Anthropic and OpenAI Warn Buyers: Unauthorized AI Startup Shares May Be Worthless

In brief

• Both Anthropic and OpenAI have declared any stock transfer without board approval void.
• Anthropic published a blocklist of unauthorized platforms, including Forge Global and Hiive—two of the largest regulated private-share marketplaces.
• The $6.6 billion OpenAI employee cash-out was a…