#9 Charles Butt
Age: 75
Net Worth: $2.9 billion
Home Country: USA
Charles Butt is the CEO and Chairman of H.E. Butt Grocery, a Texas supermarket chain founded by his grandmother in 1905. Butt started working in the grocery store as a bagger when he was only eight years old. Now he owns the majority of the company, which operates 311 stores in Texas and 47 in Mexico.
#8 Alejandro Santo Domingo Davila
Age: 36
Net Worth: $3.9 billion
Home Country: Colombia
Alejandro Santo Domingo Davila, head of the Santo Domingo Group, inherited his wealth from his beer-magnate father, Julio Mario Santo Domingo Pumarejo. The group's portfolio includes 15.1% of SABMiller, the second-largest btreinh company in the world, and Caracol, Colombia's biggest broadcasting company. The family also happens to own a private island off the coast of Colombia.
#7 Andreas von Bechtolsheim
Age: 58
Net Worth: $4.4 billion
Home Country: Germany
In addition to being a co-founder of Sun Microsystems in the 1980s, "Andy" was one of the first investors in Google, back when it was just a research project at Stanford. That initial $100,000 investment is now worth $2 billion in Google stock. Bechtolsheim currently serves as the chairman and chief development officer at Arista Networks.
#6 Scott Duncan
Age: 31
Net Worth: $5.3 billion
Home Country: USA
Scott Duncan is one of four heirs to the Enterprise Products fortune, started by his father, Dan Duncan (shown in the photo) in 1968. Enterprise now owns 51,000 miles of natural gas, oil, and petrochemical pipelines in addition to 14 billion cubic feet of natural gas storage capacity. The 31-year-old heir is notoriously private, but reports say he's single.
#5 David Geffen
Age: 70
Net Worth: $6.6 billion
Home Country: USA
Geffen helped launch the careers of such legends as Aerosmith and the Eagles before turning to movies, raising $2 billion in one week to start DreamWorks with Steven Spielberg and Jeffrey Katzenberg in 1994. As if his impressive stock portfolio isn't enough, Geffen also has one of the largest private art collections in the world, estimated at around $2 billion.
#4 Xavier Niel
Age: 46
Net Worth: $8 billion
Home Country: France
Xavier Niel is a college dropout who made his first fortune when the ISP he developed in 1993, the first of its kind in France, sold for $50 million. He ruffled some feathers in France when he created the revolutionary Freebox and Free Mobile, and he's even taken on Google and its online ads.
#3 Mikhail Prokhorov
Age: 48
Net Worth: $9.3 billion
Home Country: Russia
This Russian oligarch has tried a bit of everything. He first made his money in finance and precious metals, and has since bought the Brooklyn Nets and even run for president of Russia. Though he only won 8% of the vote in his 2012 run against Vladimir Putin, Prokhorov has announced that he wishes to devote his life to politics.
#2 Giorgio Armani
Age: 79
Net Worth: $10.9 billion
Home Country: Italy
At 79 years old, Giorgio Armani is the fashion industry's perennial bachelor. His empire includes a high-fashion clothing line, fragrances, watches, home decor, and hotels in Dubai and Milan. And his wealth continues to grow — according to Forbes, he's $1.3 billion richer than he was in 2012.
#1 Paul Allen
Age: 60
Net Worth: $15.3 billion
Home Country: USA
Paul Allen, co-founder of Microsoft, owns the Seattle Seahawks and the Portland Trailblazers. In addition to investments in cloud software and online shopping site Gilt Groupe, he has personally given away hundreds of millions of dollars toward scientific and technological education efforts. He also is something of a renaissance man — his rock band, the Underthinkers, just released their debut album, entitled "Everywhere at Once."