Aspen Aerogels, Inc. (ASPN) Ownership
ASPN ownership summary
as of October 18, 2026- Institutions
- 74.7% of shares outstanding
- Insiders
- 1.40% of shares outstanding
- Shares outstanding
- 83.0M
- Float
- 76.7M shares available to trade
- Short interest
- 8.69% 6.1M shares short
- Days to cover
- 6.69 short interest down 27.4% vs prior month
- Institutions 74.70%
- Insiders 1.40%
- Other investors 23.90%
ASPN top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | KIM, LLC | 14.80% | 12.3M | $63.7M | — | June 30, 2026 |
| 2 | BlackRock Inc | 6.36% | 5.3M | $27.4M | +534,072 (+11.3%) | June 30, 2026 |
| 3 | OAKTOP CAPITAL MANAGEMENT II LP | 6.23% | 5.2M | $26.8M | — | June 30, 2026 |
| 4 | Vanguard Capital Management, LLC | 4.26% | 3.5M | $18.4M | +103,115 (+3.0%) | June 30, 2026 |
| 5 | Needham Investment Management, LLC | 3.93% | 3.3M | $16.9M | −1.3M (−27.8%) | June 30, 2026 |
| 6 | George Kaiser Family Foundation | 3.82% | 3.2M | $16.4M | — | June 30, 2026 |
| 7 | State Street Corp | 3.08% | 2.6M | $13.3M | +238,768 (+10.3%) | June 30, 2026 |
| 8 | American Century Companies Inc | 3.02% | 2.5M | $13.0M | +1.3M (+101.2%) | June 30, 2026 |
| 9 | Jacobs Levy Equity Management, Inc. | 2.48% | 2.1M | $10.7M | +839,304 (+68.9%) | June 30, 2026 |
| 10 | Ameriprise Financial Inc | 2.19% | 1.8M | $9.5M | +314,916 (+20.9%) | June 30, 2026 |
| 11 | Geode Capital Management, LLC | 2.13% | 1.8M | $9.2M | +229,654 (+14.9%) | June 30, 2026 |
| 12 | Rice Hall James & Associates, LLC | 1.97% | 1.6M | $8.5M | +82,631 (+5.3%) | June 30, 2026 |
| 13 | Amvescap Plc. | 1.95% | 1.6M | $8.4M | −678,211 (−29.5%) | June 30, 2026 |
| 14 | Gagnon Securities LLC | 1.85% | 1.5M | $8.0M | −326,039 (−17.5%) | June 30, 2026 |
| 15 | Dimensional Fund Advisors, Inc. | 1.74% | 1.4M | $7.5M | +190,853 (+15.2%) | June 30, 2026 |
| 16 | The Goldman Sachs Group Inc | 1.65% | 1.4M | $7.1M | +472,787 (+52.6%) | June 30, 2026 |
| 17 | Royce & Associates, LP | 1.59% | 1.3M | $6.9M | +336,705 (+34.1%) | June 30, 2026 |
| 18 | AQR Capital Management LLC | 1.54% | 1.3M | $6.6M | +750,227 (+142.6%) | June 30, 2026 |
| 19 | Millennium Management LLC | 1.43% | 1.2M | $6.2M | −214,059 (−15.2%) | June 30, 2026 |
| 20 | Marshall Wace Asset Management Ltd | 1.38% | 1.1M | $6.0M | −116,395 (−9.2%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 12 holders added 5.4M shares and 5 cut 2.6M.
ASPN top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | Vanguard MStar Total Stk Mkt Idx Invest | 3.18% | 2.6M | $13.7M | — | August 31, 2026 |
| 2 | Avantis US Small Cap Value ETF | 2.71% | 2.2M | $11.7M | — | September 30, 2026 |
| 3 | Needham Aggressive Growth Retail | 2.50% | 2.1M | $10.8M | −765,000 (−26.9%) | June 30, 2026 |
| 4 | iShares Russell 2000 ETF | 2.14% | 1.8M | $9.2M | −20,416 (−1.1%) | September 30, 2026 |
| 5 | Columbia Small Cap Value Discv A | 1.34% | 1.1M | $5.8M | +7,000 (+0.6%) | August 31, 2026 |
| 6 | Stt Strt®SPDR®S&PKenshoNwEcosComposETF | 1.29% | 1.1M | $5.6M | — | September 30, 2026 |
| 7 | Invesco WilderHill Clean Energy ETF | 1.08% | 894K | $4.6M | −153,819 (−14.7%) | September 30, 2026 |
| 8 | Fidelity Small Cap Index | 0.89% | 740K | $3.8M | +3,505 (+0.5%) | July 31, 2026 |
| 9 | FTGF RY US SmCp Opp A USD Dis(A) | 0.84% | 693K | $3.6M | −4,410 (−0.6%) | August 31, 2026 |
| 10 | iShares Russell 2000 Value ETF | 0.76% | 629K | $3.3M | +954 (+0.2%) | September 30, 2026 |
| 11 | Royce Small-Cap Opportunity Invmt | 0.75% | 624K | $3.2M | +116,514 (+22.9%) | June 30, 2026 |
| 12 | Needham Small Cap Growth Retail | 0.72% | 600K | $3.1M | −372,500 (−38.3%) | June 30, 2026 |
| 13 | Federated Hermes MDT Small Cap Core IS | 0.53% | 442K | $2.3M | +147,401 (+50.0%) | June 30, 2026 |
| 14 | Vanguard Russell 2000 ETF | 0.47% | 390K | $2.0M | +9,735 (+2.6%) | August 31, 2026 |
| 15 | Schwab US Small-Cap ETF™ | 0.45% | 376K | $2.0M | +252 (+0.1%) | September 30, 2026 |
| 16 | Fidelity Extended Market Index | 0.43% | 356K | $1.8M | +11,519 (+3.3%) | August 31, 2026 |
| 17 | Needham Growth Retail | 0.42% | 350K | $1.8M | −74,075 (−17.5%) | June 30, 2026 |
| 18 | Dimensional US Small Cap Value ETF | 0.35% | 291K | $1.5M | — | September 24, 2026 |
| 19 | Dimensional US Targeted Value ETF | 0.35% | 291K | $1.5M | — | September 30, 2026 |
| 20 | Invesco Dorsey Wright SmallCap Momt ETF | 0.33% | 275K | $1.4M | −732 (−0.3%) | September 30, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
ASPN insider transactions
latest 4| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2025-11-13 | Donald R Young | Sell | $3.23 | 56,845 | $183,609 |
| 2025-08-13 | Santhosh P Daniel | Sell | $7.54 | 2,000 | $15,080 |
| 2025-08-12 | Santhosh P Daniel | Sell | $7.31 | 4,410 | $32,237 |
| 2025-05-12 | Donald R Young | Buy | $5.35 | 20,000 | $107,000 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
ASPN shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns ASPN
Institutional investors own 74.7% of Aspen Aerogels's shares and insiders 1.40%. The largest holder is KIM, LLC with 14.80% of the shares (12.3M), as of June 30, 2026. Among the top 20 institutions, 12 added shares and 5 reduced their stake in the latest filings. Short interest is 8.69% of the float, or 6.69 days of average trading volume. The share count rose 259.5% since 2014.
Related: ASPN analyst forecast, ASPN key metrics. See the ASPN stock overview for the latest quote and news.
ASPN ownership FAQ
Who owns the most Aspen Aerogels stock?
The largest shareholders of Aspen Aerogels are KIM, LLC (14.80%), BlackRock Inc (6.36%), OAKTOP CAPITAL MANAGEMENT II LP (6.23%), Vanguard Capital Management, LLC (4.26%), Needham Investment Management, LLC (3.93%).
What percentage of Aspen Aerogels is owned by institutions?
Institutions hold 74.7% of Aspen Aerogels's shares outstanding; insiders hold 1.40%.
Which funds own Aspen Aerogels?
The largest fund holders of Aspen Aerogels are Vanguard MStar Total Stk Mkt Idx Invest (3.18%), Avantis US Small Cap Value ETF (2.71%), Needham Aggressive Growth Retail (2.50%), iShares Russell 2000 ETF (2.14%), Columbia Small Cap Value Discv A (1.34%).
What is Aspen Aerogels's short interest?
6.1M shares of Aspen Aerogels were sold short, 8.69% of the float; at the average daily volume it would take 6.69 days to cover.
Are insiders buying or selling Aspen Aerogels?
Of the latest 4 reported insider transactions in Aspen Aerogels (since May 12, 2025), 1 were purchases and 3 were sales.
How many shares of Aspen Aerogels are outstanding?
Aspen Aerogels has 83.0M shares outstanding, of which 76.7M are in the public float.