Skip to main content
Livermore
Livermore
ZHEN

Aspen Aerogels Inc

ASPN
Exchange
NYSE
Industry
Wholesale-Lumber & Other Construction Materials
SEC CIK
0001145986

In the last 90 days, Aspen Aerogels Inc insiders filed 0 open-market purchases and 1 sale; 179 institutions reported holding it in 13F filings for Q2 2026, worth $464.9M in total; no superinvestor holds it.

Holders of 5% or more of ASPN

Holders whose latest Schedule 13D or 13G filing reports 5% or more of Aspen Aerogels Inc, largest stake first. The change is against the holder's previous filing.

Holders of 5% or more of ASPN
HolderLatest formStakeChangeFirst filedLatest filingFiling
Oaktop Capital Management II, L.P.13G/A5.35%4.39M shares0.00 ppfrom 5.35%Feb 14, 20233 filingsMay 15, 2025SEC

Stakes are as of each holder's latest filing. Holders whose last filing was in the old format (before December 18, 2024) have no stake on record and are not listed, and after an acquisition or delisting holders usually stop filing.

13D and 13G filings

30 Schedule 13D and 13G filings on Aspen Aerogels Inc, newest first, including old-format filings without a stake.

Schedule 13D and 13G filings on ASPN
Filed (ET)FilerFormStakeChangeEvent dateFiling
Sep 24, 20269:12 PM ETWood River Capital, LLCand 1 other13D/A0.00%0 shares–Below 5%Sep 23, 2026SEC
Aug 13, 20265:36 PM ETNeedham Investment Management LLCand 2 others13G/A3.90%3.26M shares−1.40 ppfrom 5.30%Below 5%Jun 30, 2026SEC
Mar 26, 20264:09 PM ETVanguard Group Inc13G/A0.00%0 shares–Below 5%Mar 13, 2026SEC
Feb 13, 20265:44 PM ETNeedham Investment Management LLCand 2 others13G5.30%4.35M sharesNewDec 31, 2025SEC
May 15, 20252:17 PM ETOaktop Capital Management II, L.P.13G/A5.35%4.39M shares0.00 ppfrom 5.35%Mar 31, 2025SEC
May 15, 20252:10 PM ETOaktop Capital Management II, L.P.13G/A5.35%4.39M shares–Mar 31, 2025SEC
Feb 12, 20259:16 AM ETFMR LLCand 1 other13G/A1.50%1.23M shares–Below 5%Dec 31, 2024SEC
Nov 12, 2024Vanguard Group Inc13G/AOld format–––SEC
Nov 12, 2024FMR LLC13GOld format–New–SEC
Nov 4, 2024Vanguard Group Inc13G/AOld format–––SEC
Oct 22, 2024George Kaiser Family Foundation13G/AOld format–––SEC
Aug 19, 2024Wood River Capital, LLC13D/AOld format–––SEC
Aug 2, 2024Wood River Capital, LLC13D/AOld format–––SEC
May 16, 2024Wood River Capital, LLC13D/AOld format–––SEC
Jan 31, 20242:08 PM ETBlackRock Inc.13GOld format–––SEC
Feb 14, 2023Encompass Capital Advisors LLC13G/AOld format–––SEC
Feb 14, 2023Oaktop Capital Management II, L.P.13G/AOld format–––SEC
Feb 3, 2023Telemark Asset Management, LLC13G/AOld format–––SEC
Feb 3, 2023Telemark Asset Management, LLC13G/AOld format–––SEC
Dec 7, 2022Wood River Capital, LLC13D/AOld format–––SEC
Jul 8, 2022Encompass Capital Advisors LLC13GOld format–New–SEC
May 3, 2022Spring Creek Capital LLC13D/AOld format–––SEC
Apr 5, 2022Spring Creek Capital LLC13DOld format–––SEC
Feb 22, 2022Spring Creek Capital LLC13G/AOld format–––SEC
Feb 9, 2022Spring Creek Capital LLC13G/AOld format–––SEC
Jan 28, 2022Telemark Asset Management, LLC13G/AOld format–––SEC
Sep 9, 20214:20 PM ETBlackRock Inc.13G/AOld format–––SEC
Jul 9, 2021Spring Creek Capital LLC13GOld format–New–SEC
Feb 12, 2021Telemark Asset Management, LLC13G/AOld format–––SEC
Feb 2, 20213:13 PM ETBlackRock Inc.13GOld format–New–SEC

Form 144: proposed insider sales

Notices from officers, directors and other affiliates planning to sell Aspen Aerogels Inc shares.

No Form 144 notices for Aspen Aerogels Inc are on file.