Say ABC Corp. sells common shares to the general public on the market in order to generate capital to finance its business operations. This means ABC Corp. is an issuer, and it's therefore required to file with regulators, such as the Securities and Exchange Commission, disclosing relevant financial information about the company. ABC must also meet any legal obligations or regulations in the jurisdiction where it issued the security.
Writers of options are occasionally referred to as issuers of options because they also sell securities on a market.
Investment dictionary. Academic. 2012.