The sole proprietorship is the simplest business form under which one can operate a business without any company registration. It is an unregistered business entity which is owned and managed by one person. The sole proprietorship is a popular business form due to its simplicity, ease of setup, and nominal cost. It simply refers to a person who owns the business and is personally responsible for its debts / losses. A sole proprietorship can operate under the name of its owner or it can do business under a fictitious name. The fictitious name is simply a trade name.