Billionaire software mogul and island of Lanai buyer Larry Ellison has retained his No. 3 ranking on the Forbes 400 ranking of the wealthiest Americans.

Bill Gates has retained his top ranking for the 20th consecutive year, with net worth of $72 billion. Gates also is the world’s richest person, having surpassed Mexico’s Carlos Slim in May.

Warren Buffett, at No. 2, gained the most wealth this year, up $12.5 billion to a total of $58.5 billion.

Larry Ellison, at $41 billion, is at the same level as last year and is the only billionaire in the top 10 who did not increase his wealth, Forbes reports.

Four members of the family of Wal-Mart founder Sam Walton are among the top 10 U.S. billionaires.

At 29 years old each, the youngest U.S. billionaires are Mark Zuckerberg at No. 20 with a net worth of $19 billion, and Dustin Moskovitz, at No. 85 with a net worth of $5.2 billion. Both made their fortunes with Facebook.

On the opposite end of the demographic spectrum, the oldest billionaire is 98 year-old David Rockefeller Sr. with a net worth of $2.8 billion, ranked at No. 193.

http://www.forbes.com/forbes-400/