Anthropic share mania is getting weird enough that the company says some deals are void

Investors are getting so desperate for Anthropic exposure that some are offering partnership stakes, wire-ready cash, proof-of-funds screenshots, and even a house just to get into the cap table. That would already be strange. What makes it more revealing is that Anthropic says many unapproved stock transfers are void, which means part of this scramble may be chasing access the company refuses to recognize.

The frenzy also says something more important than "hot startup gets absurd bids." According to Business Insider, Jesse Leimgruber, founder of software startup Neo, said a well-known growth fund offered a $1.05 trillion valuation for his Anthropic shares after he hinted online that he might sell. That is far above Anthropic's own last official mark of $380 billion, set in February when the company announced a $30 billion Series G round.

The mechanics of the scramble are the story. Business Insider reported that Leimgruber received hundreds of inbound offers, including investors promising to wire millions within 48 hours, others sending unsolicited bank screenshots, and one large venture firm offering to make him a general partner in exchange for shares. In a separate report, Business Insider wrote that banker Storm Duncan offered his $4.8 million Marin County estate for Anthropic stock.

That behavior makes more sense once you look at the supply side. Glen Anderson, chief executive of private-securities merchant bank Rainmaker Securities, told Business Insider that "the problem is there are no sellers." Bradley Horowitz, a general partner at Wisdom Ventures and an early Anthropic investor, told the outlet his firm gets daily offers "from the ridiculous to the sublime" for its stake. In thin private markets, a shortage like that can turn every available share into a status object.

Anthropic itself is warning that some of the market's favorite workarounds do not count. In a February support notice, Anthropic said that any sale or transfer of its stock not approved by the board "is void and will not be recognized" on the company's books. The company also said it does not permit special purpose vehicles, or SPVs, to acquire its stock, meaning pooled investment structures that buyers often use to get exposure to hard-to-access private companies may be invalid here.

That turns the secondary-market frenzy into a more useful signal than the headline valuation alone. Buyers are not just bidding Anthropic higher. They are trying to engineer around scarcity, and the company is saying some of those engineering tricks fail at the legal layer. That matters because Anthropic is no longer being priced only as another frontier-model lab. It is being priced as one of the few ways private investors can buy into the part of the AI market that still looks supply-constrained and revenue-hot.

Anthropic has fed that demand with unusually aggressive growth claims. In February, the company said it had raised $30 billion at a $380 billion post-money valuation, with run-rate revenue of $14 billion and more than $2.5 billion of run-rate revenue from Claude Code, its software-coding product. By late April, Business Insider reported that Anthropic's valuation on Forge Global was hovering around $1 trillion, citing Forge chief executive Kelly Rodriques.

That does not mean Anthropic is worth $1 trillion in the clean, public-market sense. Secondary indications can get weird when almost nobody wants to sell and everybody wants the same story. The vivid anecdotes here also come through a small group of participants and a single reporting outlet. Leimgruber's own evidence for the $1.05 trillion approach, for example, is an X post saying he had just received the offer from a well-known growth fund.

Still, the pressure is real. Earlier this month, Business Insider reported that Anthropic had fielded venture offers valuing it as high as $800 billion. Duncan, the banker offering his house, told Business Insider that Claude Code would probably triple his firm's throughput while cutting costs by 50 percent. That may be one buyer's pitch, but it helps explain why investors are acting less like patient shareholders and more like people trying to secure allocation into a scarce utility.

What to watch next is whether this remains a sideshow of absurd bids or starts changing real company behavior. If Anthropic keeps compounding Claude-driven demand while insisting that many unofficial share transfers are void, the gap between official price discovery and gray-market appetite will keep widening. Private-market plumbing looks orderly until a frontier AI company becomes too desirable to trade normally.