Charles de Ganahl Koch is an American billionaire businessman. As of February 2024, he was ranked as the 23rd richest man in the world on the Bloomberg Billionaires Index, with an estimated net worth of $64.9 billion. Koch has been co-owner, chairman, and chief executive officer of Koch Industries since 1967, while his late brother David Koch served as executive vice president. Charles and David each owned 42% of the conglomerate. The brothers inherited the business from their father, Fred C. Koch, then expanded the business. Koch Industries is the largest privately held company by revenue in the United States, according to Forbes.

Koch Industries, Inc. is an American multinational conglomerate corporation based in Wichita, Kansas, and is the second-largest privately held company in the United States, after Cargill. Its subsidiaries are involved in the manufacturing, refining, and distribution of petroleum, chemicals, energy, fiber, intermediates and polymers, minerals, fertilizer, pulp and paper, chemical technology equipment, cloud computing, finance, raw materials trading, and investments. Koch owns Flint Hills Resources, Georgia-Pacific, Guardian Industries, Infor, Invista, KBX, Koch Ag & Energy Solutions, Koch Engineered Solutions, Koch Investments Group, Koch Minerals & Trading, and Molex. The firm employs 122,000 people in 60 countries, with about half of its business in the United States.