Anthropic Says Unauthorized Share Trades Are Void, Roiling AI’s Shadow Market

Anthropic has declared invalid any purchases of its private shares made without approval from its board, fueling turmoil in the market for pre-IPO AI stocks. The move has also raised the prospect of a wave of lawsuits as valuations of artificial intelligence companies soar.

Bloomberg reported on May 18 that Anthropic recently posted a notice on its website naming eight special purpose vehicles, or SPVs, including Forge Global, OpenDoor Partners and Unicorn Exchange, and said share transactions conducted through them are invalid.

"Any sale or purchase of Anthropic stock or rights to Anthropic stock without board approval is void," the company said. Such transactions are potentially fraudulent and will not be reflected in the company’s books and records, it added.

The notice sent the market into immediate confusion. As AI company valuations have surged, a growing number of retail investors have sought to buy private shares before an initial public offering.

Bloomberg reported that one investor wrote in a WhatsApp group chat, "Are we all screwed?" Similar concerns spread on Reddit, X and Chinese-language social media.

Forge, one of the platforms cited by Anthropic, is a widely used trading venue that Charles Schwab acquired for $660 million in November 2025. Anthropic has recently been discussing a fundraising plan with venture capital firms at a $900 billion valuation. In those secondary markets, however, its private shares were reported to have traded at valuations of about $1.6 trillion.

Bloomberg said the shadow stock market grew rapidly as family offices, wealthy investors and retail buyers scrambled for access to AI investments. They are now questioning whether their Anthropic shares may have suddenly become worthless.

Legal experts say Anthropic’s declaration could set off courtroom battles among private-share investors. Investors paid for stakes they believed would give them ownership, but there is a rising chance those claims will not be recognized. Anthropic also said third parties claiming to sell Anthropic stock to the public were likely offering investments with little or no value. Shares of closed-end funds that had disclosed investments in Anthropic fell as much as 30% after the notice.

Anat Alon-Beck, a professor at Case Western Reserve University, said the episode signals a reckoning for modern private markets. It raises fundamental questions about actual ownership and legal liability.

Park Han-shin, Korea Economic Daily reporter phs@hankyung.com