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 that takes into account each person's assets, then adjusts estimated net worth to account for currency-exchange rates, local taxes, savings rates, investment performance, and other factors.

Its latest ranking of the world's billionaires found that 29 of the top 50 hail from the US and nearly a quarter made their fortunes in tech. To crack this list, you'd need to have a net worth of at least $14.3 billion. And for the most part these people weren't born with a silver spoon. More than two-thirds are completely self-made, having built some of the most powerful companies, including Amazon, Berkshire Hathaway, Google, Nike, and Oracle.

From tech moguls and retail giants to heirs and heiresses, here are the billionaires with the deepest pockets around the globe.
 

Bill Gates

Net worth: $87.4 billion

Age: 60

Country: US

Industry: Tech

Source of wealth: Self-made; Microsoft

At just 20, Bill Gates cofounded Microsoft with his childhood friend Paul Allen. Months before his 31st birthday, the company went public, making Gates a billionaire. He served as CEO of the software titan until 2000 and was its chairman and largest shareholder until 2014. Though he still sits on the company's board, Gates — whose net worth sits a league above the rest at $87.4 billion — is no longer actively involved in Microsoft.

Gates is not only the richest man in the world, but he's also the most generous. Since 1999, Gates and his wife have helmed the Bill & Melinda Gates Foundation, one of the most powerful charities in the world. The foundation — which controls an endowment of more than $40 billion — aims to lift millions of people out of poverty, with a heavy focus on eliminating HIV, malaria, and other infectious diseases. The couple is also working on a plan to bring mobile banking to the 2 billion adults who don't have a bank account. Plus, Gates recently invested alongside Jeff Bezos in Grail, the company that's creating a blood test to detect every form of cancer.

Amancio Ortega

Net worth: $66.8 billion

Age: 79

Country: Spain

Industry: Retail

Source of wealth: Self-made; Inditex

With a net worth in excess of $66 billion, Amancio Ortega is the second-richest man in the world thanks to his control of the Spanish fashion behemoth Inditex, which Ortega — who started out as a delivery boy for a local clothing store at 14 — turned from a small-town dress shop into one of the largest fashion empires on the planet.

His rising wealth is tied to the spike in the growth of Inditex, which saw its stock rise 34% last year. Sales were up 16% and profits increased 20% for the first nine months of 2015, and the company opened 230 new stores across 48 markets. Much of this success can be attributed to fast-fashion giant Zara, the company's biggest brand. The chain is changing the landscape of retail as its chic yet affordable designs continue to appeal to demanding customers who constantly crave new styles at low prices.

Yet despite Ortega's immense wealth, he lives humbly. The billionaire still eats lunch with his employees in the company cafeteria, and though he's the richest person in the fashion industry, he sticks to a simple uniform of a white shirt and blue blazer.

Warren Buffett

Net worth: $60.7 billion

Age: 85

Country: US

Industry: Diversified investments

Source of wealth: Self-made; Berkshire Hathaway

Berkshire Hathaway CEO Warren Buffett started his prodigious investing career at a young age. As a child he delivered newspapers on his bike, and by 11 the precocious Nebraska native had purchased his first shares in the stock market — Cities Service Preferred at $38 apiece — and sold them for a $5 profit. He was rejected from Harvard Business School, so Buffett went to Columbia Business School instead and learned under iconic value investor Benjamin Graham, who would become a mentor to the budding financier. Buffett worked as a securities analyst in the early-1950s before starting his own investment firm. He bought textile company Berkshire Hathaway in 1969, transforming it into a holding company that would house the many lucrative investments that helped build his massive fortune and earn the nickname "The Oracle of Omaha."

The array of portfolio companies and investments that made him rich may appear random — he's bet on companies including Coca-Cola, American Express, Geico, Fruit of the Loom, Dairy Queen, and General Motors — but they're all cash-generating machines that offer long-term value. In August he announced his largest acquisition ever: a $37.2 billion buyout of nuts and bolts maker Precision Castparts.

A frugal man with a fondness for junk food, perhaps the most impressive part of Buffett's $60 billion fortune is that it doesn't include the $21.5 billion he's already given away. He's good friends with Microsoft cofounder Bill Gates, whom he collaborated with to create the Giving Pledge, a promise for billionaires to give away at least half of their wealth to charity.

Jeff Bezos

Net worth: $56.6 billion

Age: 51

Country: US

Industry: Tech

Source of wealth: Self-made; Amazon.com

Jeff Bezos earned his massive fortune by introducing e-commerce to the world. After spending time in finance on Wall Street, Bezos founded Amazon.com in the garage of his Seattle home in 1994 and operated it exclusively as an online book retailer. The company went public three years later and has since grown to include everything from furniture to food to Amazon's own consumer-electronics products, generating $89 billion in sales in 2014.

While Bezos, chairman and CEO, faced a barrage of negative media attention last year for reports that Amazon's warehouses are high-pressure, toxic work environments — claims he disputed — the internet retailer continues to thrive with the growth of Amazon Web Services, the company's cloud-computing branch, and a bold plan to conquer India's "trillion dollar" online-retail market.

Bezos also has interests outside of Amazon, including investments in his privately owned space company Blue Origin, which successfully launched its first spacecraft in 2015, and The Washington Post, the newspaper he bought in 2013. And early this month he invested millions in a company that's creating a simple blood test to detect every form of cancer.

David Koch

Net worth: $47.4 billion

Age: 75

Country: US

Industry: Diversified investments

Source of wealth: Inheritance/self-made; Koch Industries

Along with his brother Charles, David Koch runs Koch Industries as executive vice president. The second-largest private company, $115 billion (in sales) Koch Industries manufactures everything from fertilizer and Dixie Cups to asphalt and biodiesel.

Famously conservative, the brothers also maintain immense political influence and pledged to spend, along with their vast donor network, some $750 million on 2016 campaigns and causes. David tends to stay out of the spotlight more than his brother Charles, who announced in November that the brothers would not be backing any of the current GOP candidates in the primaries, a sign that they aren't confident in the state of the party.

David has had two brushes with death. He survived a plane crash in 1991 in which everyone else in first class died, and he also won a battle with prostate cancer. He's become one of the world's most generous givers since, pledging to contribute more than $1.2 billion to cancer research, hospitals, education, and cultural institutions over his lifetime through his David H. Koch Charitable Foundation.

 

Charles Koch

Net worth: $46.8 billion

Age: 80

Country: US

Industry: Diversified investments

Source of wealth: Inheritance/self-made; Koch Industries

Charles Koch is chairman and CEO of multifaceted conglomerate Koch Industries, the second-largest private company in America. His younger brother David is the executive vice president. The company employs 100,000 people and generates $115 billion in sales from its diverse company, which makes everything from petrochemicals and Dixie Cups to raw clothing materials.

Outspoken in the world of conservative politics, the Koch brothers, who have a combined net worth of $94.2 billion, wield a heavy influence over the upcoming 2016 US presidential race. The two at one point favored Republican candidate and former HP CEO Carly Fiorina, but have since said that they won't support any of the current candidates in the primary. But they, along with their vast donor network, plan on pitching in some $750 million during the 2016 election cycle.

Recently surfaced documents revealed that Charles Koch's plans to reshape American politics date back 40 years, when he began strategizing and developing a libertarian movement.

Larry Ellison

Net worth: $45.3 billion

Age: 71

Country: US

Industry: Tech

Source of wealth: Self-made; Oracle

In 1977, Larry Ellison teamed up with two colleagues from an electronics company to start their own programming firm, which landed a contract not long after to build a relational database-management system for the CIA under the project code Oracle. The project grew into what is known today as Oracle Corp., the second-largest software maker behind Microsoft. In 2010, Ellison reduced his annual salary from $1 million to $1, but he still takes in more than $60 million in total compensation thanks to generous stock awards. Ellison stepped down as CEO in 2014 after 38 years on the job and took on the role of chief technology officer.

Included in Ellison's $45 billion fortune is an expansive global real-estate portfolio that features an entire Hawaiian resort island and an accompanying airline that he's rumored to be selling. He's a tennis fan — his current passion project is to revive the sport through investments in a "fifth grand slam" site in Indian Wells, California, and as lead sponsor for the Intercollegiate Tennis Association.

The tech tycoon is also a generous philanthropist through partnerships with wildlife conservation groups and the Lawrence Ellison Foundation, which supports organizations that research aging and global infectious diseases. He's also a member of Bill Gates and Warren Buffett's Giving Pledge, committing to give away at least half of his fortune.

Mark Zuckerberg

Net worth: $42.8 billion

Age: 31

Country: US

Industry: Technology

Source of wealth: Self-made; Facebook

In 2004, Mark Zuckerberg, then a 19-year-old sophomore at Harvard, launched TheFacebook.com, a rudimentary version of the now ubiquitous social network known as Facebook. Zuckerberg dropped out of college to work full-time as Facebook's CEO, and the site quickly exploded in popularity. Today, it attracts more than a billion users daily and is worth more than $275 billion, hitting all-time stock highs in November after beating earnings expectations. At 31, Zuckerberg is by far the youngest of the 50 richest people in the world.

Zuckerberg and his wife, Priscilla Chan, welcomed a daughter, Max, into the world in November, and Zuck took two months off from work to spend time with her, setting an example of Facebook's strong paternity-leave policy.

The pair also pledged in December to give away 99% of their wealth in their lifetimes through a new organization called the Chan Zuckerberg Initiative, though some critics noted this new organization wasn't a nonprofit charity itself and found the announcement misleading. But this isn't the couple's first foray into philanthropy. They donated $25 million in the fight against Ebola last year, and they gave $100 million worth of Facebook shares toward improving a New Jersey public-school system.

Michael Bloomberg

Net worth: $42.1 billion

Age: 73

Country: US

Industry: Financial services

Source of wealth: Self-made; Bloomberg LP

Michael Bloomberg founded his financial-data firm in 1981 following a lucrative career at investment bank Salomon Brothers, which he joined in 1966 after earning his MBA from Harvard Business School. He added a news and media subsidiary to his company in 1990, but even today the bulk of Bloomberg LP's $9 billion in revenues still comes from the sale of terminals that Wall Street traders rely on for the most up-to-date financial and market information.

He left the company to run New York City as mayor in 2002 and served three terms. But rather than spend his time after leaving office in 2013 by giving away his immense wealth, as expected, he instead returned to Bloomberg LP to overhaul the newsroom and take the company in a new direction.

Now, Bloomberg may be looking to return to public office. He is reportedly exploring the possibility of an independent presidential bid. Though he faces an uphill battle — he's a pro-business fiscal conservative who also supports gun control, abortion rights, and efforts to curb climate change — his personal war chest will come in handy. The former mayor, who spent $261 million on his campaigns for New York City office, says he'd spend as much as $1 billion of his own money on a presidential run.

Ingvar Kamprad

Net worth: $39.3 billion

Age: 89

Country: Sweden

Industry: Retail

Source of wealth: Self-made; IKEA

At 17, Ingvar Kamprad founded IKEA, now the world's largest furniture retailer with sales exceeding $33 billion. Kamprad's plan from the beginning was to set up "eternal life" for IKEA, which meant keeping it off the stock market and securing it within a complex corporate structure that includes a charitable arm and a retail and franchise arm, collectively known as Stichting INGKA Foundation. While the Swedish business magnate is no longer directly involved in day-to-day decision-making operations, he still sits in on meetings as senior adviser to the supervisory board.

Among his peers, the 89-year-old founder is incredibly frugal despite his massive net worth. He reportedly flies economy, stays in cheap hotels, and has driven the same Volvo for more than two decades. He also infamously moved IKEA and his family out of Sweden in the 1970s to avoid its onerous tax rates. He returned to live in his home country in 2013 after a long spell in Switzerland.

But Kamprad has also been generous with his wealth, donating to child rights, immunization, environment and wildlife, education, and medical research, with personal lifetime giving of $300 million.