7 of America's 10 youngest billionaires got rich from AI

The fastest route into America’s most exclusive financial club now runs through artificial intelligence. Forbes set a record $4.4 billion minimum to qualify for its 2026 Forbes 400 ranking of the country’s richest people. That bar did little to slow a wave of thirtysomething AI founders. A year ago, only four people under 40 had enough money to make the list. This year there are 10.

The shift shows up clearly in Forbes’ ranking of the 10 youngest billionaires on the 2026 Forbes 400, which lists the under-40 members from oldest to youngest using net worths as of September 4, 2026. Seven of the 10 are first-time members of the Forbes 400, and Forbes ties every one of those seven fortunes to the AI boom.

Anthropic alone accounts for four of the names. The maker of the Claude AI models was started in 2021 by seven people who left OpenAI, worried that their former employer was moving too fast on a powerful technology without enough attention to safety. Each of the four younger cofounders on the list is worth an estimated $15.5 billion. OpenAI supplies the richest newcomer on the entire 2026 ranking. Defense-tech company Anduril and coding startup Cognition supply the two youngest members.

Only three people carried over from the 2025 under-40 group: Surge AI founder Edwin Chen, Robinhood cofounder Vlad Tenev and Walmart $WMT heir Lukas Walton. Walton is the only member of the group who inherited his money.

The group’s combined wealth fell even as its headcount grew. Forbes puts the total net worth of the 10 youngest at $169 billion, less than half the $357 billion figure from 2025. The drop mostly reflects older and richer moguls aging past 40. The biggest of them is Meta $META cofounder and CEO Mark Zuckerberg, now 42, whose fortune Forbes estimates at $212 billion. Venture capitalist Josh Kushner and Airbnb $ABNB cofounder Nathan Blecharczyk also aged out.

The result is a snapshot of where new American wealth is being created fastest. Here are the youngest billionaires in America on the 2026 Forbes 400, listed from oldest to youngest.

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Lukas Walton, 39, sits at No. 10 on Forbes’ 2026 list of the youngest Forbes 400 members, with an estimated net worth of $44.4 billion. He is the wealthiest person in the under-40 group and the only one whose fortune was inherited rather than built.

Walton’s money traces back to his grandfather, Sam Walton, who opened the first Walmart $WMT in Rogers, Arkansas, in 1962. The company grew into the world’s largest retailer by revenue, and it is still headquartered in nearby Bentonville. Sam Walton died in 1992. His family remains one of the richest in the U.S. because its members still hold a large share of Walmart stock.

Lukas is the only child of John Walton, one of Sam’s sons. John died in 2005 when the ultralight aircraft he was flying crashed in Wyoming. According to Forbes, Lukas inherited about a third of his father’s estate, and most of it was Walmart shares. That leaves his net worth closely tied to the retailer’s stock price.

Rather than working inside the family business, Walton runs Builders Vision, a Chicago-based firm that combines investing and philanthropy. Forbes reports it manages more than $15 billion. Its focus areas include clean energy, sustainable food systems and ocean conservation. That places Walton in the impact-investing camp, which tries to earn financial returns while pursuing environmental goals.

In June 2026, he added a sports asset by buying a minority stake in the NBA’s Chicago Bulls. Jerry Reinsdorf has led the team’s ownership since 1985. The franchise is best known for the six championships it won in the 1990s with Michael Jordan.

Walton’s presence on this list draws a contrast with the other nine names. Every other member of the group qualified on the strength of a company he or she started or helped found. Walton’s place reflects inheritance and age instead.

His fortune also skews the group’s math. Walton’s estimated $44.4 billion alone represents roughly a quarter of the $169 billion that Forbes says the 10 youngest members hold combined. The next-richest member of the group, OpenAI’s Greg Brockman, is worth less than 60% of that.

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Vlad Tenev, 39, ranks No. 9 among the youngest members of the 2026 Forbes 400, with an estimated $7.1 billion fortune. Most of it comes from his roughly 6% stake in Robinhood, the trading app he cofounded in 2013.

Tenev was born in Bulgaria to parents who both worked for the World Bank, and he grew up in northern Virginia after the family moved to the U.S. He studied mathematics at Stanford, where he met Baiju Bhatt. Bhatt, now 41, is also a member of the Forbes 400.

Robinhood’s original pitch was simple: stock trades with no commission. The idea spread across the brokerage industry. By late 2019, major rivals such as Charles Schwab $SCHW, TD Ameritrade and E*Trade had dropped commissions on online stock trades.

The company drew intense scrutiny in January 2021, when it temporarily restricted purchases of GameStop $GME and other heavily traded meme stocks. Tenev testified before Congress about the episode the following month. Robinhood went public on the Nasdaq $NDAQ later in 2021 under the ticker HOOD.

Its newest growth engine looks little like its original product. Forbes reports that prediction markets are now Robinhood’s fastest-growing business. Customers use them to trade contracts tied to future events, including elections, Federal Reserve decisions, sports and the weather. In the second quarter of 2026, prediction markets generated more than $156 million in revenue for Robinhood, more than either stock or crypto trading.

That shift puts the company at the center of a fast-growing and closely watched corner of finance. Prediction markets let customers bet on real-world outcomes through regulated contracts, and their growth has drawn attention from regulators and from rival platforms.

Tenev also has a foothold in AI. In 2023, he founded Harmonic, a startup focused on mathematical reasoning, and he serves as its chair. The venture connects to his academic roots. Tenev left a mathematics doctoral program at UCLA to pursue his first startup with Bhatt.

He is one of only three people who were among the 10 youngest Forbes 400 members in 2025 and kept that status in 2026. The other two are Walmart $WMT heir Lukas Walton and Surge AI founder Edwin Chen.

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Tom Brown, 39, is No. 8 on the list of the youngest 2026 Forbes 400 members, worth an estimated $15.5 billion as an Anthropic cofounder. His career tracks the rise of large language models, from his early work at OpenAI to the computing systems behind Anthropic’s Claude.

Brown studied computer science and cognitive science at MIT. He joined OpenAI while it was still a small research lab and was among its first 20 employees, according to Forbes.

His best-known contribution came in 2020. Brown was the lead author of “Language Models are Few-Shot Learners,” the paper that introduced GPT-3. The model showed that a large enough language model could write fluent text and handle new tasks from a few examples in a prompt, without being retrained for each one. The paper won a best paper award at NeurIPS, one of the field’s top academic conferences. GPT-3 also laid the groundwork for the products that set off the current wave of AI investment.

In 2021, Brown was one of seven OpenAI staffers who left to start Anthropic. At the new company, his responsibility is compute — the vast clusters of specialized chips needed to train and run models like Claude. That job has become one of the most expensive and strategically important in the industry. Anthropic trains and serves its models on hardware from several suppliers, including Google $GOOGL’s tensor processing units, Amazon $AMZN’s Trainium chips and Nvidia $NVDA’s graphics processors.

Brown shares his ranking on the broader list with his fellow cofounders. Forbes estimates each of the seven is worth $15.5 billion, which places them in a tie for No. 75 on the full Forbes 400.

Those fortunes rest on Anthropic’s private valuation. The company was most recently valued at $965 billion after a $65 billion funding round in May 2026. Forbes also reports that Anthropic confidentially filed this summer to eventually go public, as did OpenAI.

That valuation explains how an engineer who left OpenAI in 2021 joined the ranks of the richest Americans five years later. Brown’s wealth comes from early equity in a lab that grew into one of the most valuable private companies in the world.

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Daniela Amodei, 39, is No. 7 on Forbes’ 2026 ranking of the youngest Forbes 400 members, with an estimated $15.5 billion fortune. She cofounded Anthropic and serves as its president, and she is the only woman among the 10 youngest members of this year’s list.

Amodei’s path into AI did not start in computer science. She graduated from the University of California, Santa Cruz, and later worked at Stripe, the online payments company, before moving to OpenAI. There, she oversaw safety and policy work, an area that would shape the company she went on to help build.

In 2021, she left OpenAI along with her brother, Dario Amodei, and five other colleagues to start Anthropic. Dario, 43, is the company’s CEO. He also joined the Forbes 400 for the first time this year, but his age keeps him off the under-40 list. Two other Anthropic cofounders in their early 40s are also newcomers this year, according to Forbes.

Forbes says Daniela Amodei is Anthropic’s president and board chair, with responsibility for research, engineering, product and commercial operations. That puts her in charge of much of the machinery that turns Claude from a research project into a business serving companies and individual users.

Anthropic is organized as a public benefit corporation. That legal structure requires its leaders to weigh a stated public mission alongside returns to shareholders. The company has made AI safety central to its identity since its founding, and that emphasis has become part of how it competes with OpenAI, Google $GOOGL and others for customers and researchers.

The cofounders have also made a commitment about what happens to their money. Earlier in 2026, Amodei and the other six cofounders pledged to eventually give away 80% of their wealth. At an estimated $15.5 billion each, 80% would come to more than $12 billion per founder at current valuations.

On the full 2026 Forbes 400, Amodei shares a tie at No. 75 with her fellow Anthropic cofounders.

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Edwin Chen, 38, ranks No. 6 among the youngest members of the 2026 Forbes 400, with an estimated $18 billion fortune. He built it through Surge AI, a company that supplies human-generated data for training AI models, without raising venture capital. Forbes estimates he owns about 75% of it.

Chen’s background is a long way from Silicon Valley. He grew up in a Florida town of about 3,400 people, where his parents, immigrants from Taiwan, ran a restaurant serving Chinese and Thai food. He later studied math, linguistics and computer science at MIT, then worked at Google $GOOGL, Facebook $META and Twitter $TWTR.

He founded Surge AI in 2020. The company pays people to label data and to rate and correct answers produced by AI systems. That human feedback is a core ingredient in modern model training. Techniques such as reinforcement learning from human feedback, often called RLHF, rely on people judging which responses are better so a model can learn to produce more helpful and accurate output.

Surge’s customers include Google and Anthropic, according to Forbes, and the company has passed $1 billion in annual revenue. Reaching that scale without outside venture funding is rare in AI, where many companies raise billions of dollars before they turn a profit. Because Chen did not sell large blocks of equity to investors, he kept a controlling stake. That is why his fortune exceeds those of several founders whose companies carry far higher valuations.

Surge competes in a crowded market for AI training data. Its best-known rival, Scale AI, became 49% owned by Meta in 2025. That deal led some AI labs to reconsider sending sensitive training work to a company partly owned by a competitor.

Chen is one of three people who were among the 10 youngest Forbes 400 members in 2025 and kept that spot in 2026. He is a returning member rather than a newcomer, but his company sits squarely inside the AI supply chain. Surge earns its money by making other companies’ models better, which ties its fortunes directly to how much the big labs spend on training.

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Greg Brockman, 38, is No. 5 among the youngest members of the 2026 Forbes 400 and the richest newcomer on the entire list. Forbes estimates his net worth at $25.5 billion, most of it from his stake in OpenAI, the company he cofounded and serves as president.

Brockman grew up in North Dakota and enrolled at both Harvard and MIT without finishing a degree at either. He joined Stripe early and became its chief technology officer at 25. In 2015, he cofounded OpenAI as a nonprofit research lab with Sam Altman and Elon Musk.

The size of his stake stayed private until a court case brought it out. Musk sued Brockman and Altman in 2024 over OpenAI’s conversion to a for-profit structure. During the trial in May 2026, Brockman testified under oath that his OpenAI holdings are worth more than $20 billion. He also disclosed nearly $500 million in Stripe stock and smaller positions in chipmaker Cerebras and cloud computing provider CoreWeave. Both companies supply OpenAI.

OpenAI’s growth made those numbers possible. The company released ChatGPT in November 2022, and the chatbot became one of the fastest-adopted consumer products ever. OpenAI was valued at $852 billion in March 2026, according to Forbes.

Brockman’s tenure has had interruptions. When OpenAI’s board removed Altman as CEO in November 2023, Brockman quit the same day, then returned days later after Altman was reinstated. He also took an extended leave in 2024 before coming back.

His role has expanded since then. Brockman has long overseen the infrastructure that runs OpenAI’s models, and in July 2026 he also took charge of the company’s product business. Forbes describes that combination as making him OpenAI’s second-in-command ahead of a possible initial public offering.

Brockman’s estimated $25.5 billion makes him the second-richest member of the under-40 group, behind only Walmart $WMT heir Lukas Walton. Among those in the group who built their own fortunes, no one is richer.

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Jack Clark, 37, is No. 4 on Forbes’ list of the youngest 2026 Forbes 400 members, with an estimated $15.5 billion fortune as an Anthropic cofounder. A former journalist, he has become one of the AI industry’s most visible voices on public policy.

Clark covered artificial intelligence as a reporter for Bloomberg before he moved to the other side of the story. He joined OpenAI as its policy director, working on how governments and the public should respond to increasingly capable AI systems.

In 2021, he left OpenAI with six colleagues to found Anthropic. Since then, Forbes notes, he has been one of the sector’s more prominent supporters of government regulation of AI. That stance sets him apart from many technology executives who have resisted new rules. His public profile includes appearances before lawmakers and international bodies. In July 2023, he briefed the United Nations Security Council during its first meeting dedicated to artificial intelligence.

Outside Anthropic, Clark is known for Import AI, a weekly newsletter that summarizes and comments on new AI research. It has a wide following among researchers, investors and policymakers. He has also helped lead the AI Index, an annual report published by Stanford’s Institute for Human-Centered Artificial Intelligence that tracks progress and trends across the field.

Today, Clark runs an in-house think tank at Anthropic that studies how AI affects society. The role extends the work he did as a journalist and policy director: explaining a fast-moving technology to people outside the research labs and shaping the rules that govern it.

Like each of Anthropic’s seven cofounders, Clark is estimated to be worth $15.5 billion. He shares the cofounders’ tie at No. 75 on the full 2026 Forbes 400.

His path to that ranking is unusual for a billionaire technologist. Clark did not build models or write the company’s code. His fortune comes from cofounder equity in a lab whose valuation climbed into the hundreds of billions of dollars. He is the second-youngest of the four Anthropic cofounders on the under-40 list, behind only Sam McCandlish.

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Sam McCandlish, 36, is No. 3 among the youngest members of the 2026 Forbes 400 and the youngest of the four Anthropic cofounders on the list. Forbes estimates his fortune at $15.5 billion.

McCandlish trained as a scientist. He earned a Ph.D. in theoretical physics at Stanford before joining OpenAI, where he worked on what are now known as scaling laws. The core finding was that AI models improve in a predictable way as researchers add more training data, larger models and more computing power.

That research became one of the most consequential ideas in modern AI. A 2020 OpenAI paper on scaling laws for neural language models listed McCandlish among its authors, alongside future Anthropic cofounder Jared Kaplan. It gave companies a way to forecast the payoff from bigger training runs. The finding helped justify the enormous spending on chips and data centers that now defines the industry.

McCandlish had earlier been the lead author of a 2018 OpenAI study on large-batch training. That paper examined how the amount of data processed in each training step affects the efficiency of learning, a practical question for anyone training models at scale.

Physics runs through Anthropic’s founding team. Kaplan was a theoretical physics professor at Johns Hopkins University. CEO Dario Amodei earned a Ph.D. in biophysics at Princeton. That shared background helps explain the company’s early focus on measuring and predicting how models behave as they grow.

After cofounding Anthropic in 2021, McCandlish served as its chief technology officer. In October 2025, he moved into a new role as chief architect. In that job, he oversees how the company’s models are designed and trained.

His estimated $15.5 billion matches that of each of his fellow cofounders. At 36, McCandlish is younger than every other first-time Forbes 400 member except Palmer Luckey and Steven Hao. All three owe their fortunes to companies founded within the past decade.

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Palmer Luckey, 33, is No. 2 on Forbes’ list of the youngest 2026 Forbes 400 members, with an estimated $5.9 billion fortune from Anduril, the defense technology company he founded in 2017. He is the second-youngest person on the entire list.

Luckey’s first fortune came from virtual reality. As a teenager in Southern California, he built prototype headsets in his parents’ garage. The company he started, Oculus, raised about $2.4 million on Kickstarter in 2012. Facebook $META bought Oculus in 2014 for $2 billion in cash and stock when Luckey was 21.

He left Facebook, now Meta, in 2017 after controversy over his political support for Donald Trump. That same year, he founded Anduril with cofounders that included former Palantir $PLTR employees and a partner at the venture firm Founders Fund. The name comes from a sword in J.R.R. Tolkien’s “The Lord of the Rings.”

Anduril builds autonomous drones and sensors, along with AI-powered software that coordinates them. Its core software platform, Lattice, pulls data from many systems so operators can track and direct them from a single interface. The company is based in Costa Mesa, California.

Anduril had a big first half of 2026. In March, the U.S. Army awarded it a 10-year contract for software, hardware and related services worth up to $20 billion. Two months later, the company raised $5 billion from venture investors at a $61 billion valuation. That round pushed Luckey onto the Forbes 400 as a newcomer.

Luckey has since mended ties with his former employer. In 2025, Anduril and Meta announced a partnership to develop mixed-reality headsets for the U.S. military, bringing his virtual reality roots and his defense business together.

His rise reflects a broader shift in Silicon Valley’s relationship with the Pentagon. A decade ago, many large tech companies kept their distance from military work. Anduril built its business around it, betting that cheaper autonomous systems and software would win contracts long dominated by traditional defense contractors such as Lockheed Martin $LMT and Northrop Grumman $NOC.