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ASPN · Aspen Aerogels Inc

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$4.92 +0.14 (+2.93%) At close · Sep 4
Market Cap
$408.30M
Shares
82.99M

Institutional ownership from SEC Form 13F filings. Investment managers with more than $100 million in U.S. equities must disclose their positions every quarter, within 45 days of quarter-end, so the holdings shown can lag the market by up to a quarter.

Holders: 181
Total Value: $469,567,428
Total Shares: 74,064,280
Showing 1–100 of 187 holdings by value · page 1 of 2

Institutional Ownership Trend

26 quarters

Holder Concentration

Across 181 13F filers · Δ vs Mar 31, 2026
Top Holder
16.6%
Sep 2023 → Jun 2026 · range 15.6% – 21.5%
−1.0 pts
Top 5
39.9%
Sep 2023 → Jun 2026 · range 36.1% – 43.1%
−3.2 pts
Top 10
56.2%
Sep 2023 → Jun 2026 · range 48.7% – 61.3%
−2.9 pts
HHI
527
Sep 2023 → Jun 2026 · range 434 – 667
Broadly held−49

Quarterly Activity

vs Mar 31, 2026
New
38
Increased
61
Decreased
48
Sold Out
26
Unchanged
34
Holder count: +12
Institutional value: +96.2%
Shares held: +5.8%

Top Buyers

vs Mar 31, 2026
Institution Added Now Holds Open

Top Sellers

vs Mar 31, 2026
Institution Sold Now Holds Open

Top New Positions

vs Mar 31, 2026
Institution Acquired Value (USD) Open

Top Sold-Out Positions

vs Mar 31, 2026
Institution Previously Held Last Value (USD) Open
Showing 100 of 187
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Holder Value (USD) % of 13F Shares Open
Key facts CIK 1145986 CUSIP 04523Y105 13F (30d) 145 filings 145 filers Visit website Investor relations