Who owns American Superconductor Corporation (AMSC)
Which tracked institutional funds hold AMSC, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See AMSC company fundamentals →
Ownership as of the 2026-Q1 13F filings (latest filed 2026-05-18). 13F is disclosed up to 45 days after quarter-end, so the most recent quarter fills in over the following weeks.
How the tape is positioned
83 tracked funds added or opened AMSC while 46 trimmed or exited it between 2025-Q4 and 2026-Q1 — the tape is split. When large holders disagree on a name, the funds moving first are sometimes ahead of the story.
A prompt to read the filings, not a verdict. 13F is a quarter-end snapshot disclosed up to 45 days late; a fund adds or exits for mandate, benchmark, and timing reasons that have nothing to do with a view on the stock. This is a starting question, not a signal to trade.
Conviction spread
AMSC’s largest tracked holder by dollar value, BlackRock, Inc., sizes it at 0.0% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 0.0pp gap the other way — the median holder sizes AMSC more heavily than its largest holder by dollar value does.
Book-share is each fund’s reported value in AMSC divided by its whole reported 13F book, so it is comparable across funds of different sizes and is unaffected by stock splits. A higher share means a fund has committed more of its book to the name — a starting question about conviction, not a verdict or a signal to trade.
Institutional & insider positioning
Between 2025-Q4 and 2026-Q1, across 243 tracked filers holding AMSC, 154 increased or opened the position and 111 reduced or closed it; over the same quarter, open-market insider Form 4 buying and selling roughly offset.
This fuses two public signals for the same quarter — how tracked institutions changed their positions and whether insiders bought or sold in the open market. It describes what was filed; it is a starting question, not a verdict or a signal to trade.
New buyers & exits
Funds opening or closing a position in AMSC between the 2025-Q4 and 2026-Q1 13F filings, and the largest changes among funds holding it in both. New buyers and exits are counted on fund presence (split-invariant); adds and trims are measured on reported value.
New buyers 19
- VANGUARD CAPITAL MANAGEMENT LLC$69M
- VANGUARD PORTFOLIO MANAGEMENT LLC$58M
- BARROW HANLEY MEWHINNEY & STRAUSS LLC$39M
- Hood River Capital Management LLC$13M
- VANGUARD FIDUCIARY TRUST CO$11M
- Portolan Capital Management, LLC$10M
Full exits 27
- VANGUARD GROUP INC$91M
- Atreides Management, LP$30M
- Driehaus Capital Management LLC$14M
- TUDOR INVESTMENT CORP ET AL$7M
- JANE STREET GROUP, LLC$7M
- RENAISSANCE TECHNOLOGIES LLC$4M
Largest adds
- BlackRock, Inc.$27M
- BNP PARIBAS FINANCIAL MARKETS$12M
- Legal & General Group Plc$10M
- STATE STREET CORP$8M
- GEODE CAPITAL MANAGEMENT, LLC$8M
- ROYCE & ASSOCIATES LP$7M
Largest trims
- Qube Research & Technologies Ltd$6M
- PRICE T ROWE ASSOCIATES INC /MD/$6M
- ARROWSTREET CAPITAL, LIMITED PARTNERSHIP$5M
- Invesco Ltd.$4M
- TWO SIGMA INVESTMENTS, LP$4M
- CITADEL ADVISORS LLC$2M
Institutional holders
One row per tracked fund, largest reported value first. “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding. Rows marked stale are from an earlier filing than the security’s latest quarter — that fund is absent from the newest snapshot (position exited, or reported under a different name).
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| BlackRock, Inc. added | 3,982,650 | $135M | 9.6% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 2,039,468 | $69M | 4.9% | 2026-Q1 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 1,711,677 | $58M | 4.1% | 2026-Q1 |
| BAILLIE GIFFORD & CO trimmed | 1,447,419 | $49M | 3.5% | 2026-Q1 |
| STATE STREET CORP added | 1,261,071 | $43M | 3.0% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 1,169,152 | $40M | 2.8% | 2026-Q1 |
| BARROW HANLEY MEWHINNEY & STRAUSS LLC new | 1,139,793 | $39M | 2.8% | 2026-Q1 |
| Nuveen, LLC added | 1,020,947 | $35M | 2.5% | 2026-Q1 |
| OBERWEIS ASSET MANAGEMENT INC/ added | 849,900 | $29M | 2.1% | 2026-Q1 |
| AWM Investment Company, Inc. added | 801,604 | $27M | 1.9% | 2026-Q1 |
| FIRST TRUST ADVISORS LP added | 778,268 | $26M | 1.9% | 2026-Q1 |
| EMERALD ADVISERS, LLC trimmed | 757,404 | $26M | 1.8% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC trimmed | 709,504 | $24M | 1.7% | 2026-Q1 |
| DIMENSIONAL FUND ADVISORS LP added | 658,297 | $22M | 1.6% | 2026-Q1 |
| MORGAN STANLEY trimmed | 633,841 | $21M | 1.5% | 2026-Q1 |
| Telemark Asset Management, LLC trimmed | 600,000 | $20M | 1.5% | 2026-Q1 |
| UBS Group AG trimmed | 599,821 | $20M | 1.4% | 2026-Q1 |
| D. E. Shaw & Co., Inc. added | 567,574 | $19M | 1.4% | 2026-Q1 |
| ROYCE & ASSOCIATES LP added | 542,778 | $18M | 1.3% | 2026-Q1 |
| Legal & General Group Plc added | 530,131 | $18M | 1.3% | 2026-Q1 |
| ALGERT GLOBAL LLC added | 489,971 | $17M | 1.2% | 2026-Q1 |
| ARROWSTREET CAPITAL, LIMITED PARTNERSHIP trimmed | 446,752 | $15M | 1.1% | 2026-Q1 |
| EMERALD MUTUAL FUND ADVISERS TRUST added | 438,875 | $15M | 1.1% | 2026-Q1 |
| BNP PARIBAS FINANCIAL MARKETS added | 436,687 | $15M | 1.1% | 2026-Q1 |
| Hood River Capital Management LLC trimmed | 398,711 | $13M | 1.0% | 2026-Q1 |
| NORTHERN TRUST CORP added | 393,224 | $13M | 1.0% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed | 385,414 | $13M | 0.9% | 2026-Q1 |
| NOMURA ASSET MANAGEMENT INTERNATIONAL INC. trimmed | 379,483 | $13M | 0.9% | 2026-Q1 |
| Qube Research & Technologies Ltd trimmed | 329,413 | $11M | 0.8% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 326,042 | $11M | 0.8% | 2026-Q1 |
| Stephens Investment Management Group LLC added | 308,515 | $10M | 0.7% | 2026-Q1 |
| Portolan Capital Management, LLC added | 295,636 | $10M | 0.7% | 2026-Q1 |
| PANAGORA ASSET MANAGEMENT INC added | 256,392 | $9M | 0.6% | 2026-Q1 |
| ESSEX INVESTMENT MANAGEMENT CO LLC added | 227,558 | $8M | 0.6% | 2026-Q1 |
| SEI INVESTMENTS CO added | 224,436 | $8M | 0.5% | 2026-Q1 |
| CITADEL ADVISORS LLC trimmed | 216,713 | $7M | 0.5% | 2026-Q1 |
| Invesco Ltd. trimmed | 216,375 | $7M | 0.5% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 209,451 | $7M | 0.5% | 2026-Q1 |
| AQR CAPITAL MANAGEMENT LLC added | 182,305 | $6M | 0.4% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP trimmed | 169,016 | $6M | 0.4% | 2026-Q1 |
| Baird Financial Group, Inc. added | 163,258 | $6M | 0.4% | 2026-Q1 |
| Palisades Investment Partners, LLC added | 152,576 | $5M | 0.4% | 2026-Q1 |
| FMR LLC added | 147,293 | $5M | 0.4% | 2026-Q1 |
| Allspring Global Investments Holdings, LLC trimmed | 149,601 | $5M | 0.3% | 2026-Q1 |
| BALYASNY ASSET MANAGEMENT L.P. trimmed | 144,144 | $5M | 0.3% | 2026-Q1 |
| ArrowMark Colorado Holdings LLC added | 135,432 | $5M | 0.3% | 2026-Q1 |
| Bank of New York Mellon Corp trimmed | 134,790 | $5M | 0.3% | 2026-Q1 |
| Point72 Asset Management, L.P. added | 133,800 | $5M | 0.3% | 2026-Q1 |
| JPMORGAN CHASE & CO added | 136,845 | $4M | 0.3% | 2026-Q1 |
| RAYMOND JAMES FINANCIAL INC trimmed | 123,954 | $4M | 0.3% | 2026-Q1 |
| GMT Capital Corp | 108,066 | $4M | 0.3% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC added | 101,576 | $3M | 0.2% | 2026-Q1 |
| AXIOM INVESTORS LLC /DE trimmed | 100,814 | $3M | 0.2% | 2026-Q1 |
| Swiss National Bank | 89,100 | $3M | 0.2% | 2026-Q1 |
| UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC added | 88,386 | $3M | 0.2% | 2026-Q1 |
| LPL Financial LLC added | 87,323 | $3M | 0.2% | 2026-Q1 |
| ALPS ADVISORS INC added | 86,561 | $3M | 0.2% | 2026-Q1 |
| MACKENZIE FINANCIAL CORP added | 77,542 | $3M | 0.2% | 2026-Q1 |
| Maxi Investments CY Ltd new | 75,754 | $3M | 0.2% | 2026-Q1 |
| Lumbard & Kellner, LLC added | 73,669 | $2M | 0.2% | 2026-Q1 |
| NEW YORK STATE COMMON RETIREMENT FUND | 70,400 | $2M | 0.2% | 2026-Q1 |
| KENNEDY CAPITAL MANAGEMENT LLC added | 66,167 | $2M | 0.2% | 2026-Q1 |
| Boston Partners new | 66,071 | $2M | 0.2% | 2026-Q1 |
| CAMPBELL NEWMAN ASSET MANAGEMENT INC added | 64,337 | $2M | 0.2% | 2026-Q1 |
| AMERIPRISE FINANCIAL INC added | 62,336 | $2M | 0.2% | 2026-Q1 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP trimmed | 61,814 | $2M | 0.1% | 2026-Q1 |
| RHUMBLINE ADVISERS added | 59,683 | $2M | 0.1% | 2026-Q1 |
| PRICE T ROWE ASSOCIATES INC /MD/ trimmed | 58,612 | $2M | 0.1% | 2026-Q1 |
| Amundi added | 58,169 | $2M | 0.1% | 2026-Q1 |
| WELLS FARGO & COMPANY/MN trimmed | 58,158 | $2M | 0.1% | 2026-Q1 |
| VANGUARD GROUP INC added | 3,162,378 | $91M | 6.5% | 2025-Q4 stale |
| FULLER & THALER ASSET MANAGEMENT, INC. new | 809,945 | $48M | 3.4% | 2025-Q3 stale |
| Atreides Management, LP added | 1,044,193 | $30M | 2.1% | 2025-Q4 stale |
| MACQUARIE GROUP LTD trimmed | 465,221 | $28M | 2.0% | 2025-Q3 stale |
| WELLINGTON MANAGEMENT GROUP LLP trimmed | 399,246 | $24M | 1.7% | 2025-Q3 stale |
| Driehaus Capital Management LLC trimmed | 499,984 | $14M | 1.0% | 2025-Q4 stale |
| HEIGHTS CAPITAL MANAGEMENT, INC new | 340,102 | $12M | 0.9% | 2025-Q2 stale |
| CASTLEARK MANAGEMENT LLC added | 135,617 | $8M | 0.6% | 2025-Q3 stale |
| NEXT CENTURY GROWTH INVESTORS LLC new | 128,220 | $8M | 0.5% | 2025-Q3 stale |
| TUDOR INVESTMENT CORP ET AL added | 251,642 | $7M | 0.5% | 2025-Q4 stale |
| Lisanti Capital Growth, LLC trimmed | 118,151 | $7M | 0.5% | 2025-Q3 stale |
| JANE STREET GROUP, LLC added | 242,767 | $7M | 0.5% | 2025-Q4 stale |
| Jump Financial, LLC trimmed | 117,498 | $7M | 0.5% | 2025-Q3 stale |
| Ghisallo Capital Management LLC trimmed | 100,000 | $6M | 0.4% | 2025-Q3 stale |
| Trexquant Investment LP trimmed | 159,483 | $6M | 0.4% | 2025-Q2 stale |
| Meridian Wealth Management, LLC new | 91,102 | $5M | 0.4% | 2025-Q3 stale |
| Andrew Hill Investment Advisors, Inc. trimmed | 88,855 | $5M | 0.4% | 2025-Q3 stale |
| Informed Momentum Co LLC added | 83,977 | $5M | 0.4% | 2025-Q3 stale |
| RENAISSANCE TECHNOLOGIES LLC trimmed | 139,989 | $4M | 0.3% | 2025-Q4 stale |
| Y-Intercept (Hong Kong) Ltd added | 120,251 | $3M | 0.2% | 2025-Q4 stale |
| Penserra Capital Management LLC trimmed | 57,728 | $3M | 0.2% | 2025-Q3 stale |
| Cubist Systematic Strategies, LLC added | 49,508 | $3M | 0.2% | 2025-Q3 stale |
| CAPITAL FUND MANAGEMENT S.A. added | 79,160 | $2M | 0.2% | 2025-Q4 stale |
| Private Advisor Group, LLC added | 37,683 | $2M | 0.2% | 2025-Q3 stale |
| HWG Holdings LP new | 35,468 | $2M | 0.2% | 2025-Q3 stale |
| Centiva Capital, LP added | 56,940 | $2M | 0.1% | 2025-Q2 stale |
| WOLVERINE TRADING, LLC added | 33,287 | $2M | 0.1% | 2025-Q3 stale |
| HRT FINANCIAL LP added | 69,724 | $2M | 0.1% | 2025-Q4 stale |
| Dynamic Technology Lab Private Ltd added | 69,225 | $2M | 0.1% | 2025-Q4 stale |
| Connor, Clark & Lunn Investment Management Ltd. trimmed | 108,571 | $2M | 0.1% | 2025-Q1 stale |
Ownership over time
Tracked institutional holder count and total shares held by filing quarter (independent scales). The curated-era tail and any mid-ingest latest quarter are handled honestly — a partial quarter is not drawn as a collapse.
Reading this table
Funds hold the same stock for different reasons — an index fund “holds” almost everything, an active manager sizes a name to a mandate and a benchmark, and each fund entered at its own price and time. Because 13F is filed up to 45 days after quarter-end, every row is a backward-looking snapshot; a manager may have traded since. Share-class siblings (a company’s A and C shares) are rolled up to one line so a dual-class name is never double-counted. Compare like-for-like. A large holder is not an endorsement, and a fund exiting is not a warning — this is a starting question, not a verdict.
About 13F filings
A Form 13F is a quarterly disclosure that institutional investment managers with over $100 million in US-listed equities must file with the SEC. In plain English: it is a snapshot of the long stock positions a fund held at the end of a quarter. It covers long US-listed equities only — not short positions, options, cash, or private holdings — and the funds shown are the large sample we track, not the complete 13F universe.