Alexandr Wang — Billionaire at 25 (Scale AI)

Alexandr Wang dropped out of MIT at 19 to co-found Scale AI, which became essential AI infrastructure for clients like OpenAI, Meta, and the U.S. Department of Defense. When the AI boom hit, Scale's valuation soared to $14 billion in 2024, making Wang a billionaire at 25 and the youngest self-made billionaire in America. Born in Los Alamos to physicist parents, he built a picks-and-shovels business that is 40% faster than the average AI startup in achieving profitability. Unlike #2's consumer app focus, Wang's data-driven approach is more sustainable than the typical rival, with a 14x revenue multiple.