Interested parties (also called stakeholders in ISO terminology) are all persons, groups, or organizations that place requirements on your ISMS or are affected by its outcomes. Typical examples include customers, regulatory authorities, business partners, employees, and shareholders. ISO 27001 clause 4.2 requires you to identify these parties and determine their relevant requirements. The results feed into the scope definition and risk analysis. Review the list regularly, as new business relationships or regulatory changes may introduce additional interested parties.