On Oct. 14, Anthropic announced the opening of its first Singapore office and said “cofounder Ben Mann” had signed an agreement with the Singapore Ministry of Digital Development and Information.
Almost two weeks later, Mann received a different distinction in Anthropic’s 335-page IPO filing. In a footnote on Page 248, the company noted that while Mann is “often referred to as a cofounder” he is “not a member of the Founder LLC nor a Continuing Founder.” Hence, he would not be part of the cohort of seven founders who would jointly control more than 50.1% of shareholder voting power. Mann’s percentage of shares is unknown.
A spokesperson for Anthropic confirmed Monday that there have been no changes to Mann’s role, and “it’s still fair to refer to him as a cofounder.” Mann’s LinkedIn page lists him as such.
So why is Mann, who everyone agrees is a founder, seemingly shut out?
Mann, 37, who lives in San Francisco with his wife and two children, co-leads Anthropic Labs, (opens in new tab) the company’s experimental arm, alongside Mike Krieger of Instagram. Mann helped develop GPT-3 at OpenAI, left in 2021, decamping with seven others who went on to found Anthropic. He left OpenAI because “safety wasn’t the top priority there,” he said in a 2025 podcast interview. In June 2021, he wrote on the “life updates” section of his substack: “Announced our new company, Anthropic (opens in new tab).”
But despite his cofounder title, which is also displayed on his personal site and in various Anthropic materials, the company has been inconsistent in describing Mann’s role.
He’s been repeatedly cut from the company’s founding story. At a 2024 Bloomberg summit, CEO Dario Amodei stated (opens in new tab), “We have seven cofounders (opens in new tab).” That December, Anthropic published a YouTube video titled “A conversation with our cofounders,” which included seven.
In Silicon Valley, “cofounder” is much more than a vanity title.
“‘Founder’ in colloquial terms means somebody who helps get the startup going. But it is not a legal term,” said Ann Lipton (opens in new tab), a professor at University of Colorado Law School who has worked for the Securities and Exchange Commission. The IPO footnote makes clear what Mann’s continued rights are, she said.
“He’s not going to have continuing governance rights in the firm. He may continue to have economic rights, but we don’t know what they are,” she said, noting that Mann is not legally disputing this state of affairs, as that would have had to be disclosed. “It’s possible there was no disagreement; he just didn’t want to be involved with the public entity. That’s a lot of work. There are 20 zillion possible explanations that are completely benign.”
Mann is absent from Anthropic’s leadership page, which was created in August. But in 2025, the company identified him as a cofounder at its Tokyo Builder Summit (opens in new tab). Yet in a June 2026 (opens in new tab) interview, Amodei again stated that the company started with seven. All the while, Mann has continued giving interviews as a cofounder, including on “Lenny’s Podcast” in 2025, telling the host, “If we do our jobs, we will have safe aligned superintelligence.”
Mann did not return a request for comment.
Anthropic would have known the contents of its IPO filing on Oct. 14 yet was still publicly calling Mann a cofounder in the Singapore press release. “If they already knew that they were defining a specific group of people as founders in this document to the point where they have to disclaim that this guy is associated with it, and they were very recently still referring to him as a cofounder publicly … [that] raises a question whether a last-minute change was made,” said Lipton.
Benjamin Mann has been an integral part of Anthropic since its founding in January 2021 and, given his role in establishing Anthropic, is often referred to as a co-founder. However, Mr. Mann is not a member of the Founder LLC nor a Continuing Founder upon the completion of this offering, and accordingly will not participate in determining how our Class F common stock is voted. Except as set forth in this paragraph, references to our “co-founders” elsewhere in this prospectus do not include Mr. Mann. — Anthropic’s S-1 filing, Footnote 13
The S-1 filing is unusual even by Silicon Valley standards. “This is just an extremely complex structure,” said Lipton, noting that it gives significant governance power to employees who don’t have many shares. The stated purpose is to make sure AI isn’t misused.
“There isn’t a lot of precedent for this.” Still, she added, “I don’t think there’s anything unusual or weird about somebody who was involved in a startup phase not wanting to take a public-facing governance role once they go public.”
The discrepancy might have been intentional. “It could very well be because they knew … that he wasn’t going to have a governance role, and they knew they were calling a particular group of people ‘founders’ for the purpose of governance, which is a little bit different than the actual people who actually started the company,” said Lipton.
“They clearly thought that there’s going to be confusion. You usually are going to be very careful in an IPO context,” she added. “I would not expect them to continue to refer to him as cofounder.”
Lipton sees the footnote as indicating that Mann “was a founder in the factual colloquial sense. But now that they have defined the term to have a legal meaning for the purpose of this document they don’t want to confuse people,” she said.
“I don’t necessarily think it means anything nefarious, but it could. I mean, he was there, and now he’s not. We just don’t know why.”