A subsidiary, subsidiary company, or daughter company, is a company that is owned or controlled by another company. The subsidiary can be a company, corporation, or limited liability company. In some cases it is a government or state-owned enterprise. The controlling entity is called its parent company, parent, or holding company. In the United States railroad industry, an operating subsidiary is a company that is a subsidiary but operates with its own identity, locomotives and rolling stock. In contrast, a non-operating subsidiary would exist on paper only (i.e., stocks, bonds, articles of incorporation) and would use the identity and rolling stock of the parent company. Subsidiaries are a common feature of business life, and all multinational corporations organize their operations in this way. Examples include holding companies such as Berkshire Hathaway, Time Warner, or Citigroup; as well as more focused companies such as IBM or Xerox. These, and others, organize their businesses into national and functional subsidiaries, often with multiple levels of subsidiaries.