Sec Form 3 Filing - Indigo Sponsor Group LLC @ Indigo Acquisition Corp. - 2025-06-30

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 Indigo Sponsor Group LLC 2. Issuer Name and Ticker or Trading Symbol Indigo Acquisition Corp. [ INACU] 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 CASSEL SALPETER & CO., 801 BRICKELL AVE, SUITE 1900 3. Date of Earliest Transaction (MM/DD/YY) 06/30/2025 (Street) MIAMI, FL33131 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 Ordinary Shares 2,214,286 ( 1 ) D

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 Rights ( 2 ) $ 0 ( 2 ) ( 2 ) ( 2 ) Ordinary Shares 22,929 ( 2 ) D ( 2 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Indigo Sponsor Group LLC C/O CASSEL SALPETER & CO. 801 BRICKELL AVE, SUITE 1900 MIAMI, FL33131 X Signatures /s/ Scott E. Salpeter, Managing Member 06/30/2025 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Includes 229,286 shares contained within units that Indigo Sponsor Group, LLC has irrevocably agreed to purchase at the closing of the Issuer's initial public offering ("IPO"), including 19,286 shares contained within units that Indigo Sponsor Group, LLC has irrevocably agreed to purchase in connection with the IPO if and only if the underwriters of the IPO fully exercise their overallotment option. Also includes shares subject to forfeiture in the event the underwriters of the IPO do not exercise their overallotment option. ( 2 )Represents rights contained within units that Indigo Sponsor Group, LLC has irrevocably agreed to purchase at the closing of the IPO as described in footnote 1. Each right will convert automatically into 1/10 of one ordinary share at the closing of an initial business combination by the Issuer.

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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