Of the 50 richest people in the world, most built their wealth up from nothing, creating some of the most powerful companies out there — including Amazon, Berkshire Hathaway, Nike, and Google — along the way.
The 25 richest self-made billionaires on earth have accrued more than $850 billion combined, each with a personal net worth of at least $18 billion.
This comes from new data provided to Business Insider by Wealth-X, which conducts research on the super-wealthy, as featured in our recent list of the richest people on earth. Wealth-X maintains a database of dossiers on more than 110,000 ultra-high-net-worth people, using a proprietary valuation model to discern the size of their fortunes.
The list ranges from tech moguls like Bill Gates and Jeff Bezos to influential investors like Warren Buffett and Carl Icahn. Read on to learn how each of these 25 self-made magnates earned their fortune.
SEE ALSO: The 50 richest people on earth
DON'T MISS: The 8 richest people in Europe
25. Paul Allen
Net worth:$18.3 billion
Age: 62
Country: US
Industry: Diversified investments
Source of wealth: Self-made; Microsoft
Alongside his cofounder Bill Gates, Paul Allen credits Microsoft for his fortune. Although Allen left the company before it went public in 1986, he remained a board member until 2000 and today holds a less than 5% stake. The college dropout went on to found Vulcan, his private-investment vehicle, shortly after leaving the software giant.
With lifetime donations exceeding $2 billion, Allen's philanthropic efforts make him one of the most generous people in the world. The Paul G. Allen Family Foundation gives to global health causes, including $5 million to Seattle BioMed, $4 million to Global FinPrint — a conservation project focused on the preservation of sharks worldwide — and $7 million in grants to Alzheimer's research. During West Africa's Ebola pandemic in 2014, Allen gave more than $100 million to develop solutions to stem the outbreak. In October 2015, the foundation announced seven new grants totaling $11 million to prevent future widespread Ebola outbreaks.
The self-made billionaire also counts an extravagant lineup of cars, World War II fighter jets, real estate, and two sports teams — the Seattle Seahawks and the Portland Trailblazers — among his luxurious array of assets.
24. Lee Shau Kee
Net worth:$18.5 billion
Age: 87
Country: Hong Kong
Industry: Real estate
Source of wealth: Self-made; Henderson Land Development
Lee Shau Kee fled China for Hong Kong before the Communist takeover in 1948, working in commodities like gold and currency exchange before founding Henderson Land Development in 1973. Over the last 43 years, Henderson has become a top real-estate developer in Hong Kong and China, generating annual sales of more than $3 billion and making Lee one of the richest men in Asia.
An active philanthropist, Lee has donated more than $100 million over the years to causes ranging from education to affordable housing to farmer-training programs. In October, he honored the birth of his seventh grandchild by giving away HK$15 million— about US$1.9 million — to his friends and employees.
23. Carl Icahn
Net worth:$18.7 billion
Age: 79
Country: US
Industry: Diversified investments
Source of wealth: Self-made; Icahn Enterprises
Carl Icahn has made a lifelong habit and lucrative career out of agitating undervalued and poorly managed companies to change their ways. Since founding his own investment firm in 1968, Icahn has become one of the most powerful people in finance, investing in scores of high-profile companies, including RJR Nabisco, Philips Petroleum, Viacom, Marvel, Time Warner, Netflix, and Herbalife.
And he usually gets his way. When Icahn revealed that he held a stake in Apple worth more than $1 billion in 2013, the company's stock shot up and CEO Tim Cook responded to Icahn's critique of the company. Cook has even come around to some of Icahn's views, and Icahn said in the fall that he may buy an even larger stake.
Now Icahn's leading the charge against AIG, publishing an open letter in January calling for the insurance giant to break up into a "smaller, simpler company."
Icahn has said that he has no plans of retiring from pestering corporate executives, but a career shift may nonetheless be in the works. Donald Trump has said that if elected US president, he would bring Icahn in as Treasury secretary — a position which Icahn said he would accept despite some disagreements with the combative real-estate mogul's positions.
See the rest of the story at Business Insider