Final answer:
A single-person firm with unlimited liability is known as a sole proprietorship, distinct from corporations, partnerships, limited partnerships, and LLCs, where the liabilities can vary and the business may be a separate legal entity.
Step-by-step explanation:
A firm owned by a single person who has unlimited liability for the firm's debt is called a sole proprietorship. In a sole proprietorship, the business is not a separate legal entity from the owner. The owner is responsible for all debts and liabilities, as well as entitled to all profits. This is in contrast to a corporation, where the business is a separate legal entity, and shareholders have limited liability for the company's debts. Similarly, a partnership involves a group of individuals running a business together, while in a limited partnership and a limited liability company (LLC), there are provisions to protect certain owners' personal assets from the firm's debts.
Private companies can take several forms, from small, owner-managed businesses to large corporations without publicly issued stock. Examples of large private corporations include farm products dealer Cargill, the Mars candy company, and the Bechtel engineering and construction firm.