A division of a business, sometimes called a business sector or business unit (segment), is one of the parts into which a business, organization or company is divided. The divisions are distinct parts of that business. If these divisions are all part of the same company, then that company is legally responsible for all of the obligations and debts of the divisions. However, in a large organization, various parts of the business may be run by different subsidiaries, and a business division may include one or many subsidiaries. Each subsidiary is a separate legal entity owned by the primary business or by another subsidiary in the hierarchy. Often a division operates under a separate name and is the equivalent of a corporation or limited liability company obtaining a fictitious name or "doing business as" certificate and operating a business under that fictitious name. Companies often set up business units to operate in divisions prior to the legal formation of subsidiaries.