Don't they? In the UK at least they need to be disclosed to Companies House and that data is public.

Sure enough - but that is for the UK subsidiary, which is just going to follow the US companies directions. They wouldn't be independent.

[https://find-and-update.company-information.service.gov.uk/c...]

Interestingly, they're overdue on their bill with Companies House it looks like. Oops.

Lots of entities in Delaware named Twitter Inc. (3) plus what might be a holding company or two. Hard to tell without more digging.

[https://icis.corp.delaware.gov/eCorp/EntitySearch/NameSearch...]

I was just saying more generally, I don't know if the US has similar rules. Also I think the legal entity has changed to X Corp now.

This is common in the US too, usually they need to file with their state. Going private will often remove the need to file publicly with the SEC though (though even then, that depends on things like how many shareholders there are, not the trading status as such).