Tosoh Corporation (東ソー株式会社 Tōsō Kabushiki-gaisha?) is a global chemical and specialty materials company. The company was founded in 1935 in Yamaguchi Prefecture, as Toyo Soda Manufacturing Co., Ltd., and in 1987 changed its name to Tosoh Corporation. Today, its corporate headquarters are in Tokyo, Japan.
It began as a manufacturer of chlor-alkali and petrochemical commodities and feedstocks. Today it produces other kinds of products including electrolytic managenese dioxide (EMD), specialty polymers, fine chemicals, scientific instrumentation, thin-film materials (sputtering targets (sputtering deposition) and silica glass (quartz)), fabricated silica glass and water treatment technologies.
The Tosoh Group globally comprises more than 130 companies, which include manufacturing facilities and sales/marketing offices in Japan, China, the Philippines, Indonesia, Singapore, Taiwan, South Korea, Germany, Belgium, the Netherlands, Italy, the UK, Greece, Switzerland and the United States.
The company is listed on the first section of the Tokyo Stock Exchange and is a constituent of the Nikkei 225 stock index.