Anthropic and OpenAI have updated their stock transfer policies, declaring that any shares purchased through unauthorized channels are void and confer no shareholder rights or economic value, regardless of platform or method. Both companies specifically targeted direct sales, SPVs (special purpose vehicles), tokenized interests, and forward contracts as invalid without written board approval. Anthropic published a blocklist of firms and platforms—including major regulated secondary marketplaces like Forge Global and Hiive—whose transactions will not be recognized. If an initial transfer lacked approval, every subsequent transaction in the chain is also void. The new policies affect regulated and unregulated entities alike, as demonstrated by sharp drops in token prices for Anthropic and OpenAI shares on PreStocks after the announcements. Legitimate, company-authorized secondary stock sales remain allowed, as with OpenAI’s 2025 board-approved tender offer. However, the companies are warning buyers that it is not the regulation of a platform that determines validity but whether explicit company consent was given. Soaring valuations and investor demand have driven attempts to bypass restrictions, but both firms are now firmly enforcing direct control over every stock transfer.