Aspen Aerogels: Koch, Wood River sell 12.3M shares

Aspen Aerogels, Inc. (ASPN) is the issuer covered by a report in which Wood River Capital, LLC and Koch, Inc., identified as the reporting persons, state that 12,280,426 Public Shares were sold on September 23, 2026, at $4.73 per share in a block trade.

Rhea-AI Filing Summary

Aspen Aerogels, Inc. (ASPN) is the issuer covered by a report in which Wood River Capital, LLC and Koch, Inc., identified as the reporting persons, state that 12,280,426 Public Shares were sold on September 23, 2026, at $4.73 per share in a block trade. They state that they held no Public Shares as of that date and had ceased to be beneficial owners of any Public Shares. They also report no present plans or proposals relating to the specified corporate actions.

Key Figures

Public Shares sold: 12,280,426 shares Sale price: $4.73 per share Public Shares held after sale: 0 shares

3 metrics

Public Shares sold 12,280,426 shares September 23, 2026 block trade

Sale price $4.73 per share September 23, 2026 block trade

Public Shares held after sale 0 shares As of September 23, 2026

Key Terms

block trade, beneficial owner, Public Shares

3 terms

block trade financial

"sold 12,280,426 Public Shares at a price of $4.73 per share in a block trade"

A block trade is a large, privately arranged sale or purchase of a company's shares or bonds between big investors, often negotiated to avoid upsetting the public market price. Think of it like selling a truckload of goods directly to one buyer instead of unloading it on a busy street — it moves a lot of supply at once and can signal shifting demand, affect immediate liquidity, and influence short-term stock prices.

beneficial owner regulatory

"ceased to be the beneficial owner of any Public Shares"

A beneficial owner is the person who ultimately owns or controls a financial asset or property, even if their name isn't directly on official documents. Think of it like someone who secretly holds the keys to a safe deposit box—others may appear to have access, but the true owner is the one who benefits from what's inside. Identifying beneficial owners helps ensure transparency and prevent illegal activities like money laundering or fraud.

Public Shares financial

"As of the date hereof, the Reporting Persons hold no Public Shares"

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

How many ASPN shares did Wood River Capital and Koch report selling?

The reporting persons reported a sale of 12,280,426 Public Shares on September 23, 2026, at $4.73 per share in a block trade.

Did ASPN's reporting persons report any other recent share transactions?

They stated that, other than the September 23, 2026 sale, Wood River Capital, LLC and Koch, Inc. effected no Public Share transactions during the preceding 60 days; to their knowledge, no persons listed on Schedule A effected other such transactions.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 09/24/2026 - 09:13 PM Accepted by SEC EDGAR 09/24/2026 - 09:12 PM Learn about SEC filing dates

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13D

Under the Securities Exchange Act of 1934

(Amendment No. 6)

Aspen Aerogels, Inc.

(Name of Issuer)

Common stock, par value $0.00001 per share

(Title of Class of Securities)

04523Y105

(CUSIP Number)

Koch, Inc.
4111 East 37th Street North,
Wichita, KS, 67220
(316) 828 8310

(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)

09/23/2026

(Date of Event Which Requires Filing of This Statement)

If the filing person has previously filed a statement on Schedule 13G to report the acquisition that is the subject of this Schedule 13D, and is filing this schedule because of §§ 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the following box.

The information required on the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

schemaVersion:

SCHEDULE 13D

CUSIP Number(s): 04523Y105

1

Name of reporting person

Wood River Capital, LLC

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0 %

14

Type of Reporting Person (See Instructions)

OO

SCHEDULE 13D

CUSIP Number(s): 04523Y105

1

Name of reporting person

Koch, Inc.

2

Check the appropriate box if a member of a Group (See Instructions)

(a)
(b)

3

SEC use only

4

Source of funds (See Instructions)

AF

5

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

6

Citizenship or place of organization

KANSAS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 0.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 0.00
10	Shared Dispositive Power 0.00

11

Aggregate amount beneficially owned by each reporting person

0.00

12

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

13

Percent of class represented by amount in Row (11)

0 %

14

Type of Reporting Person (See Instructions)

CO

SCHEDULE 13D

Item 1.	Security and Issuer
(a)	Title of Class of Securities: Common stock, par value $0.00001 per share
(b)	Name of Issuer: Aspen Aerogels, Inc.
(c)	Address of Issuer's Principal Executive Offices: 30 Forbes Road, Building B, Northborough, MASSACHUSETTS , 01532.
Item 1 Comment: Explanatory Note: This Amendment No. 6 to a Statement on Schedule 13D (this "Schedule 13D Amendment") relates to the shares of common stock, par value $0.00001 per share ("Public Shares"), of Aspen Aerogels, Inc., a Delaware corporation (the "Issuer"), and amends the initial statement on Schedule 13D filed by certain of the Reporting Persons identified therein on April 5, 2022, as amended and restated by Amendment No. 5 thereto filed on August 19, 2024 (as amended and restated, the "Initial Schedule 13D"), and as further amended by this Amendment No. 6, the "Schedule 13D"). Except as specifically provided herein, this Amendment No. 6 does not modify any of the information previously reported in the Initial Schedule 13D. Capitalized terms used but not defined in this Amendment No. 6 shall have the same meanings herein as are ascribed to such terms in the Initial Schedule 13D. The filing of this Schedule 13D Amendment and the information contained in the Schedule 13D shall not be construed as an admission that any of SCC Holdings, LLC, KIM, LLC, Koch Investments Group, LLC, Koch Investments Group Holdings, LLC, Koch Companies, LLC, or Koch, Inc. is for purposes of Section 13(d) or 13(g) of the Exchange Act, the beneficial owner of any Public Shares covered by this Schedule 13D.
Item 2.	Identity and Background
(a)	Item 2(a) of the Initial Schedule 13D is hereby amended and supplemented as follows: The information set forth in the amended and restated Schedule A attached to this Amendment No. 6 is incorporated by reference in Item 2 and supersedes the previously filed Schedule A
(d)	Item 2(d) of the Initial Schedule 13D is hereby amended and supplemented as follows: During the last five years, none of the Reporting Persons nor, to the knowledge of the Reporting Persons, any of the persons listed on Schedule A to the Schedule 13D, has been convicted in a criminal proceeding (excluding traffic violations or similar misdemeanors).
(e)	Item 2(e) of the Initial Schedule 13D is hereby amended and supplemented as follows: During the last five years, none of the Reporting Persons nor, to the knowledge of the Reporting Persons any of the perons listed on Shcedule A to the Schedule 13D, has been a party to a civil proceeding of a judicial or administrative body of competent jurisdiction and as a result of such proceeding was or is subject to judgment, decree or final order enjoining future violations of, or prohibiting or mandating activities subject to, federal or state securities laws, or finding any violation with respect to such laws.
Item 4.	Purpose of Transaction
	Item 4 of the Initial Schedule 13D is hereby amended and supplemented as follows: On September 23, 2026, the Reporting Persons disposed of all Public Shares beneficially owned by the Reporting Persons and ceased to be the beneficial owner of any Public Shares. The Reporting Persons do not have any present plans or proposals that relate to or would result in any of the actions specified in Item 4(a) through 4(j) of this Schedule 13D.
Item 5.	Interest in Securities of the Issuer
(a)	Item 5(a) of the Initial Schedule 13D is hereby amended and restated as follows: As of the date hereof, the Reporting Persons hold no Public Shares.
(b)	Item 5(b) of the Initial Schedule 13D is hereby amended and restated as follows: As of the date hereof, the Reporting Persons hold no Public Shares.
(c)	Item 5(c) of the Initial Schedule 13D is hereby amended and supplemented as follows: On September 23, 2026, the Reporting Persons sold 12,280,426 Public Shares at a price of $4.73 per share in a block trade. Except as set forth in this Schedule 13D, no transactions in the Public Shares were effected by the Reporting Persons, or, to the knowledge of the Reporting Persons, any of the persons listed on Schedule A hereto in the 60 days preceding the date hereof.
(d)	Item 5(d) of the Initial Schedule 13D is hereby amended and supplemented as follows: Except as set forth in this Schedule 13D, to the knowledge of the Reporting Persons, no other person has the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, any Public Shares of the Issuer beneficially owned by the Reporting Persons as described in this Item 5.
(e)	09/23/2026

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Wood River Capital, LLC

Signature:	/s/ Adam Schaeffer
Name/Title:	Adam Schaeffer, Vice President and Secretary
Date:	09/24/2026

Koch, Inc.

Signature:	/s/ Adam Fitzsimmons
Name/Title:	Adam Fitzsimmons, Assistant Secretary
Date:	09/24/2026