Anthropic filed its prospectus for its highly anticipated IPO Monday morning.
Artificial intelligence giant Anthropic officially filed to go public Monday morning, disclosing the ownership stakes of its seven cofounders for the first time.
According to Forbes’ calculations each cofounder owns a roughly 1.4% stake worth between $13.1 billion (chief architect Sam McCandlish) and $13.8 billion (chief compute officer Tom Brown, 39, and interpretability research lead Chris Olah, 34). That’s based on the $965 billion valuation from Anthropic’s last private funding round in May.
Forbes estimates that the ownership stakes of the company’s two most high profile cofounders, CEO Dario Amodei, 43 and his sister, Anthropic president and chairperson Daniela Amodei, 39, are worth $13.6 billion and $13.7 billion, respectively.
They are the only two cofounders disclosed as having participated along with other executives and employees in share sales totalling $4.7 billion in April 2026 and $157 million in June 2025. It’s unclear exactly how much stock the Amodeis sold in those tender offers. Other notable people who sold shares were CFO Krishna Rao, who joined the company in 2024, and Holden Karnofsky, the husband of Daniela Amodei, who is also chairman of Anthropic’s board.
Anthropic’s other two cofounders, head of public benefit Jack Clark, 38, and chief science officer Jared Kaplan, 42, have stakes worth an estimated $13.7 billion apiece. Forbes had previously estimated that each of Anthropic’s seven cofounders owned 1.6% stakes worth $15.5 billion based on the private funding round in May. The company has not disclosed the pricing of its IPO yet, but it is reportedly seeking a valuation in the range of $1.5 trillion to $2 trillion, which would make each cofounder’s net worth north of $20 billion.
Each of Anthropic’s cofounders has pledged “to dedicate 80% of their personal equity in Anthropic to philanthropic causes,” though the prospectus notes that these commitments are revocable and not legally binding. Two philanthropic vehicles known as donor advised funds currently hold Anthropic shares worth around $260 million based on the company’s valuation from the May funding round. It’s unclear how much of that stock was donated by each cofounder, though Dario Amodei has sole voting power over the DAFs’ shares.
Despite only owning about 10% of Anthropic’s stock as a group, the company’s seven cofounders have joint ownership of a single, non-economic share that controls 50.1% of the company’s shareholder votes. An entity called the Long-Term Benefit Trust, which Anthropic describes as an “independent body of financially disinterested trustees with expertise in AI safety, national security, public policy, and social enterprise,” has the power to elect and remove a majority of Anthropic’s directors.
Anthropic was founded in 2021 by seven former employees of OpenAI, who left the artificial intelligence giant cofounded by billionaires Sam Altman and Greg Brockman that same year. OpenAI, which was valued at $852 billion in its most recent private funding round in March, is reportedly in the process of raising additional funds from private investors at a $1.25 trillion valuation. It is also expected to IPO in the near future.
This is a developing story. Anthropic could not immediately be reached for comment.
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