Anthropic and OpenAI updated their stock transfer policies on Tuesday, declaring any sale or transfer of stock without board approval as 'void,' not voidable. The buyer would not be recognized as a shareholder and would have no economic rights. Both companies named unauthorized channels including direct sales, SPVs, tokenized interests, and forward contracts. Anthropic published a blocklist of platforms including Forge Global, Hiive, and several others. This crackdown targets secondary market activities that bypass company approval, such as layered SPVs and tokenized wrappers. The move immediately affected tokenized shares: Anthropic token on PreStocks dropped from $1400 to $900, and OpenAI's equivalent crashed similarly. However, authorized tender offers, like OpenAI's $6.6 billion employee cash-out in October 2025, remain legitimate. Robinhood's $75 million OpenAI stock purchase through a regulated fund faces uncertainty, as OpenAI's written consent has not been confirmed. The companies aim to enforce approval for all transfers, impacting even regulated platforms like Forge Global.

Key facts

• Anthropic and OpenAI declare unauthorized stock transfers void, with no shareholder rights.
• Blocklist includes Forge Global, Hiive, and other secondary market platforms.
• Tokenized shares on PreStocks crashed after the announcement.
• Authorized tender offers like OpenAI's $6.6B employee sale remain valid.
• Robinhood's $75M OpenAI purchase faces uncertainty without written approval.