Carnival headquarters is in Miami. Holland America (owned by Carnival) is headquartered in Seattle.
All other claims are a facade, a fiction created to make FoC shipping a cash cow for well connected American investors.
The industry is a filthy sham and given the history of some of its major players, will find a way to dip into the $500 billion trough of cash. With scumbags like “I’ll be the oversight” Trump holding the purse strings it is inevitable that wholesale corruption will follow.