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 |
|---|---|---|---|
| 10-Q | Quarterly report | Nov 4, 2026 | Sep 30, 2026 |
| 8-K |
Current report
Other events
|
Oct 29, 2026 | Oct 29, 2026 |
| 4 | Insider transaction | Oct 19, 2026 | Oct 16, 2026 |
| 8-K |
Current report
Material agreement, Agreement ended, New debt, Unregistered share sale, Regulation FD disclosure
|
Oct 8, 2026 | Oct 7, 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 | — |
| 8-K |
Current report
Other events
|
Sep 9, 2026 | Sep 8, 2026 |
| 8-K |
Current report
Other events
|
Sep 8, 2026 | Sep 8, 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 | — |
| 10-Q | Quarterly report | Aug 6, 2026 | Jun 30, 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 |
| 8-K |
Current report
Officer or director change, Regulation FD disclosure
|
Jul 1, 2026 | Jun 30, 2026 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | May 15, 2026 | — |
| EFFECT | Filing | May 14, 2026 | — |
| 8-K/A |
Amended current report
Officer or director change, Shareholder vote results
|
May 13, 2026 | May 11, 2026 |
| 4 | Insider transaction | May 13, 2026 | May 12, 2026 |
| 144 | Notice of proposed sale | May 12, 2026 | — |
| 8-K |
Current report
Officer or director change, Shareholder vote results
|
May 12, 2026 | May 11, 2026 |
| CORRESP | Letter to the SEC | May 12, 2026 | — |
| UPLOAD | Letter from the SEC | May 11, 2026 | — |
| S-3 | Shelf registration | May 6, 2026 | — |
| 10-Q | Quarterly report | May 6, 2026 | Mar 31, 2026 |
| ARS | Annual report to shareholders | Mar 20, 2026 | Dec 31, 2025 |
| DEFA14A | Additional proxy material | Mar 20, 2026 | — |
| DEF 14A | Proxy statement | Mar 20, 2026 | Mar 20, 2026 |
| S-8 | Employee stock plan registration | Mar 18, 2026 | — |
| 10-K | Annual report | Mar 17, 2026 | Dec 31, 2025 |
| 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 | — |
| 10-Q | Quarterly report | Nov 5, 2025 | Sep 30, 2025 |
| 8-K |
Current report
Results of operations
|
Nov 5, 2025 | Nov 5, 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 |
| 8-K |
Current report
Material agreement
|
Oct 27, 2025 | Oct 23, 2025 |
| 424B5 | Prospectus supplement | Oct 24, 2025 | — |
| 424B5 | Prospectus supplement | Oct 23, 2025 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Oct 21, 2025 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Oct 3, 2025 | — |
| 424B3 | Prospectus | Sep 18, 2025 | — |
| EFFECT | Filing | Sep 17, 2025 | — |
| 8-K |
Current report
Exit or restructuring costs, Officer or director change, Regulation FD disclosure
|
Sep 17, 2025 | Sep 15, 2025 |
| CORRESP | Letter to the SEC | Sep 15, 2025 | — |
| SCHEDULE 13G | Ownership over 5% (passive) | Sep 15, 2025 | — |
| UPLOAD | Letter from the SEC | Sep 15, 2025 | — |
| S-3 | Shelf registration | Sep 10, 2025 | — |
| S-8 | Employee stock plan registration | Sep 10, 2025 | — |
| D | Filing | Aug 25, 2025 | — |
| 8-K |
Current report
Officer or director change
|
Aug 25, 2025 | Aug 22, 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 | — |
| 8-K |
Current report
Material agreement, Unregistered share sale, Other events
|
Aug 13, 2025 | Aug 12, 2025 |
| 8-K |
Current report
Material agreement, Unregistered share sale, Officer or director change, Other events
|
Aug 12, 2025 | Aug 11, 2025 |
| 10-Q | Quarterly report | Aug 8, 2025 | Jun 30, 2025 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Jul 18, 2025 | — |
| 4 | Insider transaction | Jul 3, 2025 | May 20, 2025 |
| 8-K |
Current report
Material agreement
|
Jun 23, 2025 | Jun 23, 2025 |
| 424B5 | Prospectus supplement | Jun 23, 2025 | — |
| 8-K |
Current report
Shareholder vote results
|
Jun 11, 2025 | Jun 11, 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 |
| 10-Q | Quarterly report | May 1, 2025 | Mar 31, 2025 |
| 8-K |
Current report
Results of operations, Regulation FD disclosure
|
May 1, 2025 | May 1, 2025 |
| DEF 14A | Proxy statement | Apr 25, 2025 | Apr 25, 2025 |
| DEFA14A | Additional proxy material | Apr 25, 2025 | — |
| 8-K |
Current report
Bylaw or fiscal year change, Other events
|
Apr 24, 2025 | Apr 24, 2025 |
| 8-K |
Current report
Shareholder vote results
|
Apr 18, 2025 | Apr 17, 2025 |
| S-8 | Employee stock plan registration | Mar 26, 2025 | — |
| 10-K | Annual report | Mar 26, 2025 | Dec 31, 2024 |
| 8-K |
Current report
Results of operations
|
Mar 25, 2025 | Mar 25, 2025 |
| DEF 14A | Proxy statement | Mar 24, 2025 | Mar 24, 2025 |
| PRE 14A | Preliminary proxy statement | Mar 14, 2025 | Mar 14, 2025 |
| 8-K |
Current report
Other events
|
Mar 3, 2025 | Mar 3, 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 |
| 8-K |
Current report
Exit or restructuring costs, Regulation FD disclosure
|
Feb 6, 2025 | Feb 6, 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 | — |
| S-8 | Employee stock plan registration | Jan 16, 2025 | — |
| 8-K |
Current report
Material agreement, Regulation FD disclosure
|
Jan 13, 2025 | Jan 13, 2025 |
| UPLOAD | Letter from the SEC | Jan 7, 2025 | — |
| CORRESP | Letter to the SEC | Dec 23, 2024 | — |
| UPLOAD | Letter from the SEC | Dec 13, 2024 | — |
| 4 | Insider transaction | Nov 19, 2024 | Nov 15, 2024 |
| 144 | Notice of proposed sale | Nov 15, 2024 | — |
| 10-Q | Quarterly report | Nov 13, 2024 | Sep 30, 2024 |
| 8-K |
Current report
Regulation FD disclosure, Other events
|
Nov 13, 2024 | Nov 13, 2024 |
| 8-K |
Current report
Results of operations
|
Nov 13, 2024 | Nov 13, 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 | — |
| S-8 | Employee stock plan registration | Oct 4, 2024 | — |
| 4 | Insider transaction | Sep 11, 2024 | Sep 9, 2024 |
| 144 | Notice of proposed sale | Sep 9, 2024 | — |
| 8-K |
Current report
Listing notice
|
Aug 16, 2024 | Aug 13, 2024 |
| 8-K |
Current report
Regulation FD disclosure
|
Aug 9, 2024 | Aug 8, 2024 |
| 10-Q | Quarterly report | Aug 8, 2024 | Jun 30, 2024 |
| 8-K |
Current report
Results of operations
|
Aug 8, 2024 | Aug 8, 2024 |
| 8-K |
Current report
Regulation FD disclosure
|
Jul 19, 2024 | Jul 19, 2024 |
| 8-K |
Current report
Regulation FD disclosure, Other events
|
Jun 27, 2024 | Jun 27, 2024 |
| 8-K |
Current report
Shareholder vote results
|
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 | Jun 11, 2024 | Jun 10, 2024 |
| 8-K |
Current report
Regulation FD disclosure
|
May 22, 2024 | May 22, 2024 |
| 8-K |
Current report
Material agreement, Acquisition or sale of assets, Officer or director change, Regulation FD disclosure, Other events
|
May 9, 2024 | May 8, 2024 |
| 10-Q | Quarterly report | May 7, 2024 | Mar 31, 2024 |
| 8-K |
Current report
Results of operations
|
May 7, 2024 | May 7, 2024 |
| ARS | Annual report to shareholders | Apr 29, 2024 | Dec 31, 2023 |
| DEFA14A | Additional proxy material | Apr 29, 2024 | — |
| DEF 14A | Proxy statement | Apr 29, 2024 | Apr 29, 2024 |
| 8-K |
Current report
Regulation FD disclosure, Other events
|
Apr 29, 2024 | Apr 29, 2024 |
| 8-K |
Current report
Regulation FD disclosure, Other events
|
Apr 29, 2024 | Apr 29, 2024 |
| 8-K |
Current report
Other events
|
Apr 5, 2024 | Apr 5, 2024 |
| 8-K |
Current report
Regulation FD disclosure
|
Apr 1, 2024 | Apr 1, 2024 |
| 10-K | Annual report | Mar 21, 2024 | Dec 31, 2023 |
| 8-K |
Current report
Results of operations
|
Mar 21, 2024 | Mar 21, 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 | — |
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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.