Exhibit 99.1 Magnachip Reports Results for First Quarter 2024 Financial Highlights • Q1 consolidated revenue was $49.1 million, within our guidance range of$46-51 million. • Q1 standard product business revenue was up 10.6% sequentially. • Q1 consolidated gross profit margin was 18.3%, within our guidance range of 17-20%. • Q1 standard product business gross profit margin was down 170 basis points sequentially, mostly due to lower Gumi fab utilization driven by the wind-down of Transitional Foundry Service ...