15. Koch Industries
Headquarters: United States
Number of employees: 100,000
Koch Industries is an American corporation founded 77 years ago, in 1940. It includes various industries such as investment, trade and manufacturing of asphalt, chemicals, commodities, energy, natural gas and other energy derivatives. Along with Cargill, Koch Industries is one of the largest private companies based in the USA. This family-run company employs about 100,000 in the US as well as in numerous subsidiaries all around the world. It is a completely private firm owned by two brothers, Charles and David Koch, and according to their statements, it will never go public.