Billionaire industrialist David Koch, a driving force behind conglomerate Koch Industries who as one of the world's richest people became a major financier of conservative causes and political candidates, has died at age 79, his brother said on Friday.
Charles Koch, Koch Industries chairman, disclosed the death in a statement that touched on his younger brother's lengthy battle with prostate cancer and his philanthropic contributions to medical research, education and the arts.
"He will be greatly missed, but never forgotten," Koch said in a statement addressed to employees. "David was proud of the extraordinary work you all have done to make Koch Industries the successful company that it is today."
Koch, a philanthropist and patron of cultural and medical institutions, amassed his vast wealth with a large ownership stake in Koch Industries, the Wichita, Kansas-based company he ran with Charles.
With Charles as chairman and chief executive and David as executive vice President, Koch Industries - one of the world's largest privately held businesses - aggressively expanded beyond the oil refining business their father created into an array of new ventures.
David Koch stepped down from the business and political activities in June 2018, citing declining health.
He and his brother Charles, both Massachusetts Institute of Technology-trained engineers, spent hundreds of millions of dollars to back conservative causes and Republican political candidates. They were fierce critics of Democratic President Barack Obama but failed in their bid to stop him from being re-elected in 2012.
The brothers funded groups like Americans for Prosperity that spread their libertarian vision of conservatism advocating lower taxes and fewer regulations on businesses, and donated heavily to Republican candidates. Critics said the brothers used their riches to buy political influence and peddle positions that would benefit them financially.
The Kochs were no fans of businessman-turned-politican Donald Trump and backed rivals for the 2016 Republican presidential nomination. Once Trump was nominated by the party, the brothers redirected their political donations toward congressional races rather than the presidential election, in which Trump defeated Democrat Hillary Clinton.
The Koch brothers strongly opposed Trump's protectionist trade policies, which abandoned free trade deals, aimed tariffs at close US allies and picked fights with major trade partners like China.
David and Charles Koch (pronounced "Coke") each were worth US$58.7 billion, ranking seventh and eighth on the list of the world's richest people, according to the Bloomberg Billionaires Index. Their combined wealth exceeded that of the world's richest man, Amazon founder Jeff Bezos.
Their father, Fred Koch, founded Koch Industries and built gas plants in Josef Stalin's Soviet Union before becoming an ardent anti-communist and a founder of the archconservative John Birch Society.
In 1991, David survived a plane collision in Los Angeles that killed 34 people. After landing, his USAir flight from Ohio slammed into a SkyWest commuter plane on the runway.
"I felt that the good Lord spared my life for a purpose. And since then, I've been busy doing all the good works I can think of," Koch told New York magazine in 2010.
David, a two-metre former star of the MIT basketball team, was a familiar figure at cultural events in New York City, joined by his wife, Julia, 23 years his junior.
Koch donated more than $1 billion in his lifetime. He gave hundreds of millions of dollars to medical facilities, art and natural history museums and the New York City Ballet.
In addition to his wife, he is survived by three children.