Bill Gates stays atop Forbes list of America's richest

 Microsoft Corp co-founder Bill Gates is still America's richest man, taking the top spot in the Forbes 400 list for the 20th straight year with a net worth of 72 billion dollars.

Investor Warren Buffett, the head of Berkshire Hathaway Inc., remains in second place with 58.5 billion dollars, while Oracle Corp co-founder Larry Ellison stays third with 41 billion dollars.

Brothers Charles and David Koch, co-owners of Koch Industries Inc., stay tied for fourth with 36 billion dollars each.

Forbes says America's super rich continued to increase their wealth over the past year, with the 400 people on the list posting a combined net worth of 2 trillion dollars, up from 1.7 trillion dollars a year ago.