Security

A security is a fungible, negotiable interest on behalf of financial value. Securities are generally categorized into debt and equity securities. The company or other individual issuing the security is called the issuer.
Securities may be represented by a certificate or, more characteristically, by an electronic book entry interest. Certificates may be bearer, meaning they entitle the holder to rights under the security merely by holding the security, or registered, meaning they give the right the holder to rights only if he or she appears on a security register maintained by the issuer or an intermediary. They include shares of corporate stock or mutual funds, bonds issued by corporations or governmental agencies, stock options or other options, limited partnership units, and a variety of other formal investment instruments that are negotiable and fungible.