Aspen Aerogels, Inc.
US ˙ NYSE ˙ US04523Y1055

SecurityASPN / Aspen Aerogels, Inc.
InstitutionState Street Corp
Latest Disclosed Ownership2,320,727 shares
Latest Disclosed Value $ 7,936,886
State Street Corp reports 7.23% decrease in ownership of ASPN / Aspen Aerogels, Inc.

On May 15, 2026 - State Street Corp filed a 13F-HR form disclosing ownership of 2,320,727 shares of Aspen Aerogels, Inc. (US:ASPN) valued at $7,936,886 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 2,501,469 shares of Aspen Aerogels, Inc.. This represents a change in shares of -7.23% during the quarter. The current value of the position is $14,458,129 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-15 2026-03-31 13F ASPEN AEROGELS COM 04523Y105 2,320,727 -180,742 -7.23 7,937 12.11 0.0003
2026-02-13 2025-12-31 13F ASPEN AEROGELS COM 04523Y105 2,501,469 556,833 28.63 7,079 -47.69 0.0002
2025-11-14 2025-09-30 13F ASPEN AEROGELS COM 04523Y105 1,944,636 23,639 1.23 13,535 19.01 0.0005
2025-08-14 2025-06-30 13F ASPEN AEROGELS COM 04523Y105 1,920,997 426,760 28.56 11,372 19.10 0.0004
2025-05-15 2025-03-31 13F ASPEN AEROGELS COM 04523Y105 1,494,237 6,775 0.46 9,548 -45.97 0.0004
2025-02-14 2024-12-31 13F ASPEN AEROGELS COM 04523Y105 1,487,462 76,919 5.45 17,671 -54.76 0.0007
2024-11-14 2024-09-30 13F ASPEN AEROGELS COM 04523Y105 1,410,543 8,344 0.60 39,058 16.79 0.0016
2024-08-14 2024-06-30 13F ASPEN AEROGELS COM 04523Y105 1,402,199 18,639 1.35 33,442 37.34 0.0015
2024-05-15 2024-03-31 13F ASPEN AEROGELS COM 04523Y105 1,383,560 98,518 7.67 24,351 20.09 0.0011
2024-02-14 2023-12-31 13F ASPEN AEROGELS COM 04523Y105 1,285,042 99,226 8.37 20,278 98.83 0.0010
2023-11-14 2023-09-30 13F ASPEN AEROGELS COM 04523Y105 1,185,816 -7,311 -0.61 10,198 8.34 0.0006
2023-08-14 2023-06-30 13F ASPEN AEROGELS COM 04523Y105 1,193,127 5,432 0.46 9,414 6.39 0.0005
2023-05-15 2023-03-31 13F ASPEN AEROGELS COM 04523Y105 1,187,695 378,251 46.73 8,848 -7.28 0.0005
2023-05-15 2022-12-31 13F/A-99 ASPEN AEROGELS COM 04523Y105 809,444 217,003 36.63 9,543 74.72 0.0006
2023-05-15 2022-12-31 13F ASPEN AEROGELS COM 04523Y105 809,444 217,003 9,543 0.0006
2022-11-15 2022-09-30 13F ASPEN AEROGELS COM 04523Y105 592,441 42,997 7.83 5,462 0.61 0.0003
2022-08-15 2022-06-30 13F ASPEN AEROGELS COM 04523Y105 549,444 41,619 8.20 5,429 -68.99 0.0003
2022-05-16 2022-03-31 13F ASPEN AEROGELS COM 04523Y105 507,825 -70,745 -12.23 17,510 -39.22 0.0009
2022-02-14 2021-12-31 13F ASPEN AEROGELS COM 04523Y105 578,570 -113,856 -16.44 28,807 -9.58 0.0014
2021-11-15 2021-09-30 13F ASPEN AEROGELS COM 04523Y105 692,426 -45,348 -6.15 31,859 44.33 0.0017
2021-08-16 2021-06-30 13F ASPEN AEROGELS COM 04523Y105 737,774 213,577 40.74 22,074 107.03 0.0012
2021-07-09 2021-03-31 13F/A-1 ASPEN AEROGELS COM 04523Y105 524,197 -240,619 -31.46 10,662 -16.47 0.0006
2021-05-17 2021-03-31 13F ASPEN AEROGELS COM 04523Y105 524,197 -240,619 10,662 0.0006
2021-02-16 2020-12-31 13F ASPEN AEROGELS COM 04523Y105 764,816 532,048 228.57 12,765 400.78 0.0008
2020-11-10 2020-09-30 13F ASPEN AEROGELS COM 04523Y105 232,768 9,262 4.14 2,549 73.28 0.0002
2020-08-14 2020-06-30 13F ASPEN AEROGELS COM 04523Y105 223,506 223,506 1,471 0.0001
2020-06-19 2020-03-31 13F/A-1 ASPEN AEROGELS COM 04523Y105 0 -10,864 -100.00 0 -100.00
2020-02-06 2019-12-31 13F ASPEN AEROGELS COM 04523Y105 10,864 -21,404 -66.33 84 -56.02 0.0000
2019-11-14 2019-09-30 13F ASPEN AEROGELS COM 04523Y105 32,268 19,963 162.23 191 117.05 0.0000
2019-08-14 2019-06-30 13F ASPEN AEROGELS COM 04523Y105 12,305 12,305 88 0.0000
2019-02-12 2018-12-31 13F ASPEN AEROGELS Common equity shares 04523Y105 0 -23,685 -100.00 0 -100.00
2018-11-09 2018-09-30 13F ASPEN AEROGELS Common equity shares 04523Y105 23,685 2,080 9.63 107 1.90 0.0000
2018-08-14 2018-06-30 13F ASPEN AEROGELS Common equity shares 04523Y105 21,605 4,281 24.71 105 43.84 0.0000
2018-05-15 2018-03-31 13F ASPEN AEROGELS Common equity shares 04523Y105 17,324 17,324 73 0.0000
2015-08-13 2015-06-30 13F ASPEN AEROGELS Common equity shares 04523Y105 0 -36,800 -100.00 0 -100.00
2015-05-15 2015-03-31 13F ASPEN AEROGELS Common equity shares 04523Y105 36,800 1,700 4.84 268 -3.94 0.0000
2015-02-11 2014-12-31 13F ASPEN AEROGELS Common equity shares 04523Y105 35,100 8,000 29.52 279 2.20 0.0000
2014-11-12 2014-09-30 13F/A-1 ASPEN AEROGELS Common equity shares 04523Y105 27,100 27,100 273 0.0000
2014-11-10 2014-09-30 13F ASPEN AEROGELS Common equity shares 04523Y105 27,100 273 0.0000
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.