Corporation have the major advantage of protecting the liability for owners (i.e. shareholders), which is limited to the funds contributed. This facilitates capital formation. Corporations control over 75% of assets and sales in the United States (although they represent less than 20% of the business population).
All the major firms in the United States are corporations. Some, such as AT&T, have millions of owners, i.e. shareholders, directly, or indirectly through pension and retirement plans. Such firms have easier access to new funds from investors than small and not so well-known firms do.