Company nationality is a somewhat diffuse concept. IKEA, Chrysler, Fiat and Citroen have holding companies in the Netherlands. Should they be considered Dutch companies? Share owners (also of American listed and incorporated companies) are from all over the world.
It depends, right? In case of Booking, aren’t other subsidiaries also selling airline tickets? It would be reasonable for all those sites to have a common platform for data and that means the holding company is the right target to sue.