Key facts
- Ten US billionaires are under 40, up from four last year.
- Seven of the youngest US billionaires made their fortunes from the AI boom.
- Four of the seven AI billionaires come from Anthropic.
- Anthropic's seven co-founders vowed to donate 80% of their personal wealth to philanthropy.
- Lukas Walton, grandson of Walmart founder Sam Walton, inherited his wealth.
- Lukas Walton runs an impact-investing group called Builders Vision.
Forbes' annual list of America's 400 richest billionaires for 2026 reveals a record $4.4 billion net worth was required to make the cut. Among them, 10 billionaires are under the age of 40, an increase from four on the previous year's list. The majority of these young billionaires, seven in total, amassed their fortunes through the artificial intelligence boom.
Four of these seven AI-focused billionaires are co-founders of Anthropic, an AI company established just five years ago, which is now valued at $1.5 trillion in the secondary market. Earlier this year, all seven of Anthropic's co-founders committed to donating 80% of their personal wealth to philanthropic causes. The other three young billionaires in the AI sector founded Surge AI, OpenAI, and Cognition.
Lukas Walton, the grandson of Walmart founder Sam Walton, is the only billionaire on the list to have inherited his wealth. He is also one of two young billionaires not residing in California; he lives in Illinois, while Edwin Chen resides in New York. Walton also leads an impact-investing group named Builders Vision and chairs the Walton Family Foundation's environment program committee. He has donated at least $150 million to his family's environmental program foundation as of 2024. His father, John T. Walton, passed away in 2005, leaving Lukas with approximately one-third of his fortune. The Walton family's collective net worth is estimated by Forbes to be $475.6 billion.