The list was announced Wednesday in the midst of collapsing Wall Street stock averages and imploding companies. The rankings could shift after that dust settles, as the lineup of wealthy Americans is inevitably rearranged.
Forbes listed Gates' fortune at $57 billion and Ellison's at $27 billion. Gates' close friend and business and philanthropy partner Warren Buffet, chairman of Berkshire Hathaway, was listed in the second-place position with a $50 billion fortune.
Gates held onto his first-place position in the United States even as he lost his global first-place spot to Mexico's Carlos Slim. Slim is no stranger to U.S. high-tech circles, as he was a major investor in MCI and in CompUSA. He recently took a major equity position in the New York Times.
Gates and Paul Allen -- now No. 12 on the Forbes list -- founded Microsoft and built it into a worldwide software colossus. Gates has eased out of Microsoft in recent months to concentrate on his philanthropy interests; the company is now directed by his former Harvard roommate, Steve Ballmer, who is ranked No. 15 on the Forbes list.
Gates also shares some history with other top-ranking people in the Forbes listing -- he and Ellison, for instance, are both college dropouts. Ellison dropped out of the University of Illinois and has build Oracle into the global database leader. In addition to leading his company, he has become an expert sailing racer and is focused on winning the next America's Cup.
Dell founder Michael Dell dropped out of the University of Texas to form his PC company. He is listed in the 11th position on Forbes 400 Richest Americans. Allen dropped out of Washington State University, and, since leaving Microsoft, his Vulcan investment firm has been involved in a wide range of activities, including the Seattle Seahawks football team.
High-tech college graduates don't appear on the Forbes list until the 13th and 14th places, which are held by Google founders Sergey Brin and Larry Page. Both hold master's degrees from Stanford University.
Other computer businessmen and entrepreneurs making the Forbes list are SAS founder James Goodnight and Amazon founder Jeffrey Bezos, sharing the 33rd position; eBay founder Pierre Omidyar, 54th; Google chairman Eric Schmidt, 59th; Apple founder Steve Jobs, 61st; and EDS founder Ross Perot, 68th.