This letter provides GAO’s comments on the American Institute of Certified Public Accountants (AICPA) Auditing Standards Board’s (ASB) Proposed Statement on Standards for Attestation Engagements: Common Concepts, Examination Engagements, Review Engagements, and Engagements to Report on Sustainability Information and Proposed Statement on Standards for Attestation Engagements: Amendments to SSAE Nos. 18-19 and 21 to Reflect Proposed SSAE Common Concepts, Examination Engagements, Review Engagements, and Engagements to Report on Sustainability Information. GAO promulgates generally accepted government auditing standards, which provide professional standards for auditors of government entities in the United States.