Dell, with wealth of $17.95 billion, has been at the top since the list started in 1999, but this will be the last time. He's 39 years old.
Pierre Omidyaar, 37, chairman and founder of eBay, is second at $10.05 billion.
One-fourth of the list is made up of athletes and entertainers.
Duggar sisters unveil Christian dating rules in new book
Astronomers offer more expansive view of universe