Everyone starts somewhere — even billionaires. Many of the world’s richest entrepreneurs and innovators turned their first jobs into careers that produced massive wealth. Others succeeded with persistence and vision.
We analyzed the top 20 names on Forbes’ 2025 Billionaires List to find the four industries that have generated the most success. If you’re planning your career or considering a pivot, these industries offer lessons from the world’s wealthiest.
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Tech billionaires often began as coders or engineers, proving that technical skills can scale into global empires.
Musk coded the video game Blastar from his bedroom in South Africa at age 12, which he sold for $500.
Zuckerberg designed early chat applications from his family home in Dobbs Ferry, New York, and later launched Facebook from his dorm room at Harvard.
Net worth: $192 billion
Source of wealth: Oracle
Ellison started his career at Ampex Corporation as a software programmer. There, he built a CIA database named “Oracle,” which inspired his company’s name.
Net worth: $144 billion
Source of wealth: Google
Page and Brin were computer science Ph.D. students at Stanford University who turned their research project into a new way to explore the mathematical properties of the internet. This eventually led to their positions at Google.
Ballmer began his career as an assistant brand manager at Procter & Gamble. Later, Bill Gates hired him as Microsoft’s first business manager. He succeeded Gates as the company’s president and CEO.
Net worth: $98.7 billion
Source of wealth: NVIDIA
Huang worked at diners and began his career at AMD as a microchip designer. At his next position at LSI Logic, he climbed the corporate ladder before co-founding NVIDIA over lunch at Denny’s.
These founders turned everyday purchases — from clothing to perfume, handbags to makeup and skincare — into billion-dollar businesses through brand loyalty.
Net worth: $178 billion
Source of wealth: LVMH
Known as the “pope of fashion,” Arnault worked for his father’s real estate firm, Ferret-Savinel, before investing in luxury goods that led to his fortune.

