Yes Rosie and Peter are correct. White Star Line was a British company owned outright by the Ismay family until negotiations were undertaken to join the conglomerate, International Mercantile Maritime Co. run by JP Morgan an American (who was prevented by an agreement with the British government and subsequent law from owning White Star Line directly, so chose to do so through IMM the holding company).
IMM and it's constituent shipping lines were not profitable, in part because JP Morgan overestimated each shipping lines's worth and paid too much per share. IMM itself went bankrupt three years after the sinking of the Titanic although the company managed to forge on after restructuring. After the US government finally agreed to offer subsidies to US owned, built and flagged vessels IMM was forced to sell off its foreign flagged holdings. White Star Line was sold to the Royal Mail Steam Packet Company in 1927 for less than had been paid for it 25 years earlier. RMSPC itself went bankrupt five years later and was restructured as the Royal Mail Lines Ltd. In 1934 the British government, in return for a subsidy, required Cunard and White Star to merge their operations on the North Atlantic. IMM now as a wholly American company with US flagged vessels on its register later evolved into the United States Lines.
There are some similarities today with the airline alliances, but a closer correlation would be with Rupert Murdoch, an Australian, who until the recent demerger of News Corp, an Australian/American holding company, owned various newspaper titles such as The Times (of London) plus the Fox Network. Does this make The Times an Australian paper or Fox News Australian? NO