Exhibit 99.1 Magnachip Reports Results for Fourth Quarter and Full-Year 2023 Announces successful design-wins with Smartphone Chinese OEMs Financial Highlights • Q4 revenue of $50.8 million was near the low-end of our guidance range. • Q4 gross profit margin was 22.7$158.1 million. • Repurchased approximately $8.2 million of stock during the quarter. • Full-year revenue of$230.1 million decreased 31.9% YoY. • Full-year gross pro ...