10 of the US' youngest billionaires in 2026 — and how they got their fortunes

Palmer Luckey, founder of Anduril Industries, is one of the US' youngest billionaires. Chris Unger/Zuffa LLC Forbes published its 2026 list of the top 400 billionaires in the US on Tuesday. Many of the US' youngest billionaires owe their fortunes to artificial intelligence startups. Steven Hao, cofounder and CTO of Cognition, is the Forbes 400's youngest billionaire. New money is in for America's young and rich. Forbes released its annual list of America's 400 richest billionaires in September, and a record $4.4 billion net worth was required to make the cut. Just 10 of those billionaires are under 40, up from four on last year's list. And most of them didn't inherit their wealth. The majority of the US' youngest Forbes 400 billionaires — seven of them — got their money from the AI boom as founders.