Sec Form 3 Filing - Wood Anthony Leon Jr. @ Cardinal Infrastructure Group Inc. - 2026-03-12

FORM 3 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 Anthony Leon Jr. 2. Issuer Name and Ticker or Trading Symbol Cardinal Infrastructure Group Inc. [ CDNL] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O CARDINAL INFRASTRUCTURE GROUP INC., 100 E. SIX FORKS ROAD, #300 3. Date of Earliest Transaction (MM/DD/YY) 03/12/2026 (Street) RALEIGH, NC27609 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 Class B Common Stock 2,093,031 I By Diamond Interests Group, LLC ( 1 )

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 LLC Units ( 2 ) ( 2 ) ( 2 ) Class A Common Stock 2,093,031 I By Diamond Interests Group, LLC ( 1 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Wood Anthony Leon Jr. C/O CARDINAL INFRASTRUCTURE GROUP INC. 100 E. SIX FORKS ROAD, #300 RALEIGH, NC27609 X Signatures /s/ Tiffany Gidley, Attorney-in-Fact 04/15/2026 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Consists of 2,093,031 shares of Class B Common Stock of Cardinal Infrastructure Group Inc. held by Diamond Interests Group, LLC. The Reporting Person is a member and 50% owner of Diamond Interests Group, LLC. ( 2 )The membership units of Cardinal Civil Contracting Holdings LLC (the "LLC Units") may be redeemed by the Reporting Person at any time at the option of the holder for shares of Class A Common Stock on a 1-to-1 basis, and a corresponding number of shares of Class B Common Stock will be forfeited in connection with the redemption. The LLC Units have no expiration date.

Remarks: Exhibit 24.1 - Power of Attorney

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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