 It is a dual-listed company, registered in both the United States and the United Kingdom, with the former P&O Princess Cruises being relisted as Carnival plc, more commonly known as Carnival UK, which holds executive control over Cunard Line and P&O Cruises.As an American-based company, executive control of Princess Cruises was transferred to Carnival's American operations, with the formation of the Holland America Group umbrella, which comprises Princess, Holland America Line, Seabourn Cruise Line, and P&O Cruises Australia.In May 2005, Princess reacquired "Sea Princess" from P&O, which it had transferred over just two years prior.