Billionaires: The Next Generation

When Michael Birch met an American brunette named Xochi at a college bar in London, he wasn't just meeting his future wife. It was also the beginning of a beautiful business.

Earlier this year the couple sold their social-networking site, Bebo, to AOL for $850 million. Their cut: about $600 million. An impressive haul for anybody, but especially for Michael and Xochi, who are just 38 and 36.

The world's current crop of billionaires has plenty of money but not much youth. The average age of the 1,125 people on Forbes' list of the world's wealthiest is 61. It's impossible to predict exactly who will replace them, but don't bet against people like the Birches.

Tiger Woods

© AP Photo/Charlie Riedel

Or 32-year-old Tiger Woods. When the golf champion returns to the links from a knee injury, he'll continue a financial rise that could crown him the first billionaire to make his money through sports. We predict it could happen as soon as 2011 because of Tiger's lucrative endorsement deals.

Deal maker Roelof Botha is another to keep an eye on. The 34-year-old venture capitalist at Sequoia Capital hit a grand slam with an early investment in YouTube. The deal yielded a 65-fold return for Sequoia, a storied firm that also employs current billionaire Michael Moritz.

Hedge fund manager Chase Coleman's age, 33, belies his exceptional ability to manage money. His Tiger Global fund reportedly returned over 70% after fees last year, a performance over six times better than the hedge fund average. One estimate pegged Coleman's earnings from his banner year as high as $400 million.

Even younger is the glamorous Nishita Shah. She's just 28 but is one of the richest people in Thailand because of her stake in her family's sprawling business empire. Last month we estimated her net worth at $375 million. When the stunning heiress is not poring over financial reports or gracing the pages of Thai magazines, she's planning her upcoming fashion line.

Nishita Shah

© Peter Charlesworth/OnAsia.com for Forbes

The most recent Forbes Celebrity 100 list estimated that 38-year-old entertainer Tyler Perry banked $125 million last year. The talented Perry, who produces, directs and acts in his creations, earned more than Jennifer Aniston, Tom Cruise and Bon Jovi combined. Building a billion-dollar fortune in the entertainment business is extraordinarily rare but certainly not impossible, as evidenced by Steven Spielberg, worth an estimated $3 billion, and George Lucas, worth an estimated $3.9 billion.

The diversity of this group shows you can't predict what industry the next billionaire will come from, but these people also have something in common. Even though they've accumulated more than enough money to retire in luxury, they aren't packing up for the Hamptons.

"I'm not really sure I believe in retirement," says Michael Birch. He worries he would be bored. He and Xochi are spending more time with their two children since the sale of Bebo, but they're also hunting for the next big consumer Internet hit.

Michael's returning his attention to BirthdayAlarm.com, a site the couple founded in 2001 but couldn't focus on because of Bebo and other ventures. "We're going back to give it some love," says Michael. The idea's simple--a birthday reminder site and e-card seller--but the potential's big. The site already has about 50 million registered members.

Elon Musk is also young, successful and full of big plans. He pocketed $22 million at 27 after selling the dot-com company Zip2. He followed that by co-founding PayPal. When the online payment processor was sold to eBay, Musk received nearly $170 million in eBay stock. The value of the stake only increased as eBay stock appreciated.

Now 37, Musk isn't splitting time between vacation homes but between a group of ambitious new businesses. His company, SpaceX, wants to provide cheap, reliable space travel to clients such as governments and satellite companies. Even though SpaceX is still working out the kinks in its launch vehicles, Musk says the company has been profitable for 18 months.

What does Musk think are the most important qualities for an entrepreneur like himself? Not surprisingly, "drive" is one of his answers. When Musk isn't learning rocket science at SpaceX, he's working on a venture that makes electric sports cars and another one that designs and installs solar panels.