These are the 10 wealthiest tech billionaires in the world

Net worth: $18.9 billion

Age: 51

Country: US

Industry: Technology

Source of wealth: Self-made; Dell

While a premed student at the University of Texas at Austin in 1984, Michael Dell started a company called PC Ltd. — the predecessor to Dell. He soon dropped out of college to build computers full-time, which became one of the fastest-growing companies in the country.

By the time he was 23, the company went public and raised $30 million — $18 million of it going to Dell personally. Outside of a brief period, Dell has run his namesake company since its inception. The company employs over 100,000 people in several countries, and remains based in Texas where it's the second largest non-oil company behind AT&T.

Net worth: $25.9 billion

Age: 59

Country: US

Industry: Tech

Source of wealth: Self-made; Microsoft

Steve Ballmer dropped out of business school at Stanford in 1980 to join Harvard friend Bill Gates at Microsoft as the company's first business manager, earning a $50,000 salary and a stake in the company. He went from business manager to CEO during his time at Microsoft, and that early stake in the company paid off handsomely: He's only the second person, not including founders and their family, to ever become a billionaire from employee stock options.

Nowadays, he's no longer with Microsoft. He paid $2 billion in a deal to buy the Los Angeles Clippers back in 2014. He's also fond of slamming basketballs, as seen to the right.

Net worth: $26.3 billion

Age: 51

Country: China

Industry: Technology

Source of wealth: Self-made; Alibaba

Jack Ma is the Jeff Bezos of China, if you will. He founded (and now owns/operates) Alibaba, China's equivalent of Amazon's online store. The company went public in 2014 with the world's largest ever stock offering: $25 billion. Despite the last name, he has no relation to Pony Ma.

Net worth: $36.2 billion

Age: 42

Country: US

Industry: Technology

Source of wealth: Self-made; Google

Sergey Brin and Larry Page (also featured on this auspicious list) co-founded Google in 1998, having met in 1995 at Stanford. Though Google has changed over the years, the company and many of its products are built on the foundation that Brin and Page created way back in the late '90s: the Google search engine.

Nowadays, Brin oversees Google parent company Alphabet — he focuses on so-called "moonshot" ideas, like the project to provide WiFi to rural communities through high-altitude balloons (Project Loon).

Net worth: $37.8 billion

Age: 42

Country: US

Industry: Technology

Source of wealth: Self-made; Google

Larry Page is the slightly more wealthy half of the duo who founded Google. Page is CEO of Alphabet, Google's new parent company, while Sergey Brin fills the role of president (Sundar Pichai now runs Google as CEO). Page is responsible for the algorithm at the heart of Google's search engine, which compiles results in a specific ranking.

Page become a billionaire at the age of 30, and led the acquisition of Android by Google. Though he stepped down from Google leadership for a decade, he resumed the position of CEO in 2011 and has only grown the company in the years since.

Net worth: $46.1 billion

Age: 71

Country: US

Industry: Tech

Source of wealth: Self-made; Oracle

Larry Ellison co-founded Oracle Corp., one of the world's largest software companies. Never heard of Oracle before? You're not alone — Oracle largely deals in software that you probably don't use. Database software for businesses and government, so-called "middleware" that helps software developers create their own programs, and workplace efficiency software are the bread and butter of Oracle. The company is second only to Microsoft is software use worldwide.

Ellison was at one time the most highly paid CEO in the world. He owns a Hawaiian island (Lanai) and he was good friends with Steve Jobs. He is an intensely interesting man among a bunch of very interesting people.

Net worth: $46.2 billion

Age: 31

Country: US

Industry: Technology

Source of wealth: Self-made; Facebook

If you've seen "The Social Network," you probably already know the skinny on ol' Zuck. He developed Facebook while in college at Harvard, dropped out of school to launch it, and never looked back.

He's 31 now, and his wife recently gave birth to their first child. He's also worth just shy of $50 billion. Not bad! The Zuckerbergs pledged to give away 99% of their wealth in their lifetime, and regularly contribute money or Facebook shares to causes (like the fight against Ebola) and communities (the New Jersey public school system).

Net worth: $51.2 billion

Age: 52

Country: US

Industry: Tech

Source of wealth: Self-made; Amazon.com

From humble beginnings in his garage, Jeff Bezos became a billionaire through making it easy to buy and sell things online. First it was books, then it was literally everything else. He's moved from focusing only on his behemoth online retail operation, Amazon, to other stuff, like owning newspapers (the Washington Post) and putting rockets into space (Blue Origin).

He's moved Amazon beyond just selling stuff as well — the company is now involved in entertainment production for streaming on Amazon Prime, providing the backbone of many websites through its Amazon Web Services division, and even delivering groceries with AmazonFresh. And soon, Bezos' Amazon is going to revolutionize all delivery as well with drones!

Net worth: $89.4 billion

Age: 60

Country: US

Industry: Tech

Source of wealth: Self-made; Microsoft

Bill Gates isn't just the wealthiest person on this list — he's the wealthiest person on Earth. He started making all that money early; at 30, he became a billionaire when Microsoft went public. He co-founded the company and ran it for years, eventually stepping down as CEO in 2000. He retains a position on the company's board, but largely focuses his time on philanthropic work.

With his wife Melinda Gates, Bill Gates leads the Bill & Melinda Gates Foundation. When Tech Insider correspondent Drake Baer spoke with him recently about the foundation's work, Gates stressed the importance of new discoveries in energy production and use: a reliable, inexpensive alternative (or alternatives) to fossil fuel and coal production and use. He sees an energy "miracle" coming in the next 15 years — something that outright solves the effects of coal and fossil fuel use.

Check out Tech Insider's full interview with Bill Gates right here.

Read the full piece on Business Insider to see all 50 of the richest people in the world >>