52. The Committee expects that the external auditor of a bank has specialised knowledge and competence in auditing banks. The external auditor will require specialised knowledge and experience in accounting for the ECL estimate, but may also need to use other experts. The identification of the need for auditor's experts requires auditor judgment. Auditor's experts have expertise outside accounting and audit [ISA 620, Using the Work of an Auditor's Expert, paragraph 6 (a) "An individual or organization possessing expertise in a field other than accounting or auditing, whose work in that field is used by the external auditor to assist the external auditor in obtaining sufficient appropriate audit evidence. An auditor's expert may be either an auditor's internal expert (who is a partner or staff, including temporary staff, of the external auditor's firm or a network firm), or an auditor's external expert".]. An auditor's expert can be an external expert or from the audit firm. In this supplemental note, the term "auditor's experts" is used consistently with the definition in relevant internationally accepted auditing standards [ISA 620, Using the Work of an Auditor's Expert. Auditing standards differentiate between an auditor's expert (ISA 620) and an individual or organisation with expertise in a specialised area of accounting or auditing (ISA 220, paragraph 14). It is not always clear whether a matter falls outside of the accounting or auditing fields, in particular with more recent standards. In these circumstances it is a matter of the external auditor's professional judgment whether an individual is an auditor's expert (ISA 620, paragraph A2).].