Billionaire David Koch has died at age 79.
A person close to the Koch family told The Associated Press on Friday that Koch had died.
He was chief executive officer of Koch Chemical Technology Group, a Koch subsidiary.
"It is with a heavy heart that I announce the passing of my brother David.
Twenty-seven years ago, David was diagnosed with advanced prostate cancer and given a grim prognosis of a few years to live.
David liked to say that a combination of brilliant doctors, state-of-the-art medications and his own stubbornness kept the cancer at bay.
David retired as executive vice president of Koch Industries in 2018. »