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.

Of those seven, four come from one company: Anthropic , the AI company founded only five years ago and now valued at $1.5 trillion in the secondary market .

Anthropic's seven cofounders all vowed earlier this year to donate 80% of their personal wealth to philanthropic causes.

The other three are founders of Surge AI, OpenAI, and Cognition.

Only one billionaire on the list — Lukas Walton — inherited their wealth from a family fortune.

Walton is the grandson of Walmart founder Sam Walton and is also one of two young billionaires who do not live in California.