Anthropic halves unauthorised platform list after pushback

Anthropic halved its list of unauthorised secondary-market trading platforms on Friday, cutting the named venues from eight to four after the original warning triggered panic among investors and drew a sharp response from Hiive chief executive Sim Desai.

The revised list, posted on Anthropic’s Claude Help Center, names four platforms investors should avoid: Open Door Partners, Unicorns Exchange, Pachamama, and Upmarket. The earlier notice had included Hiive — one of the largest secondary venues — and Desai said nobody at Anthropic had contacted his company before publication.

Had Anthropic approached us before their aggressive new stance and corresponding public statements (they did not), we would have gladly worked with them to deliver a unified message to the market.

— Sim Desai, CEO of Hiive

The dispute flared just days after Anthropic closed a US$65 billion funding round that valued the company at US$96.5 billion (about $150 billion), Bloomberg reported. That figure puts Anthropic second only to OpenAI among privately held AI firms and has turned its shares into some of the most actively traded on secondary markets — the venues where accredited investors and institutions buy and sell stakes in companies that have yet to list. When your valuation sits at $96.5 billion, who handles trades in your stock stops being a detail.

Anthropic described the original list as a safeguard for shareholders: unauthorised platforms could expose sellers to fraud, contractual breaches, or trigger the company’s right of first refusal. That didn’t stop the breadth of the list from drawing immediate fire. Eight platforms, ranging from obscure operators to well-known names like Hiive, were lumped together without distinction. One phone call ahead of the notice, Desai told Bloomberg, could have produced a statement the market was able to rely on.

Why Hiive and three others were removed the second time around is something Anthropic’s support page does not address. The four that stay — Open Door Partners, Unicorns Exchange, Pachamama, and Upmarket — are smaller and less prominent than Hiive, which has grown into a dominant secondary-market operator. An Anthropic spokesperson would not comment beyond the updated page.

For Australian AI founders and investors, the episode doubles as a live case study in how companies sitting atop the valuation curve handle the secondary market forming around their equity. Several AI startups in Sydney and Melbourne have started fielding inquiries from secondary platforms as their own valuations rise.

Naming platforms publicly comes with risk.

SecondaryLink, a specialist publication covering the private-share trading market, said in its weekly roundup that Anthropic’s reversal “highlights the growing tension between issuer control and investor liquidity in the late-stage AI market.” AI companies are staying private longer and at higher valuations. Secondary trading will keep pushing against whatever policy any single company sets — that tension does not resolve with one narrowed list.

The company has given no sign that its broader stance on unauthorised secondary sales is softening. The updated page continues to warn that sellers who trade on an unauthorised venue could see the company void the transaction or pursue legal remedies. Markets absorbed the narrower list without incident. No further response came from the platforms that were removed, or from the investors who trade through them.