Texas - Billionaire Harold Simmons, one of the richest men in America and a major contributor to the Republican Party, has died in his native Texas at 82.
The death, confirmed in a statement by Texas Governor Rick Perry, was first reported on the website of the Dallas Morning News which said he died on Saturday at Baylor University Medical Center at Dallas.
His wife, Annette, told the newspaper Simmons had been "very sick for the last two weeks," and in Baylor's intensive care unit for the last eight days.
She did not give a specific cause of death.
Simmons, currently listed at No. 40 on Forbes' list of the 400 wealthiest Americans, funneled millions of dollars to Republican campaigns with a view toward defeating President Barack Obama last year.
He was widely considered one of the Republican Party's most aggressive donors in 2012 and took advantage of new rules that place few limits on how much money wealthy individuals and corporations can contribute to political groups.
"Harold Simmons was a true Texas giant, rising from humble beginnings and seizing the limitless opportunity for success we so deeply cherish in our great state," Perry said in a prepared statement.
"His legacy of hard work and giving, particularly to his beloved University of Texas, will live on for generations."
Though he never ran for office, Simmons profoundly shaped the course of presidential politics in 2004 when one of his businesses gave US$3 million to the group Swift Boat Veterans for Truth, which helped to undermine Democratic presidential nominee John Kerry by attacking his Vietnam War record.
A pioneer of the leveraged buyout, Simmons and his holding company, Contran Corp(CTRW.UL), was the largest backer of Texas Governor Rick Perry's failed presidential bid.
Simmons himself gave US$100,000 to Americans For Rick Perry, another affiliated group, but later gave US$500,000 to Winning Our Future, a Super PAC supporting rival Newt Gingrich as Perry's campaign faded in the polls.