I'm pretty sure most of their flagship bi-annual IP are actually made in collaboration with their studios working together. Either way, they own all of the studios that work on their games, and I think most if not all of them even have the Ubisoft name. It seems like they run their studios a lot more like say Nintendo EPD is run, rather than say Retro or Monolith to Nintendo, only with entire studios instead of teams within a larger studio.
Also they own the studios so they're really a developer and publisher. But if you took the OP to only mean single studio developers, or developers who can't self-publish, I understand.
There is a main studio for every IP, regardless of whether another main or satellite studio helps. We don't go around calling The Order a Santa Monica game even though they helped on it. We don't call Bloodborne a Studio Japan game even though they helped on it.
Ubisoft functions as a publishing unit, providing funds to their respective development teams, who are the actual developers. Ubisoft Montreal is not Ubi Paris, who are not Ubi Toronto, who are not Ubi Singapore, outside of sharing the same parent company.
But yeah, I read it as the individual teams. If that is not the case then yeah I get the overall company angle too.