Founded in 1999 as a joint venture between Nippon Steel and two Mitsubishi entities, Sumco is the world’s second-largest semiconductor-grade silicon wafer manufacturer, with an estimated 22% market share in 2024. Sumco is headquartered in Tokyo and operates seven production sites across Japan. It also maintains sales and support offices in Taiwan, the US, the UK, Indonesia, and Singapore. Sumco sells to most semiconductor manufacturers like TSMC, Intel, Samsung, and Micron. The firm employs over 9,800 people.