3. This supplemental note elaborates on the 2014 guidance. While that guidance remains relevant, the changes brought about by ECL frameworks mean that further guidance is required. This note includes expectations for the audit of a bank's financial statements specifically related to the audit of ECL estimates so that the audit committee understands the Committee's expectations and can discharge its responsibilities for the effectiveness of the external audit. A bank's audit committee has a key role in fostering a high-quality bank audit through the effective exercise of its responsibilities with respect to the external auditor and the financial statement audit [Basel Committee on Banking Supervision, External audits of banks, March 2014, paragraph 13.]. Supervisors can assist by setting expectations.