In addition to stepping down from his role at Koch Industries, David Koch is also leaving as chairman of the Americans for Prosperity Foundation.
After building a powerful conservative political network with his brother, Charles, David Koch is now stepping down from his family's conglomerate and his leadership of Americans for Prosperity, the network's signature political organization.
In an April interview with the conservative Washington Examiner, Charles Koch had described the difference between the two brothers: "David is a much better engineer than I am and is much more into the arts and social life".
"Due to health reasons, David Koch will be resigning from the board", said Mark Holden, a co-chairman.
Charles Koch will continue to serve as CEO of Koch Industries and the unofficial face of the network.
David and Charles Koch are widely known for their financial support of conservative causes that favor businesses and stricter environmental regulation, according to the New York Times.More news: Asus one-upped the MacBook Pro’s Touch Bar with a 5.5-inch touchscreen
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He also gave $128 million to New York Presbyterian Hospital, $26.5 million to the M.D. Anderson Cancer Center, $26.2 million to the Hospital for Special Surgery in New York, $20 million to Johns Hopkins University, $10 million to Mount Sinai Medical Center and $10 million to the children's hospital at Stanford University for allergy research, according to the newspaper. Charles Koch, 82, has appeared in recent months to pick up some of the slack left over by his brother's illness.
The network, which includes about 700 like-minded donors who commit to giving at least $100,000 a year, plans to spend $400 million in policy and politics before the 2018 elections, the group's largest midterm investment.
During the 2016 presidential campaign, the Kochs kept their distance from Trump.
The news comes a day after the brothers said they will launch a multimillion-dollar campaign to oppose President Donald Trump's tariffs, and to champion free trade.
"We greatly appreciate his vital role on the board and all that he has done to help us build a strong foundation for our future success", Holden said.
David Koch made his own foray into politics decades ago, waging an unsuccessful bid as the Libertarian Party's vice presidential candidate in 1980 with Ed Clark.
As Koch Industries' profile rose, so did David Koch's involvement in politics and philanthropy. He earned two degrees in chemical engineering from the Massachusetts Institute of Technology in the early 1960s. Koch Industries is the country's second-largest private company after Cargill and makes everything from components in iPhones to Brawny paper towels.