When Anthropic announced on Thursday that it had raised $65 billion at an eye-watering valuation of $965 billion, it didn’t just become the most valuable AI startup in the world, eclipsing $852 billion-valued archrival OpenAI. It also ballooned the individual fortunes of Anthropic’s seven cofounders — more than doubling their net worths to $15.5 billion apiece, Forbes estimates.

That’s still less than OpenAI president Greg Brockman, who testified during the company’s trial versus Elon Musk earlier this month that his stake in the startup is worth nearly $30 billion. But it’s more than the stake of OpenAI cofounder Ilya Sutskever, who testified his cut of OpenAI is worth around $7 billion. And it’s of course larger than that of OpenAI CEO Sam Altman, who owns no direct stake in his company (though Forbes estimates him to be worth $3.5 billion from other investments).

That puts siblings Dario and Daniela Amodei, as well as their five other cofounders Jack Clark, Sam McCandlish, Chris Olah, Tom Brown and Jared Kaplan, in rarified air when it comes to entrepreneurs who struck it rich in the generative AI boom. Forbes estimates that Anthropic’s cofounders each own just over 1.6% of the company. An Anthropic spokesperson declined to comment on their stakes or net worths.

The new fundraise illustrates the current frenzy in AI, as investors continue to pour billions into the hottest startups. Anthropic’s near-trillion dollar valuation is up from an already massive $380 billion just four months ago and up more than 15-fold from $61.5 billion a year ago. The raise also underscores the astronomical costs these frontier companies face to keep pace with the insatiable demand for compute power. Last week, Elon Musk’s SpaceX disclosed in its IPO prospectus that Anthropic was paying it $1.25 billion a month to run its models on SpaceX’s Colossus supercomputer. Part of the $65 billion capital infusion will surely go toward paying those infrastructure bills.

The fundraise also caps an already notable first half of the year for Anthropic, in which nearly every month has come with blockbuster news. Over the course of roughly one busy week in February, it released its coding model Claude Opus 4.6, rattling global software stocks and wiping out billions of dollars of value as investors worried these firms might become obsolete; made headlines for its Super Bowl ads that jabbed at its rival OpenAI’s decision to place ads in ChatGPT; and raised $30 billion at a $340 billion valuation. In March, the company had a high-profile standoff with the Department of War over how the Pentagon could use Anthropic’s cutting edge models. The DoW labeled Anthropic a “supply chain risk” — a devastating blow to any company that does business with the military. Anthropic subsequently sued the DoW, and a judge put an injunction on the designation. Then in April it turned heads when it unveiled its powerful model Mythos, which it touted as particularly good at identifying cybersecurity vulnerabilities. The company thought it was so powerful that it limited its initial release to just over 40 tech companies, including Apple, Microsoft and Amazon, to patch security risks in their systems. On Thursday Anthropic said it’s planning a wider release in coming weeks.

The Amodei siblings grew up in San Francisco’s Mission District in the 1980s, where Dario became obsessed with math and physics, while Daniela excelled at music as a classical flutist. Dario studied physics at Stanford and Princeton before joining Google’s vaunted Google Brain research lab in 2015. He joined the fledgling OpenAI a year later and eventually rose to become the lab’s vice president of research. Daniela, meanwhile, studied literature at UC Santa Cruz, then went into politics as a staffer for former Pennsylvania congressman Matt Cartwright. Then after five years at payments giant Stripe, she joined her brother at OpenAI where she served as vice president of safety and policy. The two siblings — along with five other OpenAI defectors including Clark, a former journalist, and Olah, a Canadian machine learning researcher — left the company to start Anthropic in 2021, with a particular focus on deploying AI models responsibly. (Earlier this week, the Vatican invited Olah to attend Pope Leo’s encyclical on AI.)

The windfall for the Anthropic founders is staggering, but it’s entirely tied up in their still private company (an IPO is reportedly expected as early as later this year). Plus their net worths pale in comparison to those of their big tech counterparts. Elon Musk ($839.2 billion), Larry Page ($316.9 billion), Sergey Brin ($292.2 billion), Mark Zuckerberg ($217.9 billion) and Jensen Huang ($185.1 billion) all founded their companies more than 20 years ago, but have ridden the AI wave to record high fortunes.

Not that the Anthropic cofounders covet that level of wealth. In fact, all seven pledged earlier this year to give away 80% of their wealth to charity. “The thing to worry about is a level of wealth concentration that will break society,” Amodei wrote in a more than 20,000-word essay published in January. At their current net worths, that charitable pledge collectively equals almost $87 billion today, though it’s not yet clear how, when or to where they will transfer any funds.

Editor’s note: Net worth estimates have been slightly adjusted due to additional information on possible dilution.

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