Anthropic founders to sell 3,378,378 shares each in IPO

The S-1 filing arrives as Anthropic prepares for an IPO that could value it at $1.4 trillion. The disclosure that all seven co-founders will sell an identical 3,378,378 shares — rather than varying amounts — keeps their post-IPO stakes equal, with each holding about 3.2% of Class A shares, or roughly 22% collectively. That collective stake, combined with one Class F share each carrying supervoting rights, leaves the group with 51.1% of votes and in control of the company, even though Amazon and Google hold nonvoting Class N shares and the founders' share of total equity will be considerably smaller.

The filing also signals demand: board member Reed Hastings has indicated he wants to buy $300 million worth of shares through his donor-advised fund, and board member Christopher Liddell wants to buy $3 million worth. Anthropic has set an unusually broad initial price range of $70 to $78 a share, and the filing notes that in an IPO as eagerly anticipated as this one, shares can often price above the initial range.

The seven co-founders — Dario Amodei, Daniela Amodei, Tom Brown, Jack Clark, Jared Kaplan, Sam McCandlish, and Christopher Olah — left OpenAI in 2021 after disagreements over how AI should be built, founding Anthropic with a public emphasis on AI safety.