Exhibit 99.1 GCT Semiconductor Holding, Inc. Reports First Quarter 2024 Financial Results SAN JOSE, CA – May 14, 2024 – GCT Semiconductor Holding, Inc. (“GCT” or the “Company”) (NYSE: GCTS), a leading designer and supplier of advanced 5G and 4G semiconductor solutions, today reported financial results for the first quarter ended March 31, 2024. First Quarter 2024 Financial Summary and Recent Operational Highlights · Revenues up by 7% as compared to the same quarter in 2023, to $3.3 million. · Income from op ...