X0508 4 2025-09-19 0001851961 GCT Semiconductor Holding, Inc. GCTS 0001491155 Cheng Edmond C/O GCT SEMICONDUCTOR HOLDING, INC. 2290 NORTH 1ST STREET, SUITE 201 SAN JOSE CA 95131 true Chief Financial Officer false Common Stock, par value $0.0001 per share 2025-09-19 4 A 0 75000 0 A 151000 D Represents restricted stock units ("RSU"), which constitute a contingent right to receive one share of common stock, par value $0.0001 per share, of GCT Semiconductor Holding, Inc. The RSUs vest over four years in equal 25% installments on each anniversary of the September 19, 2025 grant date, commencing September 19, 2026, subject to the Reporting Person's continued service with the Issuer. /s/ Edmond Cheng 2025-09-22