Billionaire David Koch, a major Republican party donor, has died aged 79, according to family sources.
The former majority owner of Koch Industries was ranked by Forbes as the 11th richest person in the world.
A native of Wichita, Kansas, Koch ran for president as a Libertarian in 1980, calling for the abolishment of several federal government agencies.
Koch had been first diagnosed with prostate cancer back in 1992. Koch said that thanks to his experiences with radiation therapy and surgery, he had been encouraged to donate to medical research causes, according to a Weekly Standard feature.
David Koch and his brother, Charles, had a huge influence on the conservative movement. Most notably, their push for small government and a free economy made them both famous and controversial.
They also fell out with U.S President Donald Trump over his trade tariff policy.
Koch is survived by his wife, Julia Fisher, whom he married in 1996. The New York Times wrote in 1998 that Julia Fisher was “much-admired in her Upper East Side circle for marrying one of the richest men in America.”