A sole proprietorship, also known as a sole tradership, individual entrepreneurship or proprietorship is a type of enterprise owned and run by one person and in which there is no legal distinction between the owner and the business entity. A sole trader does not necessarily work "alone"—it is possible for the sole trader to employ other people.

A sole proprietor may use a trade name or business name. They may have to legally trademark their business name if it differs from their own legal name, the process varying depending upon country of residence

Registration of a business name for a sole proprietor is generally uncomplicated unless it involves the selection of a name that is fictitious, or “assumed”. The business owner is required to register with the appropriate local authorities, who will determine that the name submitted is not duplicated by another business entity. Furthermore, the business owner must complete a form submitted to the governing authority to acquire title as a “DBA” or "doing business as”.

This is transposed by the unlimited liability attached to a sole proprietary business. The owner carries the financial responsibility for all debts and/or losses suffered by the business, to the extent of using personal or other assets to discharge any outstanding liabilities.