They mention Hiive specifically.

> We are aware of individuals or investment firms offering access to Anthropic financing rounds, or offering to purchase your Anthropic shares in violation of our transfer restrictions. To be clear, the following firms are not authorized to buy or sell Anthropic shares:

Open Door Partners

Unicorns Exchange

Pachamama

Lionheart Ventures

Hiive (new offerings)

Forge (new offerings)

Sydecar

Upmarket