Sole Proprietorship - A sole proprietorship, also known as a trader firm or proprietorship, is a business firm that is owned and run by one individual. A sole proprietor may use a trade name or business name other than his or her name. Registration not required - In summary, biggest advantage is quick formation and low compliances. However, the biggest disadvantage is unlimited liability.
Partnership - liability is joint and unlimited. Registration not compulsory.
Active partners take part in day-to-day operations of the business, in addition to investing in it. Active partners are entitled to a share of the enterprise's profits.
Sleeping partners invest in the business and are entitled to a share of its profits, but do not participate in day-to-day operations.
Public Sector Undertaking (PSU) - Alternatively known as Public Sector Enterprise (PSE). It may be public limited company listed on stock exchanges with major ownership by a state government or a central government of India or it may be unlisted entity with major ownership by a state government or a central government of India. Some of these entities are formed as business entities through special legislation, where these entities are governed by the statutes of these legislation and may or may not be governed by company laws like a typical business entity.
One-person company - It is a type of private company which can have only one director and member.
Unlimited Company - A company, similar to its limited company (Ltd, or Pvt Ltd) counterpart, but where the liability of the members or shareholders is not limited.
Incorporation Company - Incorporation is the formation of a new corporation. The corporation may be a business, a non-profit organization, sports club, or a government of a new city or town.