Anthropic Sends Jolt Through Market for Buying Shares in Hot Pre-IPO Startups

In the moments after Anthropic expanded a ban on popular ways to buy its shares, investor chatrooms around the world lit up.

“Are we screwed?” one person wrote in a WhatsApp chat for family offices with several hundred members. Similar questions reverberated more publicly across X, Reddit and Chinese-language social media, as investors worried whether their shares in the artificial intelligence developer — one of the most coveted private companies — had suddenly become worthless.

Days later, there is little clarity. Anthropic PBC issued a stern warning on its website last week about unauthorized sales, taking the unusual step of naming eight firms whose offerings would be considered void. It also expressly prohibited investors from buying shares through special purpose vehicles, a common tool to raise financing.

Both Anthropic and rival OpenAI have long warned against unauthorized transactions — fine print overlooked by eager buyers until last week when the Claude maker removed any ambiguity. Publicly traded funds touting exposure have plunged on the back of the update and private brokers are reeling.

Sim Desai, founder of Hiive, one of the secondary trading platforms called out by Anthropic, said his company only facilitated deals that had Anthropic’s approval. Sohail Prasad, whose closed-end fund has lost about 25% of its share value in the intervening days, was adamant on X that his fund’s Anthropic holdings were valid.

“Anthropic threw a bomb into the market,” said Idan Miller, who runs Unicorns Exchange, another platform named by Anthropic. “We were unfortunately involved in a really bad and unjust way.”

Representatives for Anthropic declined to comment. A representative for OpenAI said the company had taken action against unauthorized platforms offering its shares.

Over the last two years, a niche private market sector has ballooned into a multibillion-dollar investing spree for stakes in Anthropic, OpenAI and SpaceX ahead of their blockbuster expected public listings. These firms, at the forefront of the tech boom, have created tremendous paper gains for large venture firms and institutional funds. Some insiders have sought to monetize their exposure as family offices, retail investors and wealthy individuals are clamoring to get in, any way they can, feeding a booming shadow stock market.

Anthropic is in discussions for additional funding at a valuation north of $900 billion, Bloomberg News reported, and secondary traders have marketed shares at even higher prices.

The crackdown "marks the beginning of a reckoning over our modern private markets," wrote Anat Alon-Beck, a law professor who specializes in corporate governance at pre-IPO companies at Case Western Reserve University. “It raises questions like, who actually owns what? Who bears the risk when shadow ownership structures collapse? Should trillion-dollar private companies continue to operate outside the disclosure framework that governs other big companies?"