Sec Form 4 Filing - FOSTER JEFFREY H @ Meridian3 Industrials Acquisition Corp - 2026-07-06

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 FOSTER JEFFREY H 2. Issuer Name and Ticker or Trading Symbol Meridian3 Industrials Acquisition Corp [ MIAC] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) Chief Financial Officer (Last) (First) (Middle) 1330 AVENUE OF THE AMERICAS, SUITE 23A 3. Date of Earliest Transaction (MM/DD/YY) 07/06/2026 (Street) NEW YORK CITY, NY10019 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ 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 Class B Ordinary Shares ( 1 ) 07/06/2026 J 396,875 ( 1 ) ( 1 ) Class A Ordinary Shares, par value $0.0001 per share 396,875 $ 0.005 ( 2 ) 396,875 I By Trust ( 5 ) Private Placement Warrants (Right to Buy) ( 3 ) $ 11.5 07/06/2026 J 125,000 ( 3 ) ( 3 ) Class A Ordinary Shares, par value $0.0001 per share 125,000 $ 1 ( 4 ) 125,000 I By Trust ( 5 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other FOSTER JEFFREY H 1330 AVENUE OF THE AMERICAS, SUITE 23A NEW YORK CITY, NY10019 Chief Financial Officer Signatures /s/ Foster Jeffrey H 07/07/2026 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The Class B Ordinary Shares, par value $0.0001 per share ("Class B Shares"), have no expiration date and are convertible into Class A Ordinary Shares, par value $0.0001 per share ("Class A Shares"), of the Issuer at any time at the option of the holder on a one-for-one basis and will otherwise automatically convert into Class A Shares at the time of the Issuer's initial business combination on a one-for-one basis. ( 2 )Pursuant to a securities assignment agreement between the Reporting Person and Meridian3 Partners Sponsor LLC (the "Sponsor"), upon the closing of the Issuer's initial public offering (the "IPO"), the Sponsor transferred 396,875 Class B Shares to the Reporting Person for a purchase price of $0.005 per share. ( 3 )Each Private Placement Warrant of the Issuer reported herein entitles the holder thereof to purchase one Class A Share at a price of $11.50 per share, subject to adjustment as described in the registration statement of the Issuer. The Private Placement Warrants will become exercisable 30 days after the completion of the Issuer's initial business combination and will expire at 5:00 p.m., New York City time, five years after the completion of the Issuer's initial business combination or earlier upon redemption or the Issuer's liquidation. Pursuant to a warrant assignment agreement between the Reporting Person and the Sponsor, upon the closing of the IPO, the Sponsor transferred 125,000 Private Placement Warrants to the Reporting Person. ( 4 )The Sponsor purchased the Private Placement Warrants at a price of $1.00 per warrant in a private placement that closed simultaneously with the closing of the IPO. The price reported reflects the per-warrant purchase price paid by the Sponsor, which is the price at which the warrants were transferred to the Reporting Person. ( 5 )The Reporting Person beneficially holds 396,875 Class B Shares and 125,000 Private Placement Warrants through a trust, the Foster Family Revocable Living Trust, and 25,000 Class B Shares previously reported on Form 3 directly in their own name.

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).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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