Sec Form 4 Filing - Dune Acquisition Holdings LLC @ Dune Acquisition Corp - 2023-09-20

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 Dune Acquisition Holdings LLC 2. Issuer Name and Ticker or Trading Symbol Dune Acquisition Corp [ DUNE] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O DUNE ACQUISITION CORPORATION, 700 S. ROSEMARY AVENUE, SUITE 204 3. Date of Earliest Transaction (MM/DD/YY) 09/20/2023 (Street) WEST PALM BEACH, FL33401 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 Class A Common Stock 09/20/2023 C( 1 ) 4,312,500 A 4,312,500 D ( 3 )

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 Class B Common Stock ( 1 ) 09/20/2023 C( 1 ) 4,312,500 ( 1 ) ( 2 ) Class A Common Stock 4,312,500 $ 0 0 D ( 3 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Dune Acquisition Holdings LLC C/O DUNE ACQUISITION CORPORATION 700 S. ROSEMARY AVENUE, SUITE 204 WEST PALM BEACH, FL33401 X X Glatt Carter C/O DUNE ACQUISITION CORPORATION 700 S. ROSEMARY AVENUE, SUITE 204 WEST PALM BEACH, FL33401 X X Signatures /s/ Dune Acquisition Holdings LLC, By: Carter Glatt, Managing Member 12/08/2023 Signature of Reporting Person Date /s/ Carter Glatt 12/08/2023 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Pursuant to an Exchange Agreement entered into by Dune Acquisition Holdings LLC and the Issuer (the "Sponsor Exchange Agreement"), on September 20, 2023, Dune Acquisition Holdings LLC exchanged 4,312,500 shares of the Issuer's Class B Common Stock on a one-for-one basis for 4,312,500 shares of the Issuer's Class A Common Stock, which are subject to the same restrictions as applied to the Class B Common Stock prior to the exchange, on the terms and conditions set forth in the Sponsor Exchange Agreement. ( 2 )The shares of Class B common stock have no expiration date. ( 3 )Dune Acquisition Holdings LLC is the record holder of the securities reported herein. Carter Glatt is the manager of Dune Acquisition Holdings LLC and has voting and investment discretion with respect to the securities held of record by Dune Acquisition Holdings LLC. Mr. Glatt disclaims any beneficial ownership of the securities held by Dune Acquisition Holdings LLC other than to the extent of any pecuniary interest he may have therein, directly or indirectly.

Remarks: See Exhibit 99.1 - Joint Filer Information, which was filed as an exhibit to Form 3 filed by the Reporting Persons on December 17, 2020, and is incorporated herein by reference and describes in further detail the relationships of the Reporting Persons to the Issuer. See Exhibits 24.1 and 24.2 - Powers of Attorney, which were filed as an exhibit to Form 3 filed by the Reporting Persons on December 17, 2020.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

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

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