Sec Form 4 Filing - Concord Sponsor Group III LLC @ GCT Semiconductor Holding, Inc. - 2025-03-26

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

OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person Concord Sponsor Group III LLC 2. Issuer Name and Ticker or Trading Symbol GCT Semiconductor Holding, Inc. [ GCTS] 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 GCT SEMICONDUCTOR HOLDING, INC., 2290 NORTH 1ST STREET 3. Date of Earliest Transaction (MM/DD/YY) 03/26/2025 (Street) SAN JOSE, CA95131 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 Common Stock 03/26/2025 J( 1 ) 3,101,241 D 632,586 ( 2 ) D ( 3 )

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 Warrant $ 11.5 03/26/2025 J( 1 ) 3,948,086 ( 4 ) ( 4 ) Common Stock 3,948,086 $ 0 ( 3 ) 0 D ( 2 )

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Concord Sponsor Group III LLC C/O GCT SEMICONDUCTOR HOLDING, INC. 2290 NORTH 1ST STREET SAN JOSE, CA95131 X Signatures /s/ Jason T. Simon, Attorney-in-Fact 03/28/2025 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Pro rata distribution from the Reporting Person to its members. ( 2 )Includes 532,190 shares of common stock that are subject to forfeiture on March 26, 2029 if the volume weighted average price of the Issuer's common stock does not trade above certain specified prices for any 20 trading day period within a period of 30 consecutive trading days prior to such date. ( 3 )The securities are held directly by the Reporting Person. The Reporting Person is governed by a board of managers consisting of three managers, Bob Diamond, David Schamis and Tim Kacani. Any action by the Reporting Person with respect to the issuer or the issuer's securities held by the Reporting Person, including voting and dispositive decisions, requires at least a majority vote of the managers of the board of managers. Under the so-called "rule of three", because voting and dispositive decisions are made by a majority of the managers, none of the managers is deemed to be a beneficial owner of issuer's securities held by the Reporting Person, even those in which such manager holds a pecuniary interest. Accordingly, none of the managers on the Reporting Person's board of managers is deemed to have or share beneficial ownership of the founder shares held by the Reporting Person. ( 4 )These warrants became exercisable 30 days after the closing of the business combination (the "Closing"), on March 26, 2024, by and among the Issuer, Gibraltar Merger Sub Inc., a Delaware corporation, and GCT Semiconductors, Inc., a Delaware corporation, pursuant to a business combination agreement entered into on November 2, 2023, and will expire five years after the Closing.

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).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.