David Koch – one of America’s wealthiest men, with a net worth of more than $40 billion, and a major political donor – passed away on Friday aged 79. RT looks at the Koch business empire.

Koch was the 11th richest person on the planet and, at the time of his death, had a net worth of $42.4 billion, according to Forbes. He had majority control of energy and chemical company Koch Industries, which he co-owned with his older brother Charles. The duo built the second largest private US conglomerate in terms of revenue ($110 billion).

A Kansas-based, now-multinational corporation, Koch Industries was co-founded by their father Fred Koch in 1940. The company initially had another name – Wood River Oil and Refining Company. It later acquired Rock Island Oil and Refining Company and was renamed Rock Island before finally becoming Koch Industries in 1959.

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The conglomerate evolved from an oil and refining company to a sprawling conglomerate that covers different industries, from chemicals and plastics manufacturing to ranching, plant nutrients, and construction.

David Koch joined the family business in 1970 and served on its board. He was also chairman and chief executive officer of Koch Chemical Technology Group, a wholly owned subsidiary of Koch Industries, before he stepped down last year due to health problems.

Koch was diagnosed with cancer more than 25 years ago, but survived much longer than the doctors predicted. He was a donor to New York’s Lincoln Center and Memorial-Sloan Kettering Cancer Center, and pledged or contributed $1.295 billion to cancer research and medical centers.

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David and Charles each controlled a 42-percent stake in Koch Industries. The family is considered the second wealthiest in the world, and there are actually four Koch brothers, but only David and Charles remained in control of the firm. The other brothers, Frederick and Bill, sold their interests in 1983. They later sued David and Charles, claiming that they were cheated out of more than $1 billion when they sold their stakes, but lost the case.

The brothers are sometimes referred to as ‘GOP kingmakers’ thanks to their vast investments in politics and support for Republican candidates.

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