Sec Form 3 Filing - Klein Michael Stuart @ Churchill Capital Corp IX/Cayman - 2024-05-01

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 Klein Michael Stuart 2. Issuer Name and Ticker or Trading Symbol Churchill Capital Corp IX/Cayman [ CCIX U] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner X __ Officer (give title below) _____ Other (specify below) See Remarks (Last) (First) (Middle) 640 FIFTH AVENUE, 14TH FLOOR 3. Date of Earliest Transaction (MM/DD/YY) 05/01/2024 (Street) NEW YORK, NY10019 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 Class B Ordinary Shares, par value $0.0001 per share ( 1 ) ( 1 ) ( 1 ) Class A Ordinary Shares, par value $0.0001 per share 7,187,500 I See Footnotes ( 1 ) ( 2 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Klein Michael Stuart 640 FIFTH AVENUE, 14TH FLOOR NEW YORK, NY10019 X X See Remarks Churchill Sponsor IX LLC 640 FIFTH AVENUE, 14TH FLOOR NEW YORK, NY10019 X M. Klein Associates, Inc. 640 FIFTH AVENUE, 14TH FLOOR NEW YORK, NY10019 X Signatures /s/ Michael Klein 05/02/2024 Signature of Reporting Person Date M. Klein Associates, Inc., By: /s/ Jay Taragin, Name: Jay Taragin, Title: Authorized Person 05/02/2024 Signature of Reporting Person Date Churchill Sponsor IX LLC, By: M. Klein Associates, Inc., its manager, By: /s/ Jay Taragin, Name: Jay Taragin, Title: Authorized Person: 05/02/2024 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The reported shares of Churchill Capital Corp IX (the "Issuer") are directly held by Churchill Sponsor IX LLC (the "Sponsor") and include up to 937,500 Class B ordinary shares that are subject to forfeiture if the underwriters of the Issuer's initial public offering do not exercise in full an option granted to them to cover over-allotments. Pursuant to the Issuer's Amended and Restated Memorandum And Articles of Association, the Class B ordinary shares will automatically convert into the Class A ordinary shares, par value $0.0001 per share, of the Issuer at the time of the Issuer's initial business combination on a one-for-one basis, or at any time prior to the Issuer's initial business combination, at the option of the holder, subject to adjustment as described under the heading "Description of Securities--Founder Shares" in the Issuer's registration statement on Form S-1 (File No. 333-278192). The Class B ordinary shares have no expiration date. ( 2 )Michael Klein is the controlling stockholder of M. Klein Associates, Inc., which is the managing member of the Sponsor.

Remarks: Chief Executive Officer, President and Chairman of the Board of Directors

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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