Frontier AI Companies are companies or orgs that are pushing the limits of AI capabilties. The terms "frontier lab" or "AI lab" are also sometimes used. A lot of discussion on LessWrong has to do with "what should AI companies do", "what would be good if they did differently", or how people outside the labs should relate to them.
The "Frontier AI Companies" tag is for posts that are somehow asking or answering questions related to this topic.