All of them are when they become national security concerns. The executive branch could write the OpenAI board a letter directing them on what to do if it were a national security need. This has been done many times before, though usually limited to the defense industry in wartime, but as Snowden has showed it has been done in tech as well.
Except that is literally not true and the Government loses in court to private citizens and corporations all the time because surprise: people in America have rights and that extends to their businesses.
In wartime, pandemics, and in matters of national security, the government's power is at its apex, but pretty much all of that has to withstand legal challenge. Even National Security Letters have their limits: they're an information gathering tool, the US Government can't use them to restructure a company and the structure of a company is not a factor in its ability to comply with the demands of an NSL.
The PATRIOT act extended the wartime powers act to apply in peacetime, and there are other more obscure authorizations that could be used. I used to work in the defense industry. It was absolutely common knowledge that the government could step in to nationalize control (though not the profits of) private industry when required. This has been done in particular when there are rare resources needed for supersonic then stealth technology during the Cold War, and uranium in the 40’s and 50’s.
