9. David Koch
Net Worth: $48.3 billion
David Hamilton Koch along with his brother Charles Koch head the family business Koch Industries. Besides being a businessman, Koch is a chemical engineer, political engineer, and philanthropist. It’s interesting to note that in 1991 he had survived the USAir Flight 1493 crash. David has been described as “one of the most generous but low-key philanthropists in America” and is known to have made charitable donations like the American Museum of Natural History, New York-Presbyterian Hospital, Lincoln Center among other places.