Aspen Aerogels, Inc.
Aspen Aerogels, Inc. (ASPN) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · ASPN · as of Sep 30, 2025
Ownership Breakdown
217
Institutional Holders
▲ 19 vs Q2
$497.24M
Total Inst. Value
▲ $73.44M vs Q2
82.88M
Shares Outstanding
freeFloat 92.57%
71.43M
13F Shares Held
▼ 74,008 vs Q2
Institutional ownership = 13F shares ÷ total outstanding. Insider % = 100 − free float. Public % = free float − institution %. Data: FMP /symbol-positions-summary + /shares-float + SEC EDGAR.
Top Institutional Holders
ASPN largest shareholders · institutional ownership
Q3 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
KIM, LLC wholesale-lumber & other construction materials | 12.28M | 14.94% | 14.94% | $85.47B | Nov 12, 2025 | — held |
BLACKROCK, INC. wholesale-lumber & other construction materials | 4.98M | 6.06% | 6.06% | $34.64B | Nov 12, 2025 | ▲ 372 |
VANGUARD GROUP INC wholesale-lumber & other construction materials | 4.51M | 5.49% | 5.49% | $31.39B | Nov 7, 2025 | ▲ 22.7K |
OAKTOP CAPITAL MANAGEMENT II, L.P. wholesale-lumber & other construction materials | 4.39M | 5.35% | 5.35% | $30.59B | Nov 14, 2025 | — held |
NEEDHAM INVESTMENT MANAGEMENT LLC wholesale-lumber & other construction materials | 3.44M | 4.19% | 4.19% | $23.94B | Nov 14, 2025 | ▲ 425.5K |
GEORGE KAISER FAMILY FOUNDATION wholesale-lumber & other construction materials | 3.17M | 3.85% | 3.85% | $22.04B | Nov 12, 2025 | — held |
DIMENSIONAL FUND ADVISORS LP wholesale-lumber & other construction materials | 2.25M | 2.74% | 2.74% | $15.67B | Nov 12, 2025 | ▼ 197.1K |
STATE STREET CORP wholesale-lumber & other construction materials | 1.94M | 2.37% | 2.37% | $13.53B | Nov 14, 2025 | ▲ 23.6K |
TELEMARK ASSET MANAGEMENT, LLC wholesale-lumber & other construction materials | 1.79M | 2.18% | 2.18% | $12.48B | Nov 10, 2025 | — held |
GAGNON SECURITIES LLC wholesale-lumber & other construction materials | 1.75M | 2.14% | 2.14% | $12.21B | Nov 3, 2025 | ▼ 144.3K |
Data from SEC Form 13F filings. Ownership bar normalised to largest holder. Change flags: isNew / isSoldOut / changeInSharesNumber (FMP extract-analytics/holder).
Institutional Activity
Q3 2025 vs prior quarter
Q3 2025
24
Increased
+5.64M shares3
New Positions
first time holders18
Decreased
−4.29M shares0
Sold Out
fully exitedNet shares change (top 50)
+1.35M
+5.64M / −4.29M
Net new holders
+9
3 new / 0 exited
Based on top 50 institutional holders by position size. Fields: isNew, isSoldOut, changeInSharesNumber (FMP extract-analytics/holder, limit=50).
Insider Buying vs Selling
ASPN insider trading · insider activity
Source: SEC Form 4
0
Buy transactions
0
Sell transactions
0.00
Buy/Sell ratio
$0M
Total disposed
Recent Insider Transactions
Showing 10 most recent · Common Stock only
| Name · Role | Date | Type | Shares | Price | Value | After Trans. | Filing |
|---|---|---|---|---|---|---|---|
Mitchell Steven R director | May 13, 2026 | Award | 10,370 | — | — | 156.9K | Form 4 ↗ |
Mitchell Steven R director | May 13, 2026 | Award | 8,706 | $5.40 | $47.0K | 8.7K | Form 4 ↗ |
SWEETNAM JAMES E director | May 13, 2026 | Award | 10,370 | — | — | 36.3K | Form 4 ↗ |
SWEETNAM JAMES E director | May 13, 2026 | Award | 8,706 | $5.40 | $47.0K | 8.7K | Form 4 ↗ |
NOGLOWS WILLIAM P director | May 13, 2026 | Award | 10,370 | — | — | 99.4K | Form 4 ↗ |
NOGLOWS WILLIAM P director | May 13, 2026 | Award | 8,706 | $5.40 | $47.0K | 8.7K | Form 4 ↗ |
Kool Kathleen director | May 13, 2026 | Award | 10,370 | — | — | 34.3K | Form 4 ↗ |
Kool Kathleen director | May 13, 2026 | Award | 8,706 | $5.40 | $47.0K | 8.7K | Form 4 ↗ |
Robinson Cari director | May 13, 2026 | Award | 10,370 | — | — | 22.6K | Form 4 ↗ |
Robinson Cari director | May 13, 2026 | Award | 8,706 | $5.40 | $47.0K | 8.7K | Form 4 ↗ |
Source: /insider-trading/search (FMP stable). Buy/Sell direction: acquisitionOrDisposition A=Buy, D=Sell. RSU vesting (M-Exempt) excluded from sentiment bar. All data from SEC EDGAR public filings.
About institutional & insider ownership
Aspen Aerogels, Inc. (ASPN) is primarily owned by institutional investors, who hold approximately 86.2% of total shares outstanding. Company insiders own approximately 7.43%, while retail and public investors account for the remaining 6.38%.
The largest institutional shareholder of Aspen Aerogels, Inc. is KIM, LLC, holding approximately 12.28 million shares — equal to 14.94% of outstanding shares — as of September 30, 2025.
A total of 217 institutional investors currently hold ASPN stock, with a combined institutional value of approximately $497,238,664 as of the most recent 13F filing period.
Frequently asked questions
ASPN ownershipAspen Aerogels, Inc. (ASPN) is primarily owned by institutional investors, who hold approximately 86.2% of shares. The largest shareholder is KIM, LLC with a 14.94% stake. Company insiders hold 7.43%. Data sourced from SEC Form 13F as of September 30, 2025.