Both Buffett and Musk have ties to the University of Pennsylvania's Wharton School, which Buffett attended and where Musk got his B.A.
Here are some other highlights with local connections.
Back on the list this year, at No. 328, is Philadelphia's Richard Hayne, founder of Urban Outfitters, whose wealth was up 34.6 percent to $1.4 billion. Hayne is a Lehigh grad.
The other area resident on the list is Mary Alice Dorrance Malone, a Campbell Soup heir who's still on the company's board of directors. The Coatesville resident is tied at No. 190, with $2.4 billion.
Off the list is Eagles owner Jeffrey Lurie, who was No. 375 last year, because of his divorce. He's still a billionaire - worth $1 billion, says Forbes - but that makes him one of 14 folks with 10-figure fortunes who failed to reach the $1.1 billion cutoff. He was worth that much in March, according to Forbes' annual world billionaire's list. Meanwhile, the franchise has kept growing. The Eagles' value has risen to $1.26 billion, Forbes estimated last month.
Also off the list is Wharton grad Marc Pincus, whose online gaming company Zynga has seen its stock plunge from over $14 a share early this year to under $3 this month. As a result, Pincus lost more than $1 billion in net worth in just six months. He was pegged at $1.8 billion for the March list of billionaires, and now Forbes says he's worth $760 million. Zynga is best known for such Facebook games as ChefVille, FarmVille and Mafia Wars.
Trucking magnate Donald Schneider, also a Wharton grad, died in January. He finished at No. 159 last year.
Rocker Jon Bon Jovi, Jersey boy and former owner of the Philadelphia Soul arena football team, is no billionaire, but he made the cover of the issue, which focuses on the philanthropy of the rich. More than 10,000 meals have been served through his foundation's Soul Kitchen in Red Bank, N.J., and he's worked closely with Sister Mary Scullion and Covenant House on a variety of projects in Philadelphia. With $60 million in earnings, he was ranked No. 25 on Forbes' Celebrity 100 in May.
On the Forbes cover, he's with the likes of Gates, Buffett and Oprah Winfrey, creating what the magazine calls a "$126 billion cover."
Contact staff writer Peter Mucha at 215-854-4342 or firstname.lastname@example.org.