | Insider transaction | Jun 14, 2023 | Jun 13, 2023 |
| 4 | Insider transaction | May 31, 2023 | May 31, 2023 |
| 144 | Notice of proposed sale | May 31, 2023 | — |
| SC 13D/A | Amended ownership over 5% (active) | May 26, 2023 | — |
| 4 | Insider transaction | Mar 13, 2023 | Mar 10, 2023 |
| 4 | Insider transaction | Mar 13, 2023 | Mar 10, 2023 |
| 4 | Insider transaction | Mar 13, 2023 | Mar 10, 2023 |
| 4 | Insider transaction | Mar 13, 2023 | Mar 10, 2023 |
| 4 | Insider transaction | Feb 15, 2023 | Feb 13, 2023 |
| 4 | Insider transaction | Feb 15, 2023 | Feb 13, 2023 |
| 4 | Insider transaction | Feb 15, 2023 | Feb 13, 2023 |
| 4 | Insider transaction | Feb 15, 2023 | Feb 13, 2023 |
Showing 200 filings, the most recent 200. Main filings leave out insider and ownership forms such as Form 4; choose a type above to see them. Each form opens on SEC.gov. Older filings are on SEC EDGAR.
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Company profile
- Industry
- Biological Products, (No Diagnostic Substances) (SIC 2836)
- Listed as
- XFOR (Nasdaq)
- Fiscal year ends
- December 31
- Incorporated in
- DE
- Headquarters
- Boston, MA
- SEC filer status
- Non-accelerated filer, Smaller reporting company
- SEC CIK
- 1501697
- Former names
- Arsanis, Inc. (until Mar 13, 2019)
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All 182 Biological Products, (No Diagnostic Substances) companies
Source: SEC EDGAR filings. This is company-reported data, not investment advice.