A company limited by guarantee. Commonly used where companies are formed for non-commercial purposes, such as clubs or charities. The members guarantee the payment of certain (usually nominal) amounts if the company goes into insolvent liquidation, but otherwise they have no economic rights in relation to the company .
a company limited by guarantee with a share capital. A hybrid entity, usually used where the company is formed for non-commercial purposes, but the activities of the company are partly funded by investors who expect a return.
a company limited by shares. The most common form of company used for business ventures.
an unlimited liability company. A company where the liability of members for the debts of the company are unlimited. Today these are only seen in rare and unusual circumstances.
There are, however, many specific categories of corporations and other business organizations which may be formed in various countries and jurisdictions throughout the world.