American Superconductor Corp
AMSC- Exchange
- Nasdaq
- Industry
- Motors & Generators
- SEC CIK
- 0000880807
No open-market purchases or sales by American Superconductor Corp insiders were filed in the last 90 days; 277 institutions reported holding it in 13F filings for Q2 2026, worth $1.47B in total; no superinvestor holds it.
Holders of 5% or more of AMSC
Holders whose latest Schedule 13D or 13G filing reports 5% or more of American Superconductor Corp, largest stake first. The change is against the holder's previous filing.
| Holder | Latest form | Stake | Change | First filed | Latest filing | Filing |
|---|---|---|---|---|---|---|
| BlackRock, Inc. | 13G/A | 7.10%2.80M shares | −1.60 ppfrom 8.70% | Feb 5, 20252 filings | Apr 17, 2025 | SEC |
Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.
13D and 13G filings
6 Schedule 13D and 13G filings on American Superconductor Corp, newest first, including old-format filings without a stake.
| Filed (ET) | Filer | Form | Stake | Change | Event date | Filing |
|---|---|---|---|---|---|---|
| Apr 29, 20264:34 PM ET | Vanguard Capital Management LLC | 13G | 5.00%2.38M shares | New | Mar 31, 2026 | SEC |
| Mar 26, 20263:42 PM ET | Vanguard Group Inc | 13G/A | 0.00%0 shares | −7.40 ppfrom 7.40%Below 5% | Mar 13, 2026 | SEC |
| Jan 30, 20261:29 PM ET | Vanguard Group Inc | 13G/A | 7.40%3.53M shares | – | Dec 31, 2025 | SEC |
| Apr 17, 20259:35 AM ET | BlackRock, Inc. | 13G/A | 7.10%2.80M shares | −1.60 ppfrom 8.70% | Mar 31, 2025 | SEC |
| Feb 12, 202510:33 AM ET | Baillie Gifford & Co | 13G/A | 4.20%1.65M shares | −1.30 ppfrom 5.50%Below 5% | Dec 31, 2024 | SEC |
| Feb 5, 20255:28 PM ET | BlackRock, Inc. | 13G/A | 8.70%3.43M shares | – | Dec 31, 2024 | SEC |
| Nov 4, 202410:06 AM ET | Baillie Gifford & Co | 13G/A | 5.50%2.11M shares | – | Sep 30, 2024 | SEC |
Form 144: proposed insider sales
Notices from officers, directors and other affiliates planning to sell American Superconductor Corp shares.
No Form 144 notices for American Superconductor Corp are on file.