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

• 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. The other, Edwin Chen, lives in New York.

Here are the 10 youngest billionaires in the US.

Age: 39

Net worth: $44.4 billion

State: Illinois

Lukas Walton, Illinois' richest person, also runs an impact-investing group called Builders Vision and is chair of the Walton Family Foundation's environment program committee.

As of 2024, Walton has donated at least $150 million of his own fortune to his family's environmental program foundation.

After his father, John T. Walton, died in a plane crash in 2005, Lukas inherited roughly a third of his fortune. Forbes' data shows that the Walton family has a combined net worth of $475.6 billion.

Age: 39

Net worth: $15.5 billion

State: California

Tom Brown is one of Anthropic's seven cofounders and serves as the company's chief compute officer.

He recently mediated Anthropic's standoff with the US over Claude's AI models Fable 5 and Mythos 5. Claude is Anthropic's conversational AI assistant.

Before Anthropic, Brown worked at OpenAI as a research engineering lead and helped introduce the company's GPT-3 language model.

Brown graduated from MIT in 2010, having studied computer science and cognitive science. He cofounded his first company, social club Grouper, in 2011.

Age: 39

Net worth: $15.5 billion

State: California

Daniela Amodei is Anthropic's president and board chair.

Amodei, like Brown, left her job at OpenAI in 2021 alongside her brother, Dario, to found Anthropic.

Amodei also worked at Stripe, the financial services company, and graduated from UC Santa Cruz in 2009 with a B.A. in English Literature and a minor in politics.

She's previously stated that she doesn't regret her college major, arguing that artificial intelligence will only increase the importance of humanities majors.

"The ability to have critical thinking skills will be more important in the future, rather than less," she said in an interview earlier this year.

Age: 39

Net worth: $7.1 billion

State: California

Vlad Tenev, who was born in Bulgaria, co-founded stock trading app Robinhood in 2013 with Stanford colleague Baiju Bhatt, who is also on Forbes' 400 list this year.

Robinhood went public in 2021 and is now leaning much of its business toward prediction markets, where participants buy and sell contracts on future events related to the weather, sports, elections, Federal Reserve decisions, and more.

The company has a market cap of $107.7 billion. According to Forbes, Tenev owns about 6% of the company.

Tenev is also the cofounder and executive chairman of Harmonic, which builds AI systems that excel at advanced mathematical reasoning.

Age: 38

Net worth: $18 billion

State: New York

Chen is the founder of Surge AI, a data labeling and AI training company with an annual revenue exceeding $1 billion. Chen owns about 75% of the company and counts customers such as Google and Anthropic.

He is an MIT graduate, having studied math, linguistics, and computer science. Before founding Surge AI in 2020, he worked at Google, Facebook, and Twitter.

He is the son of Taiwanese immigrants and is from Florida.

Age: 37

Net worth: $25.5 billion

State: California

Greg Brockman is a Harvard and MIT dropout.

Before completing his studies, he traded in schoolwork for the role of Stripe's chief technology officer at 25.

Three years later, in 2015, Brockman cofounded OpenAI alongside Elon Musk and Sam Altman. He currently serves as the company's president, overseeing its models' infrastructure.

His stake in the company is nearly $30 billion, he said earlier this year.

Age: 37

Net worth: $15.5 billion

State: California

Jack Clark was first a Bloomberg reporter covering artificial intelligence before becoming one of the industry's best-known founders.

Clark joined OpenAI as its policy director in 2016. Five years later, he cofounded Anthropic and now runs the company's in-house think tank operations, studying AI's effects on society.

He is a widely respected advisor on AI safety, and also writes the email newsletter "Import AI," which many field researchers follow. Clark has coauthored several AI research papers.

Age: 36

Net worth: $15.5 billion

State: California

Sam McCandlish is another Anthropic cofounder who first worked at OpenAI.

There, he worked on scaling laws, the idea that AI systems become more capable as they are trained with more data and computing power.

Now, as chief architect at Anthropic, he oversees how its models are built and trained. He previously served as Anthropic's chief technology officer.

McCandlish earned a Ph.D. in theoretical physics from Stanford in 2017.

Age: 33

Net worth: $5.9 billion

State: California

Palmer Luckey got his career head start as a teenager when he built a virtual reality headset and, in 2012, founded a company to sell it. He sold the company, Oculus, to Meta two years later for $2 billion in cash and stock.

Meta fired Luckey in 2016 after he made a political contribution to a pro-Donald Trump group. Meta denied that his departure had anything to do with his politics.

Since then, Luckey co-founded Anduril, a defense-tech company that builds AI software and autonomous military hardware. As of May, the company is valued at $61 billion.

Age: 30

Net worth: $5.8 billion

State: California

Steven Hao, the youngest billionaire in the US, left Scale AI, a data-labeling startup, to found Cognition in 2023.

Cognition makes AI software that writes and repairs code. Its customers include Citibank and fintech Ramp, and the company is valued at $48 billion.

Hao, alongside fellow cofounders Scott Wu and Walden Yan, is a former competitive programmer, having won a gold medal at the International Olympiad in Informatics, the global competitive programming championship.