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Institutional Ownership · SEC Form 13F

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.

243
Institutional holders
33M
Shares held (tracked funds)
69.9%
Of shares outstanding

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).

FundSharesReported value% of valueQuarter
BlackRock, Inc. added3,982,650$135M9.6%2026-Q1
VANGUARD CAPITAL MANAGEMENT LLC new2,039,468$69M4.9%2026-Q1
VANGUARD PORTFOLIO MANAGEMENT LLC new1,711,677$58M4.1%2026-Q1
BAILLIE GIFFORD & CO trimmed1,447,419$49M3.5%2026-Q1
STATE STREET CORP added1,261,071$43M3.0%2026-Q1
GEODE CAPITAL MANAGEMENT, LLC added1,169,152$40M2.8%2026-Q1
BARROW HANLEY MEWHINNEY & STRAUSS LLC new1,139,793$39M2.8%2026-Q1
Nuveen, LLC added1,020,947$35M2.5%2026-Q1
OBERWEIS ASSET MANAGEMENT INC/ added849,900$29M2.1%2026-Q1
AWM Investment Company, Inc. added801,604$27M1.9%2026-Q1
FIRST TRUST ADVISORS LP added778,268$26M1.9%2026-Q1
EMERALD ADVISERS, LLC trimmed757,404$26M1.8%2026-Q1
GOLDMAN SACHS GROUP INC trimmed709,504$24M1.7%2026-Q1
DIMENSIONAL FUND ADVISORS LP added658,297$22M1.6%2026-Q1
MORGAN STANLEY trimmed633,841$21M1.5%2026-Q1
Telemark Asset Management, LLC trimmed600,000$20M1.5%2026-Q1
UBS Group AG trimmed599,821$20M1.4%2026-Q1
D. E. Shaw & Co., Inc. added567,574$19M1.4%2026-Q1
ROYCE & ASSOCIATES LP added542,778$18M1.3%2026-Q1
Legal & General Group Plc added530,131$18M1.3%2026-Q1
ALGERT GLOBAL LLC added489,971$17M1.2%2026-Q1
ARROWSTREET CAPITAL, LIMITED PARTNERSHIP trimmed446,752$15M1.1%2026-Q1
EMERALD MUTUAL FUND ADVISERS TRUST added438,875$15M1.1%2026-Q1
BNP PARIBAS FINANCIAL MARKETS added436,687$15M1.1%2026-Q1
Hood River Capital Management LLC trimmed398,711$13M1.0%2026-Q1
NORTHERN TRUST CORP added393,224$13M1.0%2026-Q1
CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed385,414$13M0.9%2026-Q1
NOMURA ASSET MANAGEMENT INTERNATIONAL INC. trimmed379,483$13M0.9%2026-Q1
Qube Research & Technologies Ltd trimmed329,413$11M0.8%2026-Q1
VANGUARD FIDUCIARY TRUST CO new326,042$11M0.8%2026-Q1
Stephens Investment Management Group LLC added308,515$10M0.7%2026-Q1
Portolan Capital Management, LLC added295,636$10M0.7%2026-Q1
PANAGORA ASSET MANAGEMENT INC added256,392$9M0.6%2026-Q1
ESSEX INVESTMENT MANAGEMENT CO LLC added227,558$8M0.6%2026-Q1
SEI INVESTMENTS CO added224,436$8M0.5%2026-Q1
CITADEL ADVISORS LLC trimmed216,713$7M0.5%2026-Q1
Invesco Ltd. trimmed216,375$7M0.5%2026-Q1
BANK OF AMERICA CORP /DE/ added209,451$7M0.5%2026-Q1
AQR CAPITAL MANAGEMENT LLC added182,305$6M0.4%2026-Q1
TWO SIGMA INVESTMENTS, LP trimmed169,016$6M0.4%2026-Q1
Baird Financial Group, Inc. added163,258$6M0.4%2026-Q1
Palisades Investment Partners, LLC added152,576$5M0.4%2026-Q1
FMR LLC added147,293$5M0.4%2026-Q1
Allspring Global Investments Holdings, LLC trimmed149,601$5M0.3%2026-Q1
BALYASNY ASSET MANAGEMENT L.P. trimmed144,144$5M0.3%2026-Q1
ArrowMark Colorado Holdings LLC added135,432$5M0.3%2026-Q1
Bank of New York Mellon Corp trimmed134,790$5M0.3%2026-Q1
Point72 Asset Management, L.P. added133,800$5M0.3%2026-Q1
JPMORGAN CHASE & CO added136,845$4M0.3%2026-Q1
RAYMOND JAMES FINANCIAL INC trimmed123,954$4M0.3%2026-Q1
GMT Capital Corp108,066$4M0.3%2026-Q1
MILLENNIUM MANAGEMENT LLC added101,576$3M0.2%2026-Q1
AXIOM INVESTORS LLC /DE trimmed100,814$3M0.2%2026-Q1
Swiss National Bank89,100$3M0.2%2026-Q1
UBS AM, a distinct business unit of UBS ASSET MANAGEMENT AMERICAS LLC added88,386$3M0.2%2026-Q1
LPL Financial LLC added87,323$3M0.2%2026-Q1
ALPS ADVISORS INC added86,561$3M0.2%2026-Q1
MACKENZIE FINANCIAL CORP added77,542$3M0.2%2026-Q1
Maxi Investments CY Ltd new75,754$3M0.2%2026-Q1
Lumbard & Kellner, LLC added73,669$2M0.2%2026-Q1
NEW YORK STATE COMMON RETIREMENT FUND70,400$2M0.2%2026-Q1
KENNEDY CAPITAL MANAGEMENT LLC added66,167$2M0.2%2026-Q1
Boston Partners new66,071$2M0.2%2026-Q1
CAMPBELL NEWMAN ASSET MANAGEMENT INC added64,337$2M0.2%2026-Q1
AMERIPRISE FINANCIAL INC added62,336$2M0.2%2026-Q1
SUSQUEHANNA INTERNATIONAL GROUP, LLP trimmed61,814$2M0.1%2026-Q1
RHUMBLINE ADVISERS added59,683$2M0.1%2026-Q1
PRICE T ROWE ASSOCIATES INC /MD/ trimmed58,612$2M0.1%2026-Q1
Amundi added58,169$2M0.1%2026-Q1
WELLS FARGO & COMPANY/MN trimmed58,158$2M0.1%2026-Q1
VANGUARD GROUP INC added3,162,378$91M6.5%2025-Q4 stale
FULLER & THALER ASSET MANAGEMENT, INC. new809,945$48M3.4%2025-Q3 stale
Atreides Management, LP added1,044,193$30M2.1%2025-Q4 stale
MACQUARIE GROUP LTD trimmed465,221$28M2.0%2025-Q3 stale
WELLINGTON MANAGEMENT GROUP LLP trimmed399,246$24M1.7%2025-Q3 stale
Driehaus Capital Management LLC trimmed499,984$14M1.0%2025-Q4 stale
HEIGHTS CAPITAL MANAGEMENT, INC new340,102$12M0.9%2025-Q2 stale
CASTLEARK MANAGEMENT LLC added135,617$8M0.6%2025-Q3 stale
NEXT CENTURY GROWTH INVESTORS LLC new128,220$8M0.5%2025-Q3 stale
TUDOR INVESTMENT CORP ET AL added251,642$7M0.5%2025-Q4 stale
Lisanti Capital Growth, LLC trimmed118,151$7M0.5%2025-Q3 stale
JANE STREET GROUP, LLC added242,767$7M0.5%2025-Q4 stale
Jump Financial, LLC trimmed117,498$7M0.5%2025-Q3 stale
Ghisallo Capital Management LLC trimmed100,000$6M0.4%2025-Q3 stale
Trexquant Investment LP trimmed159,483$6M0.4%2025-Q2 stale
Meridian Wealth Management, LLC new91,102$5M0.4%2025-Q3 stale
Andrew Hill Investment Advisors, Inc. trimmed88,855$5M0.4%2025-Q3 stale
Informed Momentum Co LLC added83,977$5M0.4%2025-Q3 stale
RENAISSANCE TECHNOLOGIES LLC trimmed139,989$4M0.3%2025-Q4 stale
Y-Intercept (Hong Kong) Ltd added120,251$3M0.2%2025-Q4 stale
Penserra Capital Management LLC trimmed57,728$3M0.2%2025-Q3 stale
Cubist Systematic Strategies, LLC added49,508$3M0.2%2025-Q3 stale
CAPITAL FUND MANAGEMENT S.A. added79,160$2M0.2%2025-Q4 stale
Private Advisor Group, LLC added37,683$2M0.2%2025-Q3 stale
HWG Holdings LP new35,468$2M0.2%2025-Q3 stale
Centiva Capital, LP added56,940$2M0.1%2025-Q2 stale
WOLVERINE TRADING, LLC added33,287$2M0.1%2025-Q3 stale
HRT FINANCIAL LP added69,724$2M0.1%2025-Q4 stale
Dynamic Technology Lab Private Ltd added69,225$2M0.1%2025-Q4 stale
Connor, Clark & Lunn Investment Management Ltd. trimmed108,571$2M0.1%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.

HoldersTotal shares

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.

Learn how to read institutional ownership