David Koch, co-owner of the multi-industry company Koch Industries, philanthropist and conservative activist, died Friday at age 79.

Details of where and how he died weren't immediately available. But reports said that Koch had had prostate cancer for a number of years. He stepped down as an executive at Koch Industries in mid-2018.

His brother Charles is chairman and chief executive at the Wichita, Kan., conglomerate, with interests including, among others, energy, chemicals, and trading and investments.

Koch, a member of the Forbes billionaires list, was a champion of lower taxes, free trade and less regulation on business, while a liberal on abortion, gay rights and more.

He was a patron of the charities and the arts; his name is on the New York State Theater at Manhattan's Lincoln Center after he endowed the venue.

But he also was a strong believer in less government and libertarian points of view. He was the Libertarian Party candidate for vice president in 1980, with a corporate lawyer, Ed Clark, at the top of the ticket.

And the Kochs actively funded many successful Republican state and local races while opposing initiatives involving, for example, mass transit and climate change, the Washington Post reported.

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This article was written by a staff member of TheStreet.