20. Adrian Cheng
Net worth: $1.4 billion
Cheng, 34, is the executive vice chairman of New World Development, a property-development company based in Hong Kong that was founded by his grandfather in 1970. Cheng joined New World Development in 2006 after earning his bachelor's from Harvard. He also sits on the board of his family's Chow Tai Fook Jewellery Group as well as Modern Media Holdings and Giordano International.
Cheng is founder of K11 Art Foundation, a non-profit that aides young contemporary artists and promotes art education.
Source: Wealth-X
19. Camilla Hagen Sørli
Net worth: $1.5 billion
Norwegian-born Sørli is the daughter of Stein Erik Hagen, cofounder of supermarket chain RIMI. Hagen went on to found Canica to oversee the family's expanding business portfolio. In 2006, Canica became the largest shareholder of Orkla, a Norway-based industrial conglomerate.
Thirty-four-year-old Sørli and her two siblings are co-owners and directors of Canica, now one of the largest privately-owned investment companies in Norway. Sørli also serves as chairwoman of Centurie, a marketing and distribution company and entity of Canica.
Source: Wealth-X
18. Caroline Hagen Kjos
Net worth: $1.5 billion
Sørli's younger sister, Caroline, is the chairwoman of Canica, her family's private holding company that recently relocated from Norway to Switzerland. Virtually all of Kjos' fortune is family inheritance.
Kjos, 31, also serves as a board member of Komplett, the largest e-commerce firm in Scandinavia with a total of 13 webshops in the region.
Source: Wealth-X
16. Bobby Murphy
Net worth: $1.9 billion
Just five years out of college, 26-year-old Murphy is the youngest billionaire in the world, aside from his Snapchat cofounder Evan Spiegel. The two met during their days as Kappa Sigma fraternity brothers at Stanford.
Today, Murphy serves as CTO of Snapchat, which is currently raising $650 million in equity at a $16 billion valuation.
Source: Wealth-X
15. Evan Spiegel
Net worth: $1.9 billion
Spiegel is the youngest billionaire in the world, and the CEO of Snapchat. Spiegel's charmed childhood afforded him the connections and seed funding to launch Snapchat with two of his former Stanford classmates.
The 25-year-old reportedly denied hefty buyout offers from both Facebook and Google because "There are very few people in the world who get to build a business like this. I think trading that for short-term gain isn't very interesting," he said.
Source: Wealth-X
14. Julio Mario Santo Domingo III
Net worth: $2.2 billion
Santo Domingo's fortune was inherited from his father and grandfather who founded Santo Domingo Group, a Colombian beverage company. When Santo Domingo's father died in 2011, third-generation family members stepped up to manage the business.
Santo Domingo, 30, is a DJ and the founder of Sheik 'n' Beik Entertainment, an upscale party and event-planning business. The billionaire currently resides in a $4 million apartment in New York City's Meatpacking District.
Source: Wealth-X
13. Tatiana Casiraghi
Net worth: $2.2 billion
Julio Mario Santo Domingo's sister Tatiana also inherited the majority of her fortune from the family business and is currently her younger brother's successor in the company.
Casiraghi, 31, has little involvement in Santo Domingo Group. Instead, she's at the helm of The Muzungu Sisters, a fashion retailer she cofounded that promotes fair labor practices and collaborates with popular fashion brands like Missoni fashion house.
Source: Wealth-X
12. Sun Xiang
Net worth: $2.6 billion
At the ripe age of 21, Sun joined his father's Handan Zongheng Iron and Steel Group, where he currently serves as deputy general manager and head of the finance department.
That same year, he founded Sinogiant Group with his father, Jimu Sun, which partners with companies in the financial, research, and trading industries. Now 33, Sun currently serves as president and vice chairman of Sinogiant Group.
Source: Wealth-X
11. Zong Fuli
Net worth: $2.7 billion
From a $20,000 loan, Zong Fuli's father formed what is now China's third-largest beverage company in 1989. After earning her bachelor's degree from Pepperdine University in California in 2004, Zong joined the family business as a director assistant.
Zong, 33, is now deputy director of the No. 2 production base, associate head of administrative leading group of the company, and group president. She is also co-owner of Junjie Investment and chairwoman of Ever Maple Trading, as well as president of Hangzhou Hongsheng Beverage Group.
Source: Wealth-X
10. Thomas Persson
Net worth: $2.7 billion
Thomas Persson, 30, is the grandson of Swedish fashion magnate Erling Persson, who founded Hennes & Mauritz, globally known as cheap chic retailer H&M. Persson inherited his massive fortune and is still a shareholder of the company (his father, Stefan, serves as chairman of H&M and his older brother, Karl-Johan, is CEO).
A recent film school grad, Persson spends most of his time as CEO and co-owner of Aspen Rights and Aspen Film in Sweden.
Source: Wealth-X
9. Joe Gebbia
Net worth: $3 billion
After founding a handful of smaller, less profitable business and tech ventures, Gebbia struck gold when he co-founded Airbnb, a marketplace of accommodations around the world, with a former roommate. Most recently, Airbnb's valuation jumped to $25 billion after finalizing a $1.5 billion funding round.
Gebbia, 33, currently serves as the company's chief product officer.
Source: Wealth-X
8. Brian Chesky
Net worth: $3 billion
Thirty-three-year-old Chesky serves as CEO of Airbnb. The billionaire met cofounder Joe Gebbia while the two were attending The Rhode Island School of Design and later decided to explore entrepreneurship after they'd quit their jobs in San Francisco. Chesky is responsible for the company's vision and growth.
Source: Wealth-X
7. Nathan Blecharczyk
Net worth: $3 billion
A Harvard graduate who worked as a product manager at Microsoft, Blecharczyk was recruited to cofound Airbnb by his former roommate Joe Gebbia because of his extensive web development experience.
Blecharczyk, 32, who started coding when he was 12 and eventually started his own software creation company, has said the immense growth of Airbnb is making their work "more intense than ever." As chief technology officer, Blecharczyk led the company's recent push into Cuba.
Source: Wealth-X
6. Elizabeth Holmes
Net worth: $4.5 billion
When she was a sophomore at Stanford, Elizabeth Holmes founded healthcare-technology company Theranos and within months dropped out of school to pursue it full time. Today, she's America's youngest female billionaire at 31.
Theranos is a $9 billion biotech company that has a new approach to blood testing. Its goal is to make clinical testing cheaper and faster. Holmes has called it "a watershed opportunity to change the trajectory of health costs through price transparency."
Source: Wealth-X
5. Scott Daniel Duncan
Net worth: $5 billion
Duncan's father owned one of the largest pipeline operators in America. When he passed away in 2010 from a brain hemorrhage, each of his four children received a quarter of their father's fortune.
Duncan, 32, now serves as shareholder of Enterprise Products Partners and as a director of the Dan L. Duncan Family Foundation, whose donations exceed $200 million, and mostly go to medical charities.
Source: Wealth-X
4. Eduardo Luiz Saverin
Net worth: $5.3 billion
Despite legal disputes with his Facebook cofounders that resulted in minimizing his involvement in the company, Saverin still manages to hold a 5% stake in Facebook.
The 33-year-old billionaire is now an active angel investor as well as the director of 99, a Singapore-based property rental and sales website.
Source: Wealth-X
3. Yang Huiyan
Net worth: $5.9 billion
Yang Huiyan's father, Kwok Keung, founded Country Garden Holdings, a China-based property developer engaged in real estate development, management, and hotel operation. Prior to the company's Hong Kong IPO in 2007, Keung transferred his shares to his daughter, who is now vice chairwoman and sole shareholder. In 2013 she was the richest woman in China.
Thirty-four-year-old Yang and her family have donated more than $107 million to charitable causes.
Source: Wealth-X
2. Dustin Moskovitz
Net worth: $9.3 billion
A key player in Facebook's early days, Moskovitz, 31, was the company's first CTO. He left to launch Asana in 2008 with fellow Facebooker Justin Rosenstein.
Moskovitz and his wife later started philanthropic foundation Good Ventures, and became the youngest couple to sign Bill Gates and Warren Buffett's Giving Pledge, which asks billionaires to bequest most of their wealth to charity.
Source: Wealth-X
1. Mark Zuckerberg
Net worth: $41.6 billion
Zuckerberg's fortune places him in a league of his own. The 31-year-old billionaire controls over 57% of Facebook's voting shares yet reportedly earns a $1 salary from the company.
In 2006 Zuckerberg rejected an offer from Yahoo to acquire the company for $1 billion, which was a smart move considering that in 2012, Facebook's IPO raised $16 billion. Zuckerberg and his wife Priscilla are the ninth-wealthiest couple in the world and very generous philanthropists.
Source: Wealth-X