American Superconductor Corp /DE/ SEC filings AMSC
American Superconductor Corp /DE/ has 1,003 filings in SEC EDGAR's recent list, going back to Jan 31, 2008. Its latest annual report, Form ARS, was filed on Jun 18, 2026 for the period ended Mar 31, 2026. 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 Nov 4, 2026 (results of operations). The company's fiscal year ends on March 31.
| Form | Description | Filed | Period |
|---|---|---|---|
| 10-Q | Quarterly report | Nov 4, 2026 | Sep 30, 2026 |
| 8-K |
Current report
Results of operations
|
Nov 4, 2026 | Nov 4, 2026 |
| 4 | Insider transaction | Sep 21, 2026 | Sep 18, 2026 |
| 8-K |
Current report
Officer or director change
|
Sep 21, 2026 | Sep 17, 2026 |
| 10-Q | Quarterly report | Aug 5, 2026 | Jun 30, 2026 |
| 8-K |
Current report
Results of operations, Shareholder vote results
|
Aug 5, 2026 | Jul 31, 2026 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Jul 31, 2026 | — |
| ARS | Annual report to shareholders | Jun 18, 2026 | Mar 31, 2026 |
| DEFA14A | Additional proxy material | Jun 18, 2026 | — |
| DEF 14A | Proxy statement | Jun 18, 2026 | Jul 31, 2026 |
| 4 | Insider transaction | Jun 12, 2026 | Jun 11, 2026 |
| 144 | Notice of proposed sale | Jun 11, 2026 | — |
| 4 | Insider transaction | Jun 11, 2026 | Jun 11, 2026 |
| 4 | Insider transaction | Jun 11, 2026 | Jun 11, 2026 |
| 144 | Notice of proposed sale | Jun 11, 2026 | — |
| 4 | Insider transaction | Jun 10, 2026 | Jun 8, 2026 |
| 4 | Insider transaction | Jun 10, 2026 | Jun 8, 2026 |
| 144 | Notice of proposed sale | Jun 10, 2026 | — |
| 144 | Notice of proposed sale | Jun 8, 2026 | — |
| 144 | Notice of proposed sale | Jun 8, 2026 | — |
| 144 | Notice of proposed sale | Jun 3, 2026 | — |
| 144 | Notice of proposed sale | Jun 3, 2026 | — |
| 4 | Insider transaction | Jun 3, 2026 | Jun 1, 2026 |
| 4 | Insider transaction | Jun 3, 2026 | Jun 1, 2026 |
| 144 | Notice of proposed sale | Jun 2, 2026 | — |
| 144 | Notice of proposed sale | Jun 2, 2026 | — |
| 8-K |
Current report
Officer or director change
|
Jun 2, 2026 | Jun 1, 2026 |
| SD | Specialized disclosure (conflict minerals) | May 29, 2026 | — |
| 10-K | Annual report | May 27, 2026 | Mar 31, 2026 |
| 8-K |
Current report
Results of operations
|
May 27, 2026 | May 27, 2026 |
| SCHEDULE 13G | Ownership over 5% (passive) | Apr 29, 2026 | — |
| 4 | Insider transaction | Apr 7, 2026 | Apr 3, 2026 |
| 4 | Insider transaction | Apr 7, 2026 | Apr 3, 2026 |
| 4 | Insider transaction | Apr 7, 2026 | Apr 3, 2026 |
| 4 | Insider transaction | Apr 7, 2026 | Apr 3, 2026 |
| 4 | Insider transaction | Apr 7, 2026 | Apr 3, 2026 |
| 4 | Insider transaction | Apr 7, 2026 | Apr 3, 2026 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Mar 26, 2026 | — |
| 4 | Insider transaction | Feb 26, 2026 | Feb 24, 2026 |
| 8-K/A | Amended current report | Feb 17, 2026 | Dec 5, 2025 |
| 10-Q | Quarterly report | Feb 4, 2026 | Dec 31, 2025 |
| 8-K |
Current report
Results of operations
|
Feb 4, 2026 | Feb 4, 2026 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Jan 30, 2026 | — |
| 8-K |
Current report
Other events
|
Dec 23, 2025 | Dec 23, 2025 |
| 424B7 | Filing | Dec 23, 2025 | — |
| 8-K |
Current report
Material agreement, Acquisition or sale of assets, Unregistered share sale, Other events
|
Dec 10, 2025 | Dec 5, 2025 |
| 4 | Insider transaction | Nov 13, 2025 | Jun 18, 2019 |
| 10-Q | Quarterly report | Nov 5, 2025 | Sep 30, 2025 |
| 8-K |
Current report
Results of operations
|
Nov 5, 2025 | Nov 5, 2025 |
| 144 | Notice of proposed sale | Aug 8, 2025 | — |
| 4 | Insider transaction | Aug 8, 2025 | Aug 6, 2025 |
| 4 | Insider transaction | Aug 6, 2025 | Aug 4, 2022 |
| 4 | Insider transaction | Aug 6, 2025 | Aug 4, 2025 |
| 4 | Insider transaction | Aug 6, 2025 | Aug 4, 2025 |
| 144 | Notice of proposed sale | Aug 4, 2025 | — |
| 144 | Notice of proposed sale | Aug 4, 2025 | — |
| 10-Q | Quarterly report | Jul 30, 2025 | Jun 30, 2025 |
| 8-K |
Current report
Results of operations
|
Jul 30, 2025 | Jul 30, 2025 |
| 8-K |
Current report
Shareholder vote results
|
Jul 29, 2025 | Jul 25, 2025 |
| ARS | Annual report to shareholders | Jun 13, 2025 | Mar 31, 2025 |
| DEFA14A | Additional proxy material | Jun 13, 2025 | — |
| DEF 14A | Proxy statement | Jun 13, 2025 | Jul 25, 2025 |
| 4 | Insider transaction | Jun 12, 2025 | Jun 11, 2025 |
| 4 | Insider transaction | Jun 12, 2025 | Jun 11, 2025 |
| 8-K |
Current report
Other events
|
Jun 11, 2025 | Jun 10, 2025 |
| 424B5 | Prospectus supplement | Jun 11, 2025 | — |
| 144 | Notice of proposed sale | Jun 11, 2025 | — |
| 144 | Notice of proposed sale | Jun 11, 2025 | — |
| 424B5 | Prospectus supplement | Jun 10, 2025 | — |
| 4 | Insider transaction | Jun 9, 2025 | Jun 6, 2025 |
| 4 | Insider transaction | Jun 9, 2025 | Jun 6, 2025 |
| 144 | Notice of proposed sale | Jun 6, 2025 | — |
| 144 | Notice of proposed sale | Jun 6, 2025 | — |
| 4 | Insider transaction | May 29, 2025 | May 27, 2025 |
| 4 | Insider transaction | May 29, 2025 | May 27, 2025 |
| 4 | Insider transaction | May 29, 2025 | May 27, 2025 |
| 3 | Initial insider ownership | May 29, 2025 | May 27, 2025 |
| 144 | Notice of proposed sale | May 27, 2025 | — |
| 144 | Notice of proposed sale | May 27, 2025 | — |
| 4 | Insider transaction | May 22, 2025 | May 20, 2025 |
| 4 | Insider transaction | May 22, 2025 | May 20, 2025 |
| SD | Specialized disclosure (conflict minerals) | May 21, 2025 | — |
| 10-K | Annual report | May 21, 2025 | Mar 31, 2025 |
| 8-K |
Current report
Results of operations, Officer or director change
|
May 21, 2025 | May 15, 2025 |
| 144 | Notice of proposed sale | May 20, 2025 | — |
| 144 | Notice of proposed sale | May 20, 2025 | — |
| 4 | Insider transaction | May 19, 2025 | May 15, 2025 |
| 4 | Insider transaction | May 19, 2025 | May 15, 2025 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Apr 17, 2025 | — |
| 4 | Insider transaction | Apr 4, 2025 | Apr 3, 2025 |
| 4 | Insider transaction | Apr 4, 2025 | Apr 3, 2025 |
| 4 | Insider transaction | Apr 4, 2025 | Apr 3, 2025 |
| 4 | Insider transaction | Apr 4, 2025 | Apr 3, 2025 |
| 4 | Insider transaction | Apr 4, 2025 | Apr 3, 2025 |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Feb 12, 2025 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Feb 5, 2025 | — |
| 8-K |
Current report
Results of operations, Bylaw or fiscal year change
|
Feb 5, 2025 | Jan 30, 2025 |
| 10-Q | Quarterly report | Feb 5, 2025 | Dec 31, 2024 |
| SC 13G/A | Amended ownership over 5% (passive) | Nov 12, 2024 | — |
| SC 13G | Ownership over 5% (passive) | Nov 8, 2024 | — |
| 4 | Insider transaction | Nov 6, 2024 | Nov 4, 2024 |
| 144 | Notice of proposed sale | Nov 5, 2024 | — |
| SC 13G | Ownership over 5% (passive) | Nov 4, 2024 | — |
| SCHEDULE 13G/A | Amended ownership over 5% (passive) | Nov 4, 2024 | — |
| 10-Q | Quarterly report | Oct 30, 2024 | Sep 30, 2024 |
| 8-K |
Current report
Results of operations
|
Oct 30, 2024 | Oct 30, 2024 |
| SC 13G | Ownership over 5% (passive) | Oct 22, 2024 | — |
| 4 | Insider transaction | Oct 1, 2024 | Sep 30, 2024 |
| 4 | Insider transaction | Sep 30, 2024 | Sep 26, 2024 |
| S-8 | Employee stock plan registration | Aug 28, 2024 | — |
| 8-K |
Current report
Other events
|
Aug 13, 2024 | Aug 12, 2024 |
| 424B7 | Filing | Aug 12, 2024 | — |
| S-3ASR | Automatic shelf registration | Aug 12, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Aug 9, 2024 | — |
| 8-K/A | Amended current report | Aug 6, 2024 | Aug 1, 2024 |
| 10-Q | Quarterly report | Aug 6, 2024 | Jun 30, 2024 |
| 8-K |
Current report
Results of operations
|
Aug 6, 2024 | Aug 6, 2024 |
| 8-K |
Current report
Officer or director change, Shareholder vote results
|
Aug 5, 2024 | Aug 2, 2024 |
| 8-K |
Current report
Material agreement, Acquisition or sale of assets, Other events
|
Aug 5, 2024 | Aug 1, 2024 |
| ARS | Annual report to shareholders | Jun 20, 2024 | Mar 31, 2024 |
| DEFA14A | Additional proxy material | Jun 20, 2024 | — |
| DEF 14A | Proxy statement | Jun 20, 2024 | Aug 2, 2024 |
| 4 | Insider transaction | Jun 12, 2024 | Jun 11, 2024 |
| 4 | Insider transaction | Jun 12, 2024 | Jun 11, 2024 |
| 144 | Notice of proposed sale | Jun 11, 2024 | — |
| 144 | Notice of proposed sale | Jun 11, 2024 | — |
| PRE 14A | Preliminary proxy statement | Jun 10, 2024 | Aug 2, 2024 |
| 10-K | Annual report | May 29, 2024 | Mar 31, 2024 |
| 8-K |
Current report
Results of operations, Officer or director change
|
May 29, 2024 | May 23, 2024 |
| SD | Specialized disclosure (conflict minerals) | May 28, 2024 | — |
| 4 | Insider transaction | May 23, 2024 | May 21, 2024 |
| 4 | Insider transaction | May 23, 2024 | May 21, 2024 |
| 144 | Notice of proposed sale | May 21, 2024 | — |
| 144 | Notice of proposed sale | May 21, 2024 | — |
| 4 | Insider transaction | Apr 4, 2024 | Apr 3, 2024 |
| 4 | Insider transaction | Apr 4, 2024 | Apr 3, 2024 |
| 4 | Insider transaction | Apr 4, 2024 | Apr 3, 2024 |
| 4 | Insider transaction | Apr 4, 2024 | Apr 3, 2024 |
| 4 | Insider transaction | Apr 4, 2024 | Apr 3, 2024 |
| EFFECT | Filing | Mar 15, 2024 | — |
| CORRESP | Letter to the SEC | Mar 13, 2024 | — |
| S-3/A | Filing | Mar 8, 2024 | — |
| CORRESP | Letter to the SEC | Mar 6, 2024 | — |
| CORRESP | Letter to the SEC | Mar 5, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Feb 14, 2024 | — |
| UPLOAD | Letter from the SEC | Feb 5, 2024 | — |
| 424B5 | Prospectus supplement | Jan 31, 2024 | — |
| 8-K |
Current report
Other events
|
Jan 31, 2024 | Jan 30, 2024 |
| 424B5 | Prospectus supplement | Jan 30, 2024 | — |
| S-3 | Shelf registration | Jan 30, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Jan 30, 2024 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Jan 30, 2024 | — |
| 10-Q | Quarterly report | Jan 24, 2024 | Dec 31, 2023 |
| 8-K |
Current report
Results of operations
|
Jan 24, 2024 | Jan 24, 2024 |
| 10-Q | Quarterly report | Nov 1, 2023 | Sep 30, 2023 |
| 8-K |
Current report
Results of operations
|
Nov 1, 2023 | Nov 1, 2023 |
| 8-K |
Current report
Shareholder vote results
|
Aug 11, 2023 | Aug 11, 2023 |
| 10-Q | Quarterly report | Aug 9, 2023 | Jun 30, 2023 |
| 8-K |
Current report
Results of operations
|
Aug 9, 2023 | Aug 9, 2023 |
| SC 13G/A | Amended ownership over 5% (passive) | Jul 5, 2023 | — |
| ARS | Annual report to shareholders | Jun 28, 2023 | Dec 31, 2022 |
| DEFA14A | Additional proxy material | Jun 28, 2023 | — |
| DEF 14A | Proxy statement | Jun 28, 2023 | Aug 11, 2023 |
| 4 | Insider transaction | Jun 23, 2023 | Jun 21, 2023 |
| 4 | Insider transaction | Jun 23, 2023 | Jun 21, 2023 |
| 144 | Notice of proposed sale | Jun 22, 2023 | — |
| 144 | Notice of proposed sale | Jun 22, 2023 | — |
| 144 | Notice of proposed sale | Jun 21, 2023 | — |
| 144 | Notice of proposed sale | Jun 21, 2023 | — |
| 8-K |
Current report
Officer or director change
|
Jun 21, 2023 | Jun 15, 2023 |
| 4 | Insider transaction | Jun 20, 2023 | Jun 15, 2023 |
| 4 | Insider transaction | Jun 20, 2023 | Jun 15, 2023 |
| 10-K | Annual report | May 31, 2023 | Mar 31, 2023 |
| 8-K |
Current report
Results of operations
|
May 31, 2023 | May 31, 2023 |
| SD | Specialized disclosure (conflict minerals) | May 31, 2023 | — |
| 4 | Insider transaction | Apr 7, 2023 | Apr 5, 2023 |
| 4 | Insider transaction | Apr 7, 2023 | Apr 5, 2023 |
| 4 | Insider transaction | Apr 7, 2023 | Apr 5, 2023 |
| 4 | Insider transaction | Apr 7, 2023 | Apr 5, 2023 |
| 4 | Insider transaction | Apr 7, 2023 | Apr 5, 2023 |
| SC 13G | Ownership over 5% (passive) | Feb 14, 2023 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Feb 8, 2023 | — |
| 10-Q | Quarterly report | Feb 1, 2023 | Dec 31, 2022 |
| 8-K |
Current report
Results of operations
|
Feb 1, 2023 | Feb 1, 2023 |
| SC 13G | Ownership over 5% (passive) | Jan 31, 2023 | — |
| SC 13G/A | Amended ownership over 5% (passive) | Jan 19, 2023 | — |
| 4 | Insider transaction | Dec 19, 2022 | Dec 16, 2022 |
| 4 | Insider transaction | Dec 19, 2022 | Dec 16, 2022 |
| 4 | Insider transaction | Dec 13, 2022 | Dec 12, 2022 |
| S-8 POS | Filing | Nov 17, 2022 | — |
| S-8 POS | Filing | Nov 17, 2022 | — |
| S-8 POS | Filing | Nov 17, 2022 | — |
| S-8 POS | Filing | Nov 17, 2022 | — |
| S-8 POS | Filing | Nov 17, 2022 | — |
| S-8 POS | Filing | Nov 17, 2022 | — |
| 4 | Insider transaction | Nov 2, 2022 | Oct 31, 2022 |
| 10-Q | Quarterly report | Nov 1, 2022 | Sep 30, 2022 |
| 8-K |
Current report
Results of operations
|
Nov 1, 2022 | Nov 1, 2022 |
| 4 | Insider transaction | Oct 21, 2022 | Oct 19, 2022 |
| S-8 | Employee stock plan registration | Aug 10, 2022 | — |
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Company profile
- Industry
- Motors & Generators (SIC 3621)
- Listed as
- AMSC (Nasdaq)
- Fiscal year ends
- March 31
- Incorporated in
- DE
- Headquarters
- Devens, MA
- SEC filer status
- Large accelerated filer
- SEC CIK
- 880807
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Source: SEC EDGAR filings. This is company-reported data, not investment advice.