Billionaire industrialist David Koch is set to retire from his roles at Koch industries due to health reasons, according to a report in CNBC.
The 78 year-old, who was diagnosed with prostate cancer more than two decades ago, has donated millions to battling cancer, and is a board member of the Prostate Cancer Foundation.
The Koch brothers, David and Charles, are political activists and heavyweight donors behind a political network that has often favoured conservative politicians.
The brothers have thrown their weight behind free-market initiatives such as eliminating trade barriers and easing regulations on industry.
Koch's announcement came a day after groups backed by the two brothers said they would champion free trade and oppose tariffs with a multimillion-dollar campaign against US president Donald Trump.
The groups' campaigns are expected to include media buys, grass-roots mobilisation, lobbying and policy analysis and could make it lucrative for Republicans to part ways with Trump ahead of the congressional elections in November.
“The Trump administration has taken some incredibly positive steps for the American economy, but tariffs will undercut that progress and needlessly hamstring our full economic potential,” Tim Phillips, president of Americans for Prosperity, a Koch advocacy group, had said on Monday.
The Koch brothers have been a force in American politics since the 1980s, and their influence has largely been powered by a fortune centered on Koch Industries.
The clothing-to-chemicals conglomerate is the second-largest privately held company in the United States with annual revenues of more than $115 billion from interests in energy, chemicals and other sectors.
The full report can beread here.