The maker of Claude says buyers should assume its private share offerings are invalid. The shadow market kept climbing anyway, briefly outpacing OpenAI.
Anthropic does not want outside investors buying its shares. The AI company behind Claude has said so explicitly, on its support site, to TechCrunch, and to Decrypt: any special purpose vehicle (a pass-through pool that lets many investors club together to buy a single block of shares), secondary platform, or on-chain token offering Anthropic stock should be "assumed invalid."
The implied valuation of Anthropic on private and on-chain pre-IPO venues has climbed to roughly $1.2 trillion, up about 20 percent in the past week and roughly 900 percent since October 2025 (crypto.news, cryptonews.net). That mark, briefly, exceeded OpenAI's implied pre-IPO price on the same on-chain index, a first. Most private holders are refusing to sell at those levels. At least one broker told Business Insider demand is so far ahead of supply that they could be on a beach if they could satisfy every name on the waitlist.
The mechanism behind the numbers starts with a constraint. Anthropic is not a public company, so the only path to its shares for outside investors is the secondary market: buying stakes held by employees and early backers. Demand on that market is outpacing supply. Three unofficial venues have emerged to channel it. On-chain aggregators such as Moonberg run pre-IPO instruments backed 1:1 by underlying shares, the layer that briefly put Anthropic ahead of OpenAI on the implied-valuation index. Conventional secondary desks, including Forge Global, match individual buyers to private sellers. And dealers have built SPVs on top to bundle small checks into single blocks.
The SPV version, the one Business Insider flagged in February, works like this. A promoter assembles a fund, raises outside money, and uses it to buy a stake from an early Anthropic employee. The investor pool is charged roughly 10 percent upfront in management fees plus 10 percent of any future profits. The investors at the top of the stack do not receive direct Anthropic shares. They receive a claim on another investor's shares, typically several layers below. The result bundles many small checks into a single sale, but it also pulls the buyer several legal steps away from the company's actual cap table.
That distance is what Anthropic objects to. The company's stated policy is that any transfer of its shares into an SPV is "void" under its transfer restrictions. Forge Global's chief executive, Kelly Rodriques, has publicly described the multilayer SPV structure as a "nightmare" for the buyers at the bottom of the stack, the ones holding claims rather than shares. Anthropic and OpenAI have jointly warned investors that unauthorized AI stock offerings can be worthless.
The Business Insider feature documents offer letters that pair Anthropic shares with houses, art, and cash, including one Brooklyn property attached to a bid of roughly $5.99 million. The Kobeissi Letter's on-chain tracker has put the Anthropic pre-IPO mark near $1.2 trillion since late June, and the chart he circulated in July showed valuation running about ten-fold higher than where it sat last autumn. Those prices come from low-liquidity venues. They are signal, not audited financial data, and they can diverge sharply from whatever an actual IPO eventually clears at.
The competitive backdrop sharpens the paradox. OpenAI, the lab whose ChatGPT arguably defined the consumer AI moment, is reportedly regaining momentum ahead of its most advanced model rollout. For now the shadow market is paying Anthropic for the privilege of holding a claim Anthropic says does not exist. The company has not announced an IPO timeline, and the gap between its stated policy and the live secondary price is widening.