Comparable stake leader
BlackRock, Inc.
SEC ownership of AMERICAN SUPERCONDUCTOR CORP /DE/
Top holders, 13D/G large-stake signals, insider positions, and transaction flow tied to CIK 0000880807.
Disclosed value leader
BlackRock, Inc.
Comparable rows
50/50
Latest evidence
30 Jun 2026
- Public ticker
- AMSC on Nasdaq
- Parsed ownership sources
-
13F, 13D/G, and 3/4/5
Source: Parsed SEC ownership filingsUse: Compare filing families carefully
- Largest SEC-reported holder
-
BlackRock, Inc.
Ranking: Comparable ownership first, then disclosed value
- Comparable ownership rows
-
50 of 50
Meaning: Rows with safely comparable ownership %
- Latest 13D/G holder
-
BlackRock, Inc.
Source: Latest parsed Schedule 13D/G stake
- Latest parsed ownership date
-
30 Jun 2026
Freshness: Most recent filing date in this holder set
- Issuer CIK
- 0000880807
- Issuer location
- Devens, MA
Ownership snapshot
CIK-linked ownership evidence from parsed SEC filings.
3 signals
Issuer
Names, identifiers, and filing context for this profile.
2 identity fields
Ownership snapshot
Top shareholders of AMERICAN SUPERCONDUCTOR CORP /DE/ (13F + 13D/G + 3/4/5)
Grouped by holder across the latest SEC ownership disclosures. Start with comparable ownership when available, then verify the linked 13F, 13D/G, or 3/4/5 evidence.
Comparable stake leader
BlackRock, Inc.
Disclosed value leader
BlackRock, Inc.
Comparable rows
50/50
Latest evidence
30 Jun 2026
13F
13D/G
3/4/5
Lead comparable stake: 7.1%
13D/G row: BlackRock, Inc.
Showing 1-8 of 50 holder rows.
Quick read
BlackRock, Inc. leads the comparable SEC ownership view at 7.1%.
50 of 50 rows have a safely comparable ownership percentage. Use this as a filing-backed starting point, then open the detailed table for source links, reporting role, position value, share count, and filing date.
Open SEC evidence
Opens BlackRock, Inc.'s linked filing trail.
Comparable ownership
Top 5
BlackRock, Inc.
7.1%
VANGUARD CAPITAL MANAGEMENT LLC
4.9%
BAILLIE GIFFORD & CO
4.2%
Daniel P. McGahn
2.4%
John W. Kosiba Jr.
0.69%
Ownership % is shown only when SEC disclosures are safely comparable across share classes.
Detailed SEC evidence table Showing 1-8 of 50 holder rows
| Holder | Evidence | Ownership % | Position | 12M Net Δ | As of |
|---|---|---|---|---|---|
| BlackRock, Inc. |
13F
13D/G
Company
|
7.1%
from 13D/G
|
$169,998,850
4,095,371 shares
|
— | 30 Jun 2026 |
| VANGUARD CAPITAL MANAGEMENT LLC |
13D/G
13F
Vanguard Capital Management · Company
|
4.9%
|
$85,959,683
2,390,425 shares
|
+$204,576 | 30 Jun 2026 |
| BAILLIE GIFFORD & CO |
13F
13D/G
Company
|
4.2%
from 13D/G
|
$38,741,615
933,308 shares
|
— | 30 Jun 2026 |
| Daniel P. McGahn |
3/4/5
Chairman, President and CEO, Director
|
2.4%
|
$43,296,451
1,145,273 shares
|
-$5,320,652 | 11 Jun 2026 |
| John W. Kosiba Jr. |
3/4/5
SVP, CFO & Treasurer
|
0.69%
|
$12,669,262
334,748 shares
|
-$2,317,580 | 11 Jun 2026 |
| David R. Oliver Jr. |
3/4/5
Director
|
0.13%
|
$2,160,402
63,823 shares
|
-$6,820 | 03 Apr 2026 |
| Arthur H. House |
3/4/5
Director
|
0.11%
|
$1,752,713
51,779 shares
|
— | 03 Apr 2026 |
| Barbara G. Littlefield |
3/4/5
Director
|
0.07%
|
$1,199,200
35,427 shares
|
— | 03 Apr 2026 |
How to read this table
Rows are grouped by holder and ranked first by SEC-reported ownership % when it is safely comparable, then by disclosed holdings value. — indicates unavailable or non-comparable values; "mixed-class rows" means the latest filing spans non-comparable classes.
Forms 3/4/5 flow
Insider trading overview
Net insider flow leans to selling over the last 12 months. Net value: -$7,795,573.
Buys
$0
Insiders: 0
Sells
$7,795,573
Insiders: 4
Net
-$7,795,573
Shares: -163,918
Window
Last 12 months
4 rolling buckets
Buy value
Sell value
Shares: 0
Shares: 163,918
| Window (months) | Buy shares | Sell shares | Buy value | Sell value | Net value |
|---|---|---|---|---|---|
| 0-3 | 0 | 41,391 | $0 | $1,613,564 | -$1,613,564 |
| 3-6 | 0 | 122,327 | $0 | $6,175,188 | -$6,175,188 |
| 6-9 | 0 | 200 | $0 | $6,820 | -$6,820 |
| 9-12 | 0 | 0 | $0 | $0 | $0 |
Reporting owners
Insider holders from Forms 3/4/5
Showing 1-9 of 9 reporting-owner rows connected to AMERICAN SUPERCONDUCTOR CORP /DE/. Open a relationship link for the CIK-to-CIK filing trail.
Rows
9
Largest Forms 3/4/5 holder
Daniel P. McGahn
Net 12M change
-$7,795,572
Latest report
11 Jun 2026
| Name | Relationship | Holdings Value | Past Year Net Change | Change % | Valuation | Report Date |
|---|---|---|---|---|---|---|
| Daniel P. McGahn | Chairman, President and CEO, Director | $43,296,451 | -$5,320,652 | -11% | Mixed | 11 Jun 2026 |
| John W. Kosiba Jr. | SVP, CFO & Treasurer | $12,669,262 | -$2,317,580 | -15% | Mixed | 11 Jun 2026 |
| David R. Oliver Jr. | Director | $2,160,402 | -$6,820 | -0.31% | Mixed | 03 Apr 2026 |
| Arthur H. House | Director | $1,752,713 | Mixed | 03 Apr 2026 | ||
| Barbara G. Littlefield | Director | $1,199,200 | Mixed | 03 Apr 2026 | ||
| Margaret D. Klein | Director | $659,802 | Mixed | 03 Apr 2026 | ||
| Laura A. Dambier | Director | $564,148 | -$150,520 | -21% | Filing P/S | 11 Jun 2026 |
| Vikram S. Budhraja | Director | $352,876 | Mixed | 10 Jun 2022 | ||
| Terence Robert Donnelly | Director | $90,209 | Mixed | 03 Apr 2026 |
Recent insider transactions for AMERICAN SUPERCONDUCTOR CORP /DE/
Showing up to 300 recent insider transactions from the last 12 months.
| Insider | Symbol | Class | Transaction | % | SEC-reported value | SEC-reported price | Shares | Shares owned | Date | Ownership |
|---|---|---|---|---|---|---|---|---|---|---|
| Laura A. Dambier | AMSC | Common Stock | Sale | -21.1% | $150,520 | $37.63 | -4,000 | 14,992 | 11 Jun 2026 | Direct |
| John W. Kosiba Jr. | AMSC | Common Stock | Sale | -1.98% | $253,579 | $37.46 | -6,769 | 334,377 | 11 Jun 2026 | Direct |
| Daniel P. McGahn | AMSC | Common Stock | Sale | -1.4% | $603,503 | $37.45 | -16,117 | 1,131,929 | 11 Jun 2026 | Direct |
| John W. Kosiba Jr. | AMSC | Common Stock | Sale | -1.4% | $201,967 | $41.77 | -4,835 | 341,146 | 08 Jun 2026 | Direct |
| Daniel P. McGahn | AMSC | Common Stock | Sale | -0.84% | $403,996 | $41.78 | -9,670 | 1,148,046 | 08 Jun 2026 | Direct |
| John W. Kosiba Jr. | AMSC | Common Stock | Sale | -1.83% | $315,548 | $48.94 | -6,447 | 345,981 | 03 Jun 2026 | Direct |
| Daniel P. McGahn | AMSC | Common Stock | Sale | -1.1% | $630,265 | $48.88 | -12,893 | 1,157,716 | 03 Jun 2026 | Direct |
| John W. Kosiba Jr. | AMSC | Common Stock | Sale | -7.96% | $1,546,486 | $50.77 | -30,462 | 352,428 | 02 Jun 2026 | Direct |
| Daniel P. McGahn | AMSC | Common Stock | Sale | -5.83% | $3,682,889 | $50.78 | -72,525 | 1,170,609 | 02 Jun 2026 | Direct |
| John W. Kosiba Jr. | AMSC | Common Stock | Award | 8.5% | 30,000 | 382,890 | 01 Jun 2026 | Direct | ||
| Daniel P. McGahn | AMSC | Common Stock | Award | 5.07% | 60,000 | 1,243,134 | 01 Jun 2026 | Direct | ||
| Terence Robert Donnelly | AMSC | Common Stock | Award | 2,665 | 2,665 | 03 Apr 2026 | Direct | |||
| David R. Oliver Jr. | AMSC | Common Stock | Award | 5.13% | 3,116 | 63,823 | 03 Apr 2026 | Direct | ||
| Barbara G. Littlefield | AMSC | Common Stock | Award | 9.64% | 3,116 | 35,427 | 03 Apr 2026 | Direct | ||
| Margaret D. Klein | AMSC | Common Stock | Award | 19% | 3,116 | 19,492 | 03 Apr 2026 | Direct | ||
| Arthur H. House | AMSC | Common Stock | Award | 6.4% | 3,116 | 51,779 | 03 Apr 2026 | Direct | ||
| Laura A. Dambier | AMSC | Common Stock | Award | 19.6% | 3,116 | 18,992 | 03 Apr 2026 | Direct | ||
| David R. Oliver Jr. | AMSC | Common Stock | Sale | -0.33% | $6,820 | $34.10 | -200 | 60,707 | 24 Feb 2026 | Direct |
* marks a reported price that did not pass the local price check.