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 Mar 31, 2025
Ownership Breakdown
236
Institutional Holders
▼ 20 vs Q4
$457.87M
Total Inst. Value
▼ $409.79M vs Q4
82.88M
Shares Outstanding
freeFloat 92.57%
71.32M
13F Shares Held
▼ 1.66M vs Q4
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
Q1 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
KIM, LLC wholesale-lumber & other construction materials | 12.28M | 14.96% | 14.96% | $78.47B | May 9, 2025 | — held |
BLACKROCK, INC. wholesale-lumber & other construction materials | 4.96M | 6.04% | 6.04% | $31.70B | May 2, 2025 | ▼ 41.0K |
OAKTOP CAPITAL MANAGEMENT II, L.P. wholesale-lumber & other construction materials | 4.39M | 5.35% | 5.35% | $28.08B | May 15, 2025 | ▲ 654.0K |
VANGUARD GROUP INC wholesale-lumber & other construction materials | 4.37M | 5.33% | 5.33% | $27.94B | May 9, 2025 | ▲ 12.9K |
GEORGE KAISER FAMILY FOUNDATION wholesale-lumber & other construction materials | 3.17M | 3.86% | 3.86% | $20.24B | May 13, 2025 | — held |
NEEDHAM INVESTMENT MANAGEMENT LLC wholesale-lumber & other construction materials | 2.74M | 3.34% | 3.34% | $17.49B | May 15, 2025 | ▲ 347.5K |
DIMENSIONAL FUND ADVISORS LP wholesale-lumber & other construction materials | 2.51M | 3.06% | 3.06% | $16.02B | May 13, 2025 | ▲ 489.0K |
AWM INVESTMENT COMPANY, INC. wholesale-lumber & other construction materials | 2.45M | 2.98% | 2.98% | $15.65B | May 15, 2025 | ▲ 1.24M |
TELEMARK ASSET MANAGEMENT, LLC wholesale-lumber & other construction materials | 1.89M | 2.31% | 2.31% | $12.09B | May 12, 2025 | — held |
MILLENNIUM MANAGEMENT LLC wholesale-lumber & other construction materials | 1.60M | 1.95% | 1.95% | $10.22B | May 15, 2025 | ▼ 22.6K |
Data from SEC Form 13F filings. Ownership bar normalised to largest holder. Change flags: isNew / isSoldOut / changeInSharesNumber (FMP extract-analytics/holder).
Institutional Activity
Q1 2025 vs prior quarter
Q1 2025
27
Increased
+8.23M shares1
New Positions
first time holders19
Decreased
−2.33M shares0
Sold Out
fully exitedNet shares change (top 50)
+5.90M
+8.23M / −2.33M
Net new holders
+9
1 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 86.1% of total shares outstanding. Company insiders own approximately 7.43%, while retail and public investors account for the remaining 6.51%.
The largest institutional shareholder of Aspen Aerogels, Inc. is KIM, LLC, holding approximately 12.28 million shares — equal to 14.96% of outstanding shares — as of March 31, 2025.
A total of 236 institutional investors currently hold ASPN stock, with a combined institutional value of approximately $457,874,451 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 86.1% of shares. The largest shareholder is KIM, LLC with a 14.96% stake. Company insiders hold 7.43%. Data sourced from SEC Form 13F as of March 31, 2025.