American Superconductor Corporation (AMSC) ownership: Top institutional holder: BlackRock, Inc. ($134.81M). Insider activity: Net Seller (0 buys, 20 sells). SEC EDGAR first-party data.
| Holder | Shares | Market Value | Reported |
|---|---|---|---|
| BlackRock, Inc. | 3982650.00 | $134.81M | 2026-03-31 |
| VANGUARD GROUP INC | 3526632.00 | $101.50M | 2025-12-31 |
| VANGUARD CAPITAL MANAGEMENT LLC | 2039468.00 | $69.04M | 2026-03-31 |
| VANGUARD PORTFOLIO MANAGEMENT LLC | 1711677.00 | $57.94M | 2026-03-31 |
| BAILLIE GIFFORD & CO | 1447419.00 | $49.00M | 2026-03-31 |
| STATE STREET CORP | 1261071.00 | $42.69M | 2026-03-31 |
| GEODE CAPITAL MANAGEMENT, LLC | 1169152.00 | $39.58M | 2026-03-31 |
| BARROW HANLEY MEWHINNEY & STRAUSS LLC | 1139793.00 | $38.58M | 2026-03-31 |
| Insider | Transaction | Value | Date |
|---|---|---|---|
| Sell | null | 2026-06-11 | |
| Sell | null | 2026-06-11 | |
| Sell | null | 2026-06-11 | |
| Sell | null | 2026-06-11 | |
| Sell | null | 2026-06-11 | |
| Sell | null | 2026-06-08 | |
| Sell | null | 2026-06-08 | |
| Sell | null | 2026-06-08 |
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Institutional data from SEC Form 13F. Insider data from SEC Form 4. Congressional data from STOCK Act disclosures. Not personalized investment advice.