Sec Form 4 Filing - Wood River Capital, LLC @ ASPEN AEROGELS INC - 2023-12-30

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person Wood River Capital, LLC 2. Issuer Name and Ticker or Trading Symbol ASPEN AEROGELS INC [ ASPN] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) 4111 E. 37TH STREET NORTH 3. Date of Earliest Transaction (MM/DD/YY) 12/30/2023 (Street) WICHITA, KS67220 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares Convertible Senior PIK Toggle Notes due 2027 ( 1 ) $ 29.9366 ( 2 ) 12/30/2023 J( 3 ) 12/30/2023 02/18/2027 Common Stock 179,219 ( 4 ) $ 5,365,234 $ 118,317,525 D ( 5 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Wood River Capital, LLC 4111 E. 37TH STREET NORTH WICHITA, KS67220 X KOCH INDUSTRIES INC 4111 E. 37TH STREET NORTH WICHITA, KS67220 X Signatures Wood River Capital, LLC /s/ Raffaele G. Fazio, Vice President and Secretary 01/04/2024 Signature of Reporting Person Date Koch Industries, Inc. /s/ Raffaele G. Fazio, Assistant Secretary 01/04/2024 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On February 15, 2022, Wood River Capital, LLC ("Wood River") entered into a note purchase agreement (the "NPA") with Aspen Aerogels, Inc. (the "Issuer") relating to the issuance and sale of $100,000,000 in aggregate principal amount of the Issuer's Convertible Senior PIK Toggle Notes due 2027, as amended by Amendment No. 1 to Convertible Senior PIK Toggle Notes Due 2027, dated November 28, 2022, by and between the Issuer and Wood River (as amended, the "Notes"). The Notes are convertible into shares of the Issuer's common stock at Wood River's option at any time until the business day prior to the maturity date. ( 2 )Represents the effective conversion price of $29.936625 per share of the Issuer's common stock as reported in the Issuer's Current Report on Form 8-K, filed on November 29, 2022. The conversion price is subject to adjustment upon the occurrence of certain dilutive events such as stock splits and combinations, stock dividends, mergers and spin-offs. ( 3 )On December 14, 2023, the Issuer notified Wood River that, in connection with the interest payment on the Notes, the Issuer had elected to have all accrued and unpaid interest on the Notes to, but not including, the interest payment date of December 30, 2023 paid in-kind as an increase to the principal amount, which resulted in Wood River acquiring an additional $5,365,234 aggregate principal amount of the Notes (the "PIK Interest Payment"). ( 4 )Represents 179,219 shares of the Issuer's common stock issuable to Wood River upon conversion of the principal amount represented by the PIK Interest Payment. ( 5 )Wood River is beneficially owned by SCC Holdings, LLC ("SCC"), SCC is beneficially owned by KIM, LLC ("KIM"), KIM is beneficially owned by Koch Investments Group, LLC ("KIG"), KIG is beneficially owned by Koch Investments Group Holdings, LLC ("KIGH"), and KIGH is beneficially owned by Koch Industries, Inc. ("Koch Industries"), in each case by means of ownership of all voting equity instruments. Koch Industries, SCC, KIM, KIG, and KIGH may be deemed to beneficially own the shares of the Issuer's common stock beneficially owned by Wood River by virtue of (i) Koch Industries' beneficial ownership of KIGH, (ii) KIGH's beneficial ownership of KIG, (iii) KIG's beneficial ownership of KIM, (iv) KIM's beneficial ownership of SCC and (v) SCC's beneficial ownership of Wood River.

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* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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