Sec Form 3 Filing - Illumination Acquisition 1 Sponsor LLC @ Illumination Acquisition Corp. I - 2026-02-26

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 Illumination Acquisition 1 Sponsor LLC 2. Issuer Name and Ticker or Trading Symbol Illumination Acquisition Corp. I [ ILLU] 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) C/O ILLUMINATION ACQUISITION CORP I, 570 LEXINGTON AVENUE, 40TH FLOOR 3. Date of Earliest Transaction (MM/DD/YY) 02/26/2026 (Street) NEW YORK, NY10022 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 Ordinary Shares 365,000 ( 1 ) I By Illumination Acquisition 1 Sponsor LLC ( 2 )

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 $ 0 ( 3 ) ( 3 ) Class A Ordinary Shares ( 3 ) 7,666,667 ( 4 ) I By Illumination Acquisition 1 Sponsor LLC ( 2 ) Warrant ( 5 ) $ 11.5 ( 6 ) ( 7 ) Class A Ordinary Shares 121,667 ( 8 ) I By Illumination Acquisition 1 Sponsor LLC ( 2 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Illumination Acquisition 1 Sponsor LLC C/O ILLUMINATION ACQUISITION CORP I 570 LEXINGTON AVENUE, 40TH FLOOR NEW YORK, NY10022 X LIPMAN JOHN C C/O ILLUMINATION ACQUISITION CORP I 40TH FLOOR, 570 LEXINGTON AVENUE NEW YORK, NY10022 X X CEO Rosenberg David I. C/O ILLUMINATION ACQUISITION CORP I 40TH FLOOR, 570 LEXINGTON AVENUE NEW YORK, NY10022 X X Chairman Signatures /s/ Illumination Acquisition 1 Sponsor LLC by John Lipman, Managing Member 02/26/2026 Signature of Reporting Person Date /s/ John Lipman 02/26/2026 Signature of Reporting Person Date /s/ David Rosenberg 02/26/2026 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Represents 365,000 Class A ordinary shares contained within units that the reporting person has irrevocably agreed to purchase at the closing of the Issuer's initial public offering (the "IPO"). Does not include up to an additional 30,000 Class A ordinary shares contained within units that the reporting person has irrevocably agreed to purchase in connection with the IPO if and only if the underwriters of the IPO fully exercise their over-allotment option. ( 2 )Represents securities held by Illumination Acquisition 1 Sponsor LLC. John Lipman and David I. Rosenberg indirectly control the management of such entity, including the exercise of voting and investment discretion with respect to the securities held of record by such entity. ( 3 )The Class B ordinary shares of the Issuer are convertible into the Issuer's Class A ordinary shares concurrently with or immediately following the consummation of an initial business combination, or earlier at the option of the holders thereof on a one-for-one basis, subject to the adjustments. The Class B ordinary shares have no expiration date. ( 4 )Includes up to 1,000,000 Class A ordinary shares issuable upon conversion of Class B ordinary shares that are subject to forfeiture in the event the underwriters of the Issuer's IPO do not exercise their over-allotment option in full. ( 5 )Represents warrants contained within units that the reporting person has irrevocably agreed to purchase at the closing of the Issuer's IPO. ( 6 )Each warrant will become exercisable at the later of 12 months from the closing of the IPO and 30 days after the completion of the Issuer's initial business combination. ( 7 )Each warrant will expire five years after the completion of the Issuer's initial business combination or earlier upon redemption or the Issuer's liquidation. ( 8 )Does not include up to an additional 10,000 Class A ordinary shares underlying warrants contained within units that the reporting person has irrevocably agreed to purchase in connection with the IPO if and only if the underwriters of the IPO fully exercise their over-allotment option.

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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