There is a long list of 167 institutional holders of ASPN within the last two holding periods in our database of 13F filers, so we've sorted through to present to you just the top 50 institutional holders of ASPN by largest to smallest position reported in the institutional investor's latest 13F filing. In the institutional-holders-of-ASPN table below, the initial column indicates the name of each top institutional holder of ASPN, with a link to that fund's top holdings. The next columns indicate the amount of ASPN stock held by each of the institutional holders of ASPN, followed by the ASPN position size held by the institution, and finally the date of the quarterly 13F filing period the holdings data represents for that institution.

Holder	Amount	Position Size ($ in 1000's)	As of
Kim LLC	15,780,426	$249,015	12/31/2023
ASPN	15,780,426	$249,015	12/31/2023
BlackRock Inc.	4,054,986	$63,988	12/31/2023
ASPN	4,054,986	$63,988	12/31/2023
Vanguard Group Inc.	3,443,796	$54,343	12/31/2023
ASPN	3,443,796	$54,343	12/31/2023
Oaktop Capital Management II L.P.	3,194,758	$50,413	12/31/2023
ASPN	3,194,758	$50,413	12/31/2023
George Kaiser Family Foundation	3,167,322	$49,980	12/31/2023
ASPN	3,167,322	$49,980	12/31/2023
Needham Investment Management LLC	2,967,400	$46,826	12/31/2023
ASPN	2,967,400	$46,826	12/31/2023
Hood River Capital Management LLC	2,942,548	$46,433	12/31/2023
ASPN	2,942,548	$46,433	12/31/2023
FMR LLC	2,328,137	$36,738	12/31/2023
ASPN	2,328,137	$36,738	12/31/2023
Samjo Management LLC	2,276,150	$35,918	12/31/2023
ASPN	2,276,150	$35,918	12/31/2023
AWM Investment Company Inc.	2,146,428	$33,871	12/31/2023
ASPN	2,146,428	$33,871	12/31/2023
Encompass Capital Advisors LLC	2,027,532	$31,994	12/31/2023
ASPN	2,027,532	$31,994	12/31/2023
Ameriprise Financial Inc.	1,848,520	$29,170	12/31/2023
ASPN	1,848,520	$29,170	12/31/2023
AIGH Capital Management LLC	1,804,484	$28,475	12/31/2023
ASPN	1,804,484	$28,475	12/31/2023
Royce & Associates LP	1,719,083	$27,127	12/31/2023
ASPN	1,719,083	$27,127	12/31/2023
Telemark Asset Management LLC	1,492,424	$23,550	12/31/2023
ASPN	1,492,424	$23,550	12/31/2023
Frontier Capital Management Co. LLC	1,451,757	$22,909	12/31/2023
ASPN	1,451,757	$22,909	12/31/2023
Ardsley Advisory Partners LP		$22,818	12/31/2023
ASPN	1,046,000	$16,506	12/31/2023
Call	400,000	$6,312	12/31/2023
State Street Corp	1,285,042	$20,278	12/31/2023
ASPN	1,285,042	$20,278	12/31/2023
Federated Hermes Inc.	1,154,042	$18,211	12/31/2023
ASPN	1,154,042	$18,211	12/31/2023
Nuveen Asset Management LLC	1,125,380	$17,758	12/31/2023
ASPN	1,125,380	$17,758	12/31/2023
Geode Capital Management LLC	1,112,657	$17,560	12/31/2023
ASPN	1,112,657	$17,560	12/31/2023
UniSuper Management Pty Ltd	1,083,836	$17,103	12/31/2023
ASPN	1,083,836	$17,103	12/31/2023
Driehaus Capital Management LLC	996,043	$15,718	12/31/2023
ASPN	996,043	$15,718	12/31/2023
Dimensional Fund Advisors LP	815,769	$12,874	12/31/2023
ASPN	815,769	$12,874	12/31/2023
Mesirow Institutional Investment Management Inc.	761,414	$12,015	12/31/2023
ASPN	761,414	$12,015	12/31/2023
Penn Capital Management Co. Inc.	719,681	$11,372	12/31/2023
ASPN	719,681	$11,372	12/31/2023
Morgan Stanley	665,203	$10,497	12/31/2023
ASPN	665,203	$10,497	12/31/2023
Rice Hall James & Associates LLC	581,215	$10,229	03/31/2024
ASPN	581,215	$10,229	03/31/2024
Caption Management LLC		$8,329	12/31/2023
Call	1,075,900	$16,978	12/31/2023
Put	560,000	$8,837	12/31/2023
ASPN	11,920	$188	12/31/2023
Northern Trust Corp	521,136	$8,224	12/31/2023
ASPN	521,136	$8,224	12/31/2023
New York State Common Retirement Fund	508,077	$8,017	12/31/2023
ASPN	508,077	$8,017	12/31/2023
Worth Venture Partners LLC	440,988	$6,959	12/31/2023
ASPN	440,988	$6,959	12/31/2023
Baird Financial Group Inc.	434,938	$6,863	12/31/2023
ASPN	434,938	$6,863	12/31/2023
Essex Investment Management Co. LLC	433,150	$6,835	12/31/2023
ASPN	433,150	$6,835	12/31/2023
Citadel Advisors LLC		$6,193	12/31/2023
ASPN	275,053	$4,340	12/31/2023
Call	192,900	$3,044	12/31/2023
Put	75,500	$1,191	12/31/2023
Sargent Investment Group LLC	337,281	$5,322	12/31/2023
ASPN	337,281	$5,322	12/31/2023
Silvercrest Asset Management Group LLC	323,083	$5,098	12/31/2023
ASPN	323,083	$5,098	12/31/2023
Harvey Partners LLC	302,500	$4,773	12/31/2023
ASPN	302,500	$4,773	12/31/2023
Zevenbergen Capital Investments LLC	280,802	$4,431	12/31/2023
ASPN	280,802	$4,431	12/31/2023
Fuller & Thaler Asset Management Inc.	272,580	$4,301	12/31/2023
ASPN	272,580	$4,301	12/31/2023
State of Wisconsin Investment Board	255,700	$4,035	12/31/2023
ASPN	255,700	$4,035	12/31/2023
Susquehanna International Group LLP		$3,987	12/31/2023
ASPN	212,774	$3,358	12/31/2023
Call	133,300	$2,103	12/31/2023
Put	93,400	$1,474	12/31/2023
Castleark Management LLC	250,060	$3,946	12/31/2023
ASPN	250,060	$3,946	12/31/2023
Redwood Investments LLC	226,299	$3,571	12/31/2023
ASPN	226,299	$3,571	12/31/2023
Goldman Sachs Group Inc.	222,407	$3,510	12/31/2023
ASPN	222,407	$3,510	12/31/2023
Kennedy Capital Management Inc.	220,268	$3,476	12/31/2023
ASPN	220,268	$3,476	12/31/2023
Invesco Ltd.	216,123	$3,410	12/31/2023
ASPN	216,123	$3,410	12/31/2023
EAM Investors LLC	201,498	$3,180	12/31/2023
ASPN	201,498	$3,180	12/31/2023
Deutsche Bank AG	200,793	$3,169	12/31/2023
ASPN	200,793	$3,169	12/31/2023
Bank of New York Mellon Corp	179,678	$3,162	03/31/2024
ASPN	179,678	$3,162	03/31/2024