A document indicating ownership in a corporation is often referred to as common stock. It identifies an equity position in a business. The document or certificate is commonly referred to as a security and provides certain rights to the holder (owner). These rights include voting and residual value upon liquidation of the company.
Initial Public Offering
When a corporation desires to go public it seeks approval from the Securities and Exchange Commission. Once approved, a prospectus is presented for the public to review and a date is set to sell the initial batch of shares. This is commonly called an IPO.