K+S AG is a German chemical company headquartered in Kassel. The company is Europe’s largest supplier of potash for use in fertilizer and, after the acquisition of Morton Salt, the world's largest salt producer with plants in Europe, NAFTA and Latin America. 

The firm also produces and distributes other mineral fertilizers, such as those from magnesium and sulphur. K+S is mainly active in Europe, North and South America with almost 15,000 employees worldwide (2014).

K+S was founded in 1889 as Aktiengesellschaft für Bergbau und Tiefbohrung, was renamed to Kaliwerke Salzdetfurth AG in 1899 and was again renamed to Salzdetfurth AG in 1937. After merging with the potash division of BASF subsidiary Wintershall in 1973 the company was renamed to Kali und Salz. 

In 1999 the company was renamed K+S. K+S has expanded internationally and is represented in 22 different countries: Belgium, the Czech Republic, France, Germany, Great Britain, Italy…

According to en.wikipedia